You are at the A. Ol'khovatov www-page: http://olkhov.narod.ru/news1999.htm

Here you can read news on the 1908 Tunguska event's research, and on other related topics

The last update: June 30, 2018.

1. February 17, 1999. Recently I have ended a research of a cloudiness level in association with Tunguska. The reason is that a few years ago several articles appearred in scientific journals that often about a day and less before earthquakes a cloudness level sharply decreases above tectonic faults in the area of a future epicenter. So I found data of 9 meteorological stations situated no far than 1000 km from the Tunguska epicenter (the closest is 500 km away). I have averaged the data between the stations for better statistics. And indeed, the averaged daily cloudness level shows extremely deep drop on June 29, 1908!

2. February 17, 1999. And one more meteorological peculiarity of the Tunguska. It is thought by seismologists that atmospheric pressure variations can trigger earthquakes. So I used the data of 9 meteorological stations situated no far than 1000 km from the Tunguska epicenter (the closest is 500 km away). I have averaged the data between the stations for better statistics. And indeed, the time of the Tunguska was right at the time of a maximum of atmospheric pressure strong upsurge. In the best way it is seen from the data of the Irkutsk station, which had a sampling rate every 3 hours. And the maximum of the air-pressure upsurge was between 6 and 9 a.m. local time (UT + 6h.57min.), while the Tunguska explosion was a little bit later 7 a.m.!

3. February 17, 1999. The above-mentioned results have allowed to explain the geographical peculiarities of the "night sky" anomalies of late June - early July 1908. The solution is based on empirical result that noctilucent clouds used to be accompanied by atmospheric pressure upsurge. So in the Tunguska area they had to appear just in the morning and couldn't be seen anyway. But in many places to the west of the Tunguska area the upsurge took place in the evening. Also in some other places it happened in the evening of July 1. Please, pay attention, that there were several sites where it takes June 29 and even 28!
Further investigation reveals the following. Besides this upsurge, there were also two more large upsurges: 5-7 days before the Tunguska and 5-7 after the Tunguska. And indeed, there are reports of a 'night sky' anomalies at those times!
I incline to think that these upsurges are atmospheric Rossby waves generated by powerful cyclonogenesis at that time. But I am not a specialist in this field, so I hope that some specialists would be interested to investigate.

4. February 17, 1999. An interesting example on energy (sound, light) deposition above the ground in association with a weak earthquake is the events accompanied the June 4, 1998 North Carolina earthquake.

5. February 27, 1999. Summary of the 1998 Krasnoyarsk International conference was published in EOS TRANSACTIONS of Amer. Geophys. Union, v.80, N 8, p.92, Febr.23, 1999. Remarkably, that despite its authors were supporters of 'meteorite' Tunguska, they have to mention also 'terrestrial' Tunguska. It means that the opinion that Tunguska was a terrestrial origin becomes more and more popular. It is seen even from abstracts of the conference. And please, pay attention that the 'tectonic' Tunguska doesn't state that the origin of the Tunguska forest fall was seismic waves!

6. April 26, 1999. In the Institute of the Dynamics of Geospheres a seminar (workshop) was held on numerous (computerized) simulation of Tunguska. I was one of those, who criticized the existing models of the 'Tunguska meteorite explosion'. It seems that consensus was that the Tunguska problem is not resolved still.

7. May 8, 1999. In a popular newspaper MOSKOVSKII KOMSOMOLETS an interviev with me has appeared on a probably geophysical origin of the Oct.7, 1996 Lyudinovo fireball event (about 350 km to the south-west of Moscow). There was some response.

8. May 15, 1999. My article on the probably geophysical origin of the Dec.9, 1997 Greenland fireball event appeared in the issue of KOMMERSANT newspaper. My opinion on the event also can be seen at abstracts of the 6-th International Symposium on Ball Lightning.

9. May 18, 1999. An article on 'meteorite' Tunguska has been published. It is by L. Foschini in ASTRON. ASTROPHYS., v.342, L1-L4, Febr. 1999. Possibly you can read it from here (but probably password needs). I think it would be interesting to read it, especially for those who have read my 'tectonic' Tunguska article.

10. June 2, 1999. Two Russian Central TV-channels have showed a star-like "UFO" suspended above Russian city Rostov-na-Donu for a couple of nights. One comment from a scientist stated that it is probably Venus planet, but the circumstances of the event, in my opinion, make it unlikely...

11. June 13, 1999. On June 29 a seminar 'Tunguska phenomenon was a terrestrial event' is to take place in VNII 'GEOFISIKA' (All-Russian Scientific Research Institute 'GEOPHYSICS'). Now there are 8 reports to be delivered for 'terrestrial' Tunguska.

12. June 14, 1999. I begin to construct a new section called TUNGUSKA AND OTHER PICTURES. I also suppose to change GeoPops to GeoGuide at geocities.

13. June 26, 1999. I just have been told that experts of OBSCHAYA GAZETA (newspaper) have chosen the Tunguska as the most important event of 1908. So an article on Tunguska was published in the newspaper, and the article is very favorable for my idea of 'tectonic' Tunguska.

14. June 28, 1999. On June 30 it will be the 91-th anniversary of the Tunguska event. So I would like to congratulate all Tunguska researchers and those who are interested in the event.

16. July 4, 1999. Today I took part in a TV debate on Tunguska live. Besides me, V. Romeiko took part, who defended the 'comet' Tunguska. The debate lasted for 15 minutes on TV-6 channel and we even had a direct call to studio from Uzbekistan. I have been told that the tectonic Tunguska was rather high-rated in the result.

17. July 10, 1999. Prof. G. Longo, coordinator of the "Tunguska99" expedition kindly replied on my questions:
1.How did you begin to be interested in Tunguska?
In 1991, Korado Korlevic from Visnian (Horvatia) sent to us a section of a tree that survived the Tunguska explosion. Prof. Galli had the idea to search in the tree resin of survived trees for microparticles that could have been trapped in the 1908 resin. We have gone in Tunguska to take the necessary wood samples.
2. Your first visit to Tunguska was in 1991?
Yes.
3. What are the main scientific purposes of the "Tunguska99"?
The fundamental tasks of the "Tunguska99" expedition are:
1. the study of Ceko lacustrine sediments,
2. topographic and photographic observations,
3. the search for new tree samples and possible cosmic body fragments, fallen before the explosion,
4. cosmic ray measurements during the flight Bologna-Tunguska-Bologna and in Tunguska.
1. Microparticles coming from the disintegration of the cosmic body could have been collected and preserved in different natural environments, as swamps, tree resin and lacustrine sediments. The particles from the swamps have been accurately studied by Russian expeditions since the sixties. The search for microparticles in tree resin (as done by the first Italian expedition organized by the University of Bologna in 1991) made it possible to surely date the particles on the basis of tree rings. The lacustrine sediments, to be studied by "Tunguska99" expedition, have probably the same advantage. The lake Ceko, 8 km away from the 1908 explosion "epicentre", about 500 m wide, and 47 m deep, has been chosen to search for sedimentary microparticles. The lake topography will be obtained by a satellite system (GPS) and a bathymetric profile net will be constructed with a digital echograph. By using a "sub bottom penetration system", a stratigraphic map of the bottom will be obtained to choose the necessary instruments and the sites where the samples will be collected. At the same time, a "side scan sonar" will take ultrasound photographs of the lake bottom. Then, an accurate inspection of the lake bottom will be carried out by a remotely controlled underwater telecamera. Undisturbed samples will be collected by using a "box corer" and a sampling will be performed by using a gravity corer. The search for microparticles in the collected core samples, the morphologic, chemical and isotopic analyses will be carried out in the Bologna and Turin laboratories.
2. An aerial photosurvey of the area will be performed in order to re-examine the aerophotographic material, obtained in 1938 under the direction of L.A. Kulik. The comparison between the 1938 pictures and the new survey should give further information on the direction of the trees felled by the explosion. Moreover, this comparison will make it possible to evaluate the changes of the environmental conditions and will provide a contribution to the research program of the "Tunguska Natural Reserve".
3. Some theories presented in 1996 at the Bologna conference on Tunguska presume that, before the explosion of the cosmic body, some macroscopic fragments fell in the south-east area with respect to the epicentre. Supposing that the cosmic body was chondritic, thus containing a high percentage of iron-nickel, the separation of fragments from ground rocks can be performed using neodymium magnets mounted on a special device together with a metal detector (Hall effect probe). This perfectly working system has been tested with good results during two expeditions in the western Egyptian desert and is available at the Physics Department of the Bologna University. Moreover, more samples of the trees surviving the explosion will be collected, in order to further the investigation carried out by the first Italian expedition.
4. The proposed expedition will also make it possible to measure cosmic rays with the high efficiency radiation detectors, already used by the Bologna group in Italy, Antarctica, Arctic, Everest valley (5000 m) and along the entire sea trip Ravenna-Antarctica-Ravenna. These detectors will be used to monitor cosmic rays, both during the flight Bologna-Tunguska-Bologna and during the two-week stay in the Tunguska Natural Reserve. The comparison between previous measurements and those in flight and on the ground will allow the study of cosmic ray variations with altitude, longitude, pressure, temperature, humidity, and solar activity.
Further information on the expedition is given at the Web site http://www-th.bo.infn.it/tunguska.
4. What are the main obstacles you meet?
Budget and Russian bureaucracy (no doubt that it is the best on the planet).
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That was Prof. G. Longo's interview with me. Despite that I am for the "tectonic Tunguska", I hope that the expedition's results will be useful. I hope to "monitor" the expedition's development and to post it at this www-site.

18. July 15, 1999. I just have been told by MOSCOWSKAYA PRAVDA correspondent Katya Golovina that about 23.30 July 14, the "Tunguska99" expedition was about to take off soon from the Chkalovskaya military airfield to Krasnoyarsk on IL-20M airplane. There was some delay due to the expedition's late arrival to Chkalovskaya and due to custom-house checking.
Futher details from another source. The departure was about 24.00. According to Russian laws the expedition left satellite telephones and radiostations. But they were replaced with other ones, supplied by GosNiias.
By the way, maybe it could be interested to somebody, that the IL-20M airplane is adapted former Russian reconnaissance airplane. The plane is to be based in the town of Ust'-Ilimsk (300 km from the Tunguska epicenter) and to make passes over the epicenter area surveying.
Some info on the expedition participants. Nataliya Kolesnikova doesn't take part in the expedition. Astronaut G. Grechko also doesn't join it.
"Fire-alert" situation was announced in Krasnoyarsk region. This summer there are 10 times more fires in taiga than last year. Simultaneously, it was announced that decline of water-level in Nizshnaya and Podkamennaya Tunguska rivers has led to rejection of supply-by-ships over the rivers since July 14. Food supply have begun by EMERCOM airplane to Tungussko-Chunskii district from Krasnoyarsk.
Large areas of taiga near Angara-river reddened. The reason is unknown, as scientists can't get to the areas due to lack of funds. Also there is a strong upsurge of pests, destroying agriculture and taiga.

19. July 16, 1999. Today the Tunguska99 expedition successfully has reached Cheko Lake. I have been told by Tanya Baskanova that the expedition's equipment took almost all free space inside Mi-26 helicopter and members of the expedition had to sit around it. Fortunately, some chairs were brought.
IL-20M airplane is in Ust'-Ilimsk airfield, commencing survey passes over the epicentral region.

20. July 22, 1999. I have been informed that a bad weather prevents the survey flights of the IL-20M airplane.
Today morning Russian TV informed about critical situation with the food supply in Evenkia (see pos.18). Money (finance) for the supply have disappeared. So the EMERCOM airplane has a little to transport. Questions of criminal investigation and possible residents evacuation are raised.

21. July 24, 1999. Katya Golovina, correspondent of MOSCOWSKAYA PRAVDA flew to Tunguska. She is to be in there on July 25.
Today my note on the Tunguska99 expedition was published by KOMMERSANT (Russian newspaper).

22. July 29, 1999. Those, who can read Russian www, can be advised to read (in Russ.) the Vasil'ev notes at http://www.irkutsk.com/tunguska. These notes give the general situation with the Tunguska research, and many facts, which were never published. The site is managed by Galina Kolobkova, who was in Tunguska research since 1959.

23. August 3, 1999. A new section of this www-site has appeared on tektites and similar anomalous rocks. Also clickings to free Mind-It service, which can inform everybody about any changes of this www-site is added to some pages (see below).

24. August 4, 1999. There was an article by V. Silyagin on Tunguska in Russian weekly NEDELYA (application to IZVESTIYA newspaper). There are general discussion of the meteorite/comet, the tectonic and the solar (i.e. that Tunguska was caused by a clot of solar plasma) interpretations.
I have been informed about an article by V. Psalomschikov in NLO (UFO in Russ.) magazine. It is about secret expedition sent by L. Beriya (head of the Stalin's secret police, who was responsible for the Soviet atomic bomb creation) to investigate the Tunguska epicenter in 1949! It is written that reconnaissance airplane twice flew over the area taking pictures, and that no strong radioactivity were discovered in the epicenter. The article refers to a story by one of Kurchatov's (scientific head of the Soviet atomic bomb project) collaborator, who took part in the expedition. There are some mistakes and contradictions in the article hinting that it can be a hoax. But if not, it would be of great importance to find the materials of the expedition.

25. August 5, 1999. I have been informed that the Tunguska99 expedition had to leave some samples (taken in the Tunguska epicenter) in the Russian custom-house. There are some attempts to take them from it.

26. August 9, 1999. I have been informed that the Tunguska99 expedition samples hardly will be transfered to Italy earlier than next week (see pos. 25).

27. August 10, 1999. Astronomer V. Romeiko and I were invited to take part in TV-discussions of Tunguska, which were broadcasted (televised) today's morning by TV ORT-channel.

28. August 13, 1999. My note "Tunguska revisited" was placed at American SCIENCE magazine www-site SCIENCENOW.

29. August 20, 1999. The above-mentioned note was published in the August 20 issue of SCIENCE magazine.

30. August 22, 1999. A new section on geophysical meteors was added to my www-site. Now it concentrates on the Dec.9, 1997 Greenland fireball event (see also entry pos.8 of May 15).

31. August 28, 1999. An article "Tayozhny desant" about the Tunguska99 expedition was published by Katya Golovina in MOSCOWSKAYA PRAVDA newspaper.

32. September 2, 1999. I have been informed that the process of transfering Tunguska samples, taken by "Tunguska99" expedition (see entry No 26), is going well. If everything is OK, then the samples could be delivered to Italy in 10-15 days.

33. September 10, 1999. Two articles by V. Bronsten on Tunguska are published in September and in the supplement 1999 issue (A137) of METEORITICS & PLANETARY SCIENCE journal. The general idea is that Tunguska couldn't be a meteorite, so it must be a comet. Those readers, who read my tectonic Tunguska article are able to evaluate the articles. The only thing which I want to note here is that the hypothetical comet must deposit the main part of its energy well above 5-7 km height, unlike assigned to Tunguska. Some other comments are made by Andrei Zlobin.

34. September 21, 1999. One more article on Tunguska is to be published in November, 1999 issue of METEORITICS & PLANETARY SCIENCE journal. And again the general idea is that Tunguska couldn't be a meteorite (this time due to "its chemical composition"), so the only way out is that it was a comet. Very interesting logic!

35. September 22, 1999. I have been informed that the Tunguska99 expedition samples are still in Russia (see pos. 26).

36. September 24, 1999. In PLANETARY AND SPACE SCIENCE, issue 6-7 (1999), p.905 I just discovered another article on "Finding of probable Tunguska Cosmic Body material" by partly the same authors as pos.34. It is again said that the discovered chemical anomalies don't agree with a meteorite. For me the most remarkable is the final phrase in its abstract: "The isotopic effects are in agreement with the increase of the Ir content observed in peat, but, at the same time, small content of Ir points to the low content of dust in the Tunguska comet that sharply differs it from Halleys comet." In other words, it means that in reality the chemical composition doesn't conform with a comet too! And I'd like to add that deiterium to hydrogen ratio in the Tunguska anomalies also sharply differs from all 3 investigated comets (see details in my tectonic Tunguska article)!

37. September 30, 1999. I have been informed that the Tunguska99 expedition samples are still in Russia (see pos. 26,35). But all permissions have been obtained, so the samples maybe will be in Italy on the next week already.

38. October 7, 1999. An article "Tunguska feuer - einsturz oder auswurf?" ("Tunguska fire - infall or ejection?") was published in the October issue of Austria-based astronomical magazine STAR OBSERVER Special 5, pp. 44-49. The author is German astrophysicist Dr. Wolfgang Kundt. The idea is that Tunguska was not a spacebody fall, but an ejection of large amount of gas from the Earth interior.

39. November 15, 1999. I was just informed that at last the Tunguska99 expedition samples were taken from a Russian custom-house to GosNIIAS (Moscow), and there is a hope for their fast transfer to Italy.

40. November 15, 1999. There is a very interesting www-site on so-called UFO crashes. Evidently at least some of them are geophysical meteors (or NNE, what you prefer) in reality. The fresh Oct.9, 1999 Brazilian event is especially interesting. I appreciate any info on these and similar events.

41. November 20, 1999. Abstracts of the seminar 'Tunguska phenomenon was a terrestrial event' (see pos.11 on June 13,1999) just were published in GEOLOGICHESKOE IZUCHENIE NEDR I VODOPOL'ZOVANIE issue, No.10 (1999).

42. November 22, 1999. I already have mentioned one interesting example of the earthquake lights phenomenon, associated with a weak earthquake (see pos.4 of Febr.17, 1999). Here is another interesting example of earthquake light in association with even the weaker Oct.25, 1998 Oklakhoma earthquake. Remarkably, that its depth was determined to be 13 km.

43. November 26, 1999. I just have been informed that the Tunguska99 expedition samples are still in Moscow, as there are still problems with the Russian custom-house to move them to Italy.

44. November 26, 1999. Some eyewitness's accounts of the Nov.16, 1999 MidWest, USA fireball(s) hint that maybe it was a geophysical meteor(s) . I have posted this info in a UFO-newsgroup, and informed several researchers, including in AEROSPACE CO. I would be glad to cooperate in the investigation, especially with a meteorologist.

45. December 1, 1999. During the last period I got several e-mails, asking me about Tunguska expedition in 1921. I can say, that the first investigator to reach the Tunguska forest-fall was Leonid Kulik in 1927. In 1921 Kulik travelled all over Russia to collect meteorites and info on them. He paid a lot of time to obtain accounts about 'Tunguska meteorite'. On those days it was often called 'Filimonovskii' one, as it was thought that it has impacted not far from a town of Kansk. Kulik discovered, that it was not true. For the next few years Kulik determined the impact place, which is well-known now.

46. December 2, 1999. Today I got the freshest few copies of my with Prof. Boris Rodionov book "Tunguska Light", which is just out of print. It is written as a dialogue between me and him. I explain why I think that Tunguska was not a meteorite, but a geophysical event. Boris Rodionov, being a nuclear physicist, tries to apply theory of Dirac magnetic monopoles to explain some anomalous properties of Tunguska.

47. December 9, 1999. I just have been informed that the Tunguska99 expedition samples were transfered to Italy.

48. December 11, 1999. Conducted analysis of the Dec.5, 1999 Alabama fireball event reveals that it could not be a meteoroid. Geophysical meteors is more reasonable explanation (see details here ).

49. December 13, 1999. My article on 'tectonic' Tunguska was placed by FutureFrame).

HAPPY NEW YEAR, CENTURY, MILLENNIUM!

50. January 1, 2000.
Preliminary analysis of the two Dec.26 fireball events in the southern USA points to their geophysical origin! For details click here).

51. January 3, 2000.
Evidently, there was a geometeor upsurge on Dec.26, as information on much more fireballs/UFOs appearred! For details click here).

52. January 3, 2000.
A bright bolide flew over California in the evening Jan. 2. There were also several reports about fireball(s?) about 6 a.m. Jan.3 seen in California.

53. January 5, 2000.
A fresh issue No.10 (1999) of "Tungusskii Vestnik KSE" ("Tunguska Herald of KSE") appeared. As usually, it consists of 2 main parts: scientific notes and tales. Here are the notes:
- Vasil'ev N.: "Memorandum (part 1)". It is a review of modern condition of Tunguska problem and outlook. Eyewitness's accounts, forest-fall and biology consequences of Tunguska are considered. In Vasil'ev's opinion, meteorite/comet interpretation has large problems in explaining Tunguska.
- Dyomin D.: "On possible interpretation of the energy-active area structure of Tunguska explosion". Results of the analysis of fallen trees directions hint that Tunguska explosion had very complicated rays-like structure of the energy deposition.
- Lyskovskii A.: "A computer program for analysis of Tunguska forest fall". Deals with about the same matter as the note above.
- Epiktetova L.: "On possible nature of the energy-active area, calculated by D. Dyomin". She tries to interpret the Tunguska explosion as a combination of several explosions of Tunguska meteorite fragments.
- Erokhin G., et al.: "Application of new Net technology to the Tunguska problem investigation". Probably better if you look yourself at their results here.

54. January 6, 2000.
Japanese TV-company TBS supposes to demonstrate in January a TV program devoted to Tunguska. The video was shot during a trip to Tunguska by TBS in mid-November. I just posted 4 pictures from the trip in Tunguska pictures.

55. January 7, 2000.
I just was briefed about a remarkable fireball(s) event in the western Australia on Jan.2, 2000. As soon as find out details, I will update.

56. January 14, 2000.
In a popular Japanese monthly magazine "The BUNGEISHUNJU" February 2000, vol.78, No.2, pp.316-332 an article by Takashi Tachibana appeared, devoted to the 1908 Tunguska event. He visited the Tunguska area with the staff member of TBS (see. pos. No.54 of Jan.6). I have obtained a photocopy of the article, but unfortunately, I failed to read even a single word! I have been informed that the Tunguska video was shown in Japan on Jan.3.

57. January 18, 2000.
A large fireball was seen in the morning of Jan.18 in the Yukon area, and Alaska, USA. It was registered by US satellite at 16:43:42 UTC. Duration of the flash was said to be 2 sec in the 1-micron band. Also it was detected by local seismic stations.

58. February 8, 2000.
German physicist Dr. Rainer Kayser has published an article on "tectonic Tunguska" in the Swiss magazine FACTS (No.5, Febr.3, 2000, p.102).

59. February 19, 2000.
A head of commission on meteorites and space dust, academician N. Vasyl'ev asked me to post his appeal to all researchers of Tunguska event over the world. He proposes to everyone interested in Tunguska to search for data on atmospheric anomalies about the Tunguska date, i.e. June 30, 1908. The data may be stored in archives, newspapers, magazines.

60. March 16, 2000.
Info appeared on a strange fire near a town of Little Rock, AR, USA, and related meteor sightings. You read about it here. A meteoroidal meteor hardly can produce a fire, moreover such large fire. Geophysical meteors could produce, but there are too little data to assign the event to geophysical meteors. For example, some details of the fire hint that it could be produced by burning magnesium/aluminium. It is used in military aircraft flares to avoid heat-seeking missiles. But also there are some hints that geophysical meteors can deposite magnesium substance. Apparently we should wait for results of the investigation.

61. April 9, 2000.
I just was informed that my and Judy Hall's article "Yukon fireball mystery endures" (on the Jan.18, 2000 Yukon/Alaska fireball) was published by the Canadian WHITEHORSE STAR newspaper. This giant meteoroidal fireball was accompanied with some remarkable phenomena which hard to explain.

62. May 25, 2000.
A few days ago the 8th meteor expedition has returned from the 1996 Kaluga fireball fall area. It was the largest expedition (up to about 130 participants!), and the fall area was searched very carefully. As I have predicted earlier, they found no trace of a "meteorite fall" this time too. Moreover, after this expedition many of its participants have to come to conclusion that it was not a meteorite!

63. June 2, 2000.
Details of a search for remnants of the Jan.18 Yukon/Alaska fireball were released.

64. June 16, 2000.
My poster report on geophysical meteors was delivered at ICOPS 2000 (27th IEEE International Conference on Plasma Science) a few days ago. (Thanks to Dr. Don Baker of Los Alamos Lab. for his interest and help!)

65. June 17, 2000.
Data posted at NUFORC point that the April 28, 2000 Washington-British Columbia fireball was non-meteoroidal. My additional short investigation favor for a geometeor.

66. June 30, 2000. Today it is the 92-th anniversary of the Tunguska event. So I would like to congratulate all Tunguska researchers and those who are interested in the event. A couple expeditions is expected this summer to visit Tunguska.
Forthcoming publications that I am aware, are 2 articles by astronomer V. Bronsten in PLANETARY AND SPACE SCIENCE, and in ASTRONONY & ASTROPHYSICS. Both considered Tunguska as a comet. Readers are aware about my (and many other researcher's) opinion on the "cometary Tunguska", so I don't comment it here.

67. July 10, 2000.
A new issue No.11 (2000) of "Tungusskii Vestnik KSE" ("Tunguska Herald of KSE") appeared (about a previous issue see pos.53). This issue is marked as publication of the Tomsk State University. As usually, it consists of 2 main parts: scientific notes and tales. Here are the notes:
- Vasil'ev N.: "Memorandum (part 2)". It is a review of modern condition of Tunguska problem and outlook. Search for the "Tunguska meteorite substance" is reviewed. In Vasil'ev's opinion, there is no proofs of the Tunguska spacebody substance discovery.
- Sal'nikova G.: "On search for substance in the area of the Tunguska catastrophe associated with thermal effects of the explosion". Discussion of some methodological problems. Also on tektite-like substance discovered in the epicentral area.
- Doroshin I.: "On search of Tunguska meteorite substance in peat". Discussion of some methodological problems.
- Doroshin I. et al.: "On a trace of the Tunguska meteorite substance fall-out". Additional investigation reveals no traces of the Tunguska comet fall-out declared by Florenskii K. in early 1960s.
- Kolesnikov E. et al.: "Traces of cometary substance in peat from the place of the Tunguska spacebody explosion". Almost the same info as discussed in pos.36.
- Alekseev V. et al.: "Optical properties of carbon nano-particles. Tree burns in the area of the Tunguska catastrophe". Investigation of thin carbon films luminiscence points that Tunguska trees were burnt by impulse (of light or plasma).
- Zhuravlyov V.: "Bolid as a reactor of ideas". Discussion (criticism of scientific aspect, in general) of the Anfinogenov J., and Budaeva L. book "Tunguska sketches" (1998).
- Anfinogenov J. et al.: "An expedition into the area of the Teleutskoe Lake meteorite shower fall". Preliminary report on succesful search for fragments of the moderate meteoroid, which fragments fell in Altai in 1904.
- Anfinogenov J. et al.: "The Jone's rock is an exploding rock". The Jone's rock investigation reveals its strong interior stress.
- Anfinogenov J. et al.: "Dating peat levels during search for the Tunguska meteorite substance". Correct dating of peat samples is a problem.
Please, pay attention that some of these items already were discussed in abstracts of the 1998 Tunguska conference.

68. July 13, 2000. An interesting discovery that some terrestrial rocks have isotopic signatures previously thought belong just to meteorites was announced by chemists at the University of California, San Diego (or see here). They also mention that the UCSD discovery also suggests that planetary geologists need to be careful in interpreting the origin of oxygen-isotope anomalies on meteorites, since these signatures can occur in terrestrial as well as extraterrestrial rocks.

73. November 19, 2000. Info appeared in Russian press about mini-Tunguska in 40 km northwards from Ul'yanovsk city. About 10 000 sq. meters of a forest were affected at 17-18 UT(?), September 27, 2000. An eyewitness describes the event as follows.
There was a loud rumble. About 1 km from him a large black "tube" decended down the forest. There were luminous sparks inside the "tube". His electronic watches stopped and a car's headlights lighted out (batteries were discharged). The glowing "tube" disappeared, and something rattled more for some time. The sky, where the "tube" originated, became brighter (clearer?), clouds appeared.
The area is a circle 100 meters in diameter. Inside the circle grass is rumpled, trees uprooted. Some trees are not uprooted, but inclined, and their tops are broken off. Dogs and wild animals avoid the area. People also feel some discomfort in there. Strangerly, but batterflies were seen in there in November 2000. Radioactive level inside the circle is very low, compared with the nearby one.
A local meteorologist proposed that it was a tornado, adding that in November, 2000 there is an absolute maximum of atmospheric pressure in the region, but other local meteorologists rejected the tornado interpretation.
Unfortunately, the event is still practically non-investigated. I try to obtain more info on it and post them. (see the next pos.)

I should say that in the fall of 2000 many reports are coming about various "UFOs" in Russia. So at 1:45am MSK (22:45 UT, Nov.13) morning of Nov.14 a triangle fireball formation was seen in Dagestan(later addition: the occurrence of a strong earthquake near city of Baku on November 25, 2000 hints that the flying lights were precursors - earthquake lights).
On the night October 13/14 residents of village Zeledeevo (Yurga district, Kuzbass) saw as a large fire object swiftly moved to the ground. Many local services were on alert. Search was conducted for the whole night, and the next 2 days, but nothing were discovered.
And here is one more report.

74. November 21, 2000. There are some news about the Ul'yanovsk mini-Tunguska (see above). As I suspected that it was a geometeor, I requested a local investigator to check, aren't any tectonic faults, deposits, underground water in the place, and also, weren't any air-pressure changes on the date, and/or cloudiness increase on the next day. The result is the following: there is a tectonic fault indeed, and probably even intersection of two faults. Moreover, there are also mineral waters deposits! Cloudiness was almost complete already on the day of the event, but air-presuure on the next day had been changed (increased). In other words, all typical geometeor's geophysical circumstances were realized!

75. December 8, 2000. In December issue of Planetary And Space Science Vol. 48 (15) pp. 1447-1455 an article: "Discovery of probable Tunguska cosmic body material: anomalies of platinum group elements and rare-earth elements in peat near the Explosion Site (1908)" by Q.L. Hou, E.M. Kolesnikov, L.W. Xie, M.F. Zhou, M. Sun, N.V. Kolesnikova has appeared.
Here is its abstract:

Ten Sphagnum fuscum peat samples collected from different depths of a core including the layer affected by the 1908 Tunguska explosion in the Tunguska area of Central Siberia, Russia, were analyzed by ICP-MS to determine the concentrations of Pd, Rh, Ru, Co, REE, Y, Sr, and Sc. The analytical results indicate that the Pd and Rh concentrations in the event- and lower layers were 14.0--19.9, and 1.23--1.56 ppb, respectively, about 3--9 times and 3 times higher than the background values in the normal layers. In addition, the patterns of CI-chondrite-normalized REE in the event layers were much flatter than in the normal layers, and differed from those in the nearby traps. Hence, it can be inferred from the characteristics of the elemental geochemistry that the explosion was probably associated with extraterrestrial material, and which, most probably, was a small comet core the dust fraction of which was chemically similar to carbonaceous chondrites (CI). In terms of the Pd and REE excess fluxes in the explosion area, it can be estimated that the celestial body that exploded over Tunguska in 1908 weighed more than 10(in power 6) t, corresponding to a radius of >60 m . If the celestial body was a comet, then its total mass was more than 2*10(in power 7) t, and it had >160 m radius, and released an energy of >10(in power 7) t TNT.

77. January 2, 2001. There are strong evidences that the Dec.26 NSW Australian event was not caused by a "meteorite", but was a geophysical event.

78. February 15-16, 2001. Academician Vasil'ev Nikolai Vladimirovich died Feb.15 at 5 pm in Kharkov's hospital after a long illness.... He was a leader of Tunguska research since early 1960s.... The Tunguska research in many aspects was conducted due to his enthusiasm and energy. He has devoted his life to Tunguska...

Sometime ago, as foreseeing that he has not much time, Vasil'ev wrote his Memorandum, where he summarises results of Tunguska research. In Russian here are all 3 parts of it: www.irkutsk.com/tunguska/part1koi.htm);
www.irkutsk.com/tunguska/part2koi.htm);
www.irkutsk.com/tunguska/part3.koi.htm);
You can use on-line translator to read it.
Probably it is the first (and the last...) document, where Vasil'ev can say openly, ignoring demands of "science policy", what he thinks about Tunguska after being informal leader of Tunguska investigation for 4 decades. And he repeats several times in the Memorandum, that Tunguska doesn't match a stony meteorite or a comet... This is his conclusion after several decades of hard research...

79. April 27, 2001. There was a remarkable example of a geometeor's event in Jordan on April 18. Details see in my geophysical meteors www-page.

80. July 2, 2001. I am glad to announce that the Moscow part of the TUNGUSKA 2001 International conference successfully finished! For details see here.

82. July 21, 2001.One of the most respectable newspapers in the world - British THE TIMES published an article in his July 21 issue on the idea of gas outburst causing Tunguska, which was reported at TUNGUSKA 2001 International conference by Prof. W.Kundt.

82. July 26, 2001.There were several remarkable natural events in USA in July. Some of them probably were of geophysical origin, and are considered in geophysical meteors www-article.

83. November 1, 2001. On Nov.1 a seminar on Tunguska took place in Moscow. About a couple of dozens of Tunguska researchers were present from Moscow, and also from Novosibirsk, and Krasnoyarsk. Chairman of the seminar was, as usually, well-known astronomer and Tunguska researcher Dr. I.T. Zotkin, who was in his first Tunguska's expedition in 1958! Here you can see his photo (his and other photoes below are taken during the seminar by A. Ol'khovatov). Delivered reports were:
Dr. Bagrov: Could Tunguska meteorite be Encke comet? (see his photo). You can read his opinion ("hardly could be") in abstracts of Tunguska 2001 conference.
Prof. B.U. Rodionov (see his photo) delivered report on summary of Tunguska 2001 conference, and its expedition to Tunguska. He also explained why he thinks Tunguska was a terrestrial event.
Romeiko V.A. (see his photo) delivered a report on other group's trip to Tunguska in the summer of 2001.
Participants of the seminar also briefly mentioned the recent Italian's announcement that Tunguska problem is solved. A typical reaction of participants was a smile. I can just join in this... You apparently can understand why, if you read the the Italian article yourself to find out details of their 'solution'. By the way, in a couple of days after BBC posted the Italians announcement, an appeal was spread via Internet by one of the Italian Tunguska researchers:

  Dear Friends and Colleagues,
I am sorry to bother you with non-scientific problems, but in Italy we
are facing with serious and dramatic problems concerning the research.
Our Government has decided to cut fundings: this is now "usual" in
Western countries, but in Italy we have already a very low funding. A
further cut will be dreadful for our already poor research. In addition,
the Government wants to reduce the personnel of scientific institutions
and to cancel the National Research Council (CNR, Consiglio Nazionale
delle Ricerche). 
The Italian Association of PhDs (ADI; I am a member) has prepared a plea
to the Italian Chief of Government, Silvio Berlusconi, and several of
his ministers. You can find it at the web address (both in Italian and
in English):
http://www.dottorato.it/appellogiovaniricercatori/index.html
I will greatly appreciate if you can subscribe and spread the plea. We
have already collected more than 3000 subscriptions and, among them,
those of the Italian Nobel Prizes Rita Levi Montalcini and Renato
Dulbecco. 
Thank you again for your help in this difficult time for Italy.
Greetings,

Luigi 

PS: I apologize if you have already received this email.

84. November 5, 2001. In the last several weeks activity of Tunguska research seems to increase among Russian investigators, as well as worldwide. Maybe it is because that during this current hard world-political situation people try to pay more attention to 'evergreen' items?

85. February 13, 2001. In recently appeared Tunguska forum you can read my comments on Italian article (see also pos.83) in a post of January 3, 2002, and their reply in a post of January 4, 2002.

86. May 29, 2002. Despite that it is not directly related with Tunguska research, the event is worth to mention. An investigation of a very interesting case of a 'dive attack' giant ball lightning in Australia.

87. May 29, 2002. A special session on Tunguska event is being organized on a conference on natural catastrophes in Brunel University in London, UK (see: http://www.brunel.ac.uk/depts/geo/Catastrophes/ ). http://www.brunel.ac.uk/depts/geo/Catastrophes/special.html ). The date of the Tunguska session is September 1. If you are interested to take part, please, contact as soon as possible the conference organizer Prof. Suzanne A. G. Leroy suzanne.leroy@brunel.ac.uk

88. June 1, 2002. I just updated my www-page on geophysical meteors with analysis of the remarkable May 26, 2002 'purple' fireball pictured in Turkey (its photo below taken from http://www.100megsfree4.com/farshores/ufo02tur.htm ).

89. September 13, 2002. American SCIENCE, in September 13, 2002 issue (p.1803) published a note "More Theories on Tunguska", based on results of the Brunel conference in London (see pos.87). Also British magazine NEW SCIENTIST published an article "Did blast from below destroy Tunguska?" on the item in September 7, 2002 issue (p.14).

90. October 22, 2002. Announcement of Tunguska 2003 International conference. Administration of Evenkya decided to organize and hold an international conference on Tunguska in the summer of 2003. See for details and updates here.

91. June 26. Our conference "95th Anniversary of the Tunguska problem" (official title of "Tunguska 2003") is over. It was held in the State Astronomical Institute named after P.K. Sternberg, Moscow. There were 2 special days, when Tunguska enthusiasts came together and argued with each other... And as usually, they did not come to any consensus on "What Tunguska was".
While most of the time the conference was rather calm, the last hour of the conference was rather "hot", as there was a rather strong clash (fortunately, just verbal/oral) between several advocates of different "streams" inside "Tunguska comet fall".
On the first day of the conference, there was a special "possible geophysical origin of Tunguska" session, which attendance was about a half of the "meteorite explosion" one. I think that it is rather good result for being inside an astronomical institute/organization.
More details of the conference, including its program (in Russian) can be read here.

92. July 25. Info on the September 25, 2002 Vitim bolide.
I just returned from a press-conference held by Kosmopoisk leader Vadim Chernobrov on investigation and an expedition for traces of the September 25, 2002 Vitim bolide. The results are so intriguing that I decided to posted them here. Here is what Vadim with colleagues said at the conference and during talks with me after the conference. I am stressiing on factual aspects.
They discovered, what seems to be a forest-fall 6 by 10 km with a tree-burn in the center. Their interpretation is that here a shock wave from the spacebody explosion (at some altitude) touched the ground.
They also discovered some kms from the forest-fall an area of "impact" (it is their interpretation, as it is farther forward along a trajectory). The "impact area" is covered with "small craters". Vadim said that from local hunters accounts, it follows, that the forest fall was formed between aprox. mid-September to mid-October.
Two very important things. Vadim said that routine daily measurements of radioactivity in a settlement of Mama (~50-60 km from the forest-fall) showed 2-fold increase above background on September 26, and then returning to normal in a few days. Now radioactivity in the area is about normal. Vadim also said that local residents rejected that a glow/rays they saw several days after the event from the "fall area" could be an aurorae, as they well-aware what an aurorae looks like.
Water/snow in the epicentral area was bitter. Analysis in Novosibirsk showed that it was apparently due to large concentration of nitrogen oxides. Moreover, an analysis in a Moscow's lab showed that there are a large concentrations of tritium in the water "like in water of nuclear-powered electric station cooling ponds"!...

I also searched myself for some facts about the event. And here is what I have found.
There were several seismic stations in the the region. The closest was in Bodaibo - about 56 km away from a projection of the "satellite's last tracked point". It registered 2 small disturbances at times corresponding to arrival of acoustic waves travelling from the point to the ground, and then to the seismostation through the ground (the first disturbance), and the second disturbances corresponds to aerial/sound waves. Unfortunately, the recording was destroyed, as the disturbances were not like of local earthquakes. Other 4 seismic stations (200-300km away) did not show anything above background noise. So we see, that here the situation seems to be in an agreement with a typical large meteoroid (spacebody) entered the atmosphere.
Also if the above-mentioned forest-fall was produced by a shock wave (by the way, energy of the explosion would be ~ 10 times more powerful than derived from satellite data), it would produce a local earthquake of magnitude ~3-4 - but evidently it was not! And what about the tritium and the radioactivity?...
Apparently the press-conference, as well as the expedition's results has produced much more questions than answers... Now several other expeditions are in the area, and I hope that we will get answers very soon. Also I think that it would be very important to check satellite (SPOT, IKONOS, TERRA, NOAA, etc.) pictures to pinpoint the time of the forest-fall formation. The 6-by-10 km forest-fall apparently must be seen in the pictures. If it appeared before (of later) the event, so apparently the forest-fall had nothing to do with the event (coordinates "inside" the forest-fall are 58 deg 09 min N, and 113 deg 21 min E). But if it was formed at that time...
New data is needed to understand the event, and it is too early for any solid conclusions. The investigation continues!...

Addition of July 26: While thinking about possible origin of the tritium, I recalled that somewhere in the region several technological/peaceful underground nuclear explosions were conducted. Search for the data confirmed that indeed, there were 7 explosions about 400 km to the north of the "meteorite fall" place from 1976 to 1987. So could the tritium abundance and some other "radioactivity peculiarities" be an artefact of the explosions? I think that the idea should be checked.

93. August 24, 2004. On the "Tunguska alien spaceship discovery".
While I prefer to abstain from any comments having a little info, numerous mass-media publications on the item, and questions from readers of my www-page are forcing me to make a brief comment.
Whatever Lavbin's group discovered, I see some positive aspects of their activity:
- they show (with participation of rather respectable science-related organizations) that there are interesting areas in Siberia (which could be connected with the Tunguska event or not), which are worth to investigate even just for general scientific interest.
- And they (with their extraordionary claims) attract attention of general public to the unresolved Tunguska problem!

Here are some links below.
An article in English:
http://msnbc.msn.com/id/5686713
Lavbin group www-page is (in Russian):
http://tungus-bolid.krasu.ru/expeditions.php
Those who are interested to look at the satellite pictures of large forest-falls in Siberia could look at the article (in Russian, and the pictures in the article are clickable):
http://www.kcp.ru/tungus.html
Another article on the Tunguska "alien spaceship" with pictures (in Russian):
http://www.kp.ru/daily/23343/31365/

94. August, 2004 A seminar on so called "geophysical meteors" was held at Sandia National Laboratories, NM, USA. I took place at the seminar with my report on geophysical meteors's observational data and their probable relation with geophysical situation.

95. November 14, 2004 A new book on Tunguska is to be published soon: http://www.amazon.co.uk/exec/obidos/ASIN/1840466200/qid=1100192502/ref=sr_8_xs_ap_i1_xgl/202-4894116-1706250
(if the long www-link fails, please go to http://www.amazon.co.uk/ and then search for tunguska or Surendra in there.)
If you are interested, you could to the www-page and order the book right now, to get it as soon it is printed out.
I did not see/read any part of it, so I can't comment it. But I hope that as its author Surendra Verma is a subscriber of our Tunguska forum, so facts given in the book will be correct.
Update I looked through the book. It consists of: Introduction, 11 chapters, timeline (chronology of Tunguska), sources and futher reading section.
Now about my impression. To tell the truth, initially I didnot think that I can find anything interesting for me in the book. Indeed it is a popular book, and moreover written by a non-member of Tunguska research community. So I expected just some well-known general stuff, which I am already bored to read.
But when I began to read, I couldn't stop! Moreover I was even astonished by one thing which I read. On pp.184-185 a story which had been written in a book "Siberia: The New Frontier" by G.St. George is retold. And in there G.George, who spent most of his childhood in Siberia, recalls about a doctor who claimed to have visited the Tunguska epicenter a few months after the Tunguska event. And the doctor said some very peculiar things! Here I can say that there were roumors in Russia that an expedition was in the epicenter in about 1909 and saw some unusual things, but all numerous attempts by Russian Tunguska researchers to find any info in archives, mass-media, etc. failed. The info in the book confirms that the expedition was real indeed, and obtained some peculiar data! A key question is: can we rely on G. George's memoirs? It would be nice if somebody could find out more about the writer.
Till now the first scientific expedition which probably was in the forest fall are known to be the Shishkov's expedition (later Shishkov became a prominent Soviet writer). It was in 1911 and the expedition passed through the area by an accident even being unaware "what it is".
There are small "excursions" in the book, telling about astronomical and physical matters, etc. It helps to better understand it for those who are unaware or have forgotten some scientific facts.
Fortunately the book is not a popular retelling of scientific ideas and hypotheses, but shows them in coflicts and debates, as "truth is born in argue". So sometimes the book is like a detective story!
As in almost every book, some minor mistypes and mistakes have penetrated. Here are some of them which I would like to mention here, as well as to make some comments:
-p.4 The earthquake was not detected in St. Petersburg, just barographic (airpressure) disturbance;
-p.110. Later investigations points to absence of "Tunguska spacebody" substance in the Polar regions at least (see Meteoritics, v.30, pp.634-638 for details). In general for a reader who has a little experience in Tunguska a part devoted to search for Tunguska substance could appear a little bit discrepant. In one place articles are citated that some "Tunguska spacebody microparticles" were discovered already in early 1960s, and in other places citating of 1990s claims that "unlikely". So a reader could be puzzled with such twisting development. The reason is the following. After failing to find any fragments of the hypothetical Tunguska spacebody, the substance search moved to search for microparticles, which is rather complicated and often ambigous (moreover cosmic microparticles can be found almost everywhere), so even experts often confuse in this. Anyway, now a summary looks like follows. Till now most Tunguska researchers consider that there is no reason to claim that Tunguska spacebody substance was discovered.
-p.116. To my knowledge Lake Cheko was not discovered to be an ancient impact.
-p.237 I just propose to investigate the idea that the tritium abnormalities could be due to the underground nuclear explosions. I don't insist, I just propose to check.
These are all remarks I wanted to make. As I didnot peruse the book, so I can't completely exclude that there could be something more to remark, so if you find anything, please let me know.
I think that the book is worth of reading by those who are interested in Tunguska, as well as by science and nature lovers in general.

96. November 17, 2004. My article on Tunguska was just published in the international scientific journal EARTH MOON AND PLANETS. Here you can read its abstract. or read the full article as Adobe Acrobat pdf-file: EARTH MOON AND PLANETS, vol 93, N 3, pp.163-173.

97. June 23, 2007 News story just appeared ( http://www.skyandtelescope.com/news/8134097.html ) that Italian researchers published an article where they proposed that Lake Cheko (about 8 km form the epicenter of the Tunguska event) was formed by an impact of a fragment of 'Tunguska meteorite'! The article is here: http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-3121.2007.00742.x
Let me make some comments. The idea was already checked by Soviet/Russian researchers in the year ~ 1960. Their initial idea to research the lake was that a lot of local surface waters (headwaters) pass through the lake, so the lake's bottom should accumulate substance of the 'Tunguska meteorite' fallen over large area. They discovered the funnel shape of the lake's bottom, but failed to find any evidences that it was a meteorite crater. Arguments were the following: a) there is no any rim around the lake: b) Forest/trees around the lake is older than ~50 years old in general; c) a local resident (Evenk who huntered in the area) said that on the place of the lake there was a 'zabolochennaya luzha ' (swampy pool). So the idea was rejected by Sovet/Rissian researchers. Now the Italians are trying to recover it.
And of course neither Soviet/Russian researchers nor the Italians discovered any fragments/microparticles of the hypothetical 'Tunguska meteorite' despite large-scale digging of the bottom and the lake surroundings.
I can add that interrogations of local residents conducted in the early 1960s show that a path from Vanavara settlement to the area of Strelka-Chunya (which later became a settlement too) went through Lake Cheko.
So there is practically no chance of the 'sudden appearence' of the lake from a meteorite impact.
But what can't be ruled out is flooding of the lake, as local residents said about fountains of water from the ground and some flooding near the Tunguska epicenter in association the Tunguska event. By the way, for the 'geophysical Tunguska' interpretation the phenomena are explained as being due to tectonic activity (and are known in association with earthquakes).

Anyway, I hope that the article (which possibly will be promoted in mass-media) will help the Italian researchers to get finance/funds to come to Russia next summer and to celebrate 100th Anniversary of Tunguska! :)
UPDATE OF JUNE 29, 2007: An excellent research "when was Lake Cheko formed" just appeared by an US physicist Bill DeSmedt click here.
UPDATE OF JULY 13, 2007: Just discovered that several years early the Italian researchers presented a paper with rather opposite opinion:

http://www-th.bo.infn.it/tunguska/GasperiniSvalbard.pdf

L. Gasperini, F. Alvisi, G. Biasini, E. Bonatti, M. Di Martino, C. Morigi, G. Longo, M. Pipan, M. Ravaioli, F. Sacchetti, M. Sacchi, L. Vigliotti: Geophysical/sedimentological study of a lake close to the epicenter of the great 1908 Siberian (Tunguska) explosion.
7th Workshop of the ESF-IMPACT Scientific Programme: Submarine craters and ejecta-crater correlation. Svalbard (Norway), August 29th - September 3rd, 2001. In: Abstracts and Proceedings of the Norwegian Geological Society, 1, (2001), pp. 29-30

A preliminary analysis of the geophysical data and of some sediment cores indicate that the Lake Cheko is a young feature and its sedimentary infill record a major change in the environmental conditions, from 0.2 to about 1 m below the lake floor. Although the morphology of the lake is compatible with an impact origin, several sedimentological and biological proxies indicate that its formation pre-dates the 1908 event. The isotopic composition of the organic matter and the sediment geochemistry (major and trace elements), will help define the nature of the cosmic body that caused the 1908 Tunguska event.

98. December 19, 2007 There is a press-release http://www.sandia.gov/news/resources/releases/2007/asteroid.html on Sandia researcher Mark Boslough calculations of Tunguska. There are some computer's graphics, but there is practically no info on physical models on which the calculations are based!
I can say that the graphics resembled me the one in their calculations presented in 1995! And what I read (in his 1995 paper) on the sparse info about the models isnot convincing.
Moreover one of the calculations outcome was a proposal that satellites in orbits are in danger due to 'plumes' from rather small meteoroids ('meteorites')! (see the Boslough's abstract on Tunguska-96 conference here: http://www-th.bo.infn.it/tunguska/abstr3.html ).
Interestingly that several groups of researchers using 'the most advanced' computer calculations obtain rather different results! :)
But there is one point in which I could agree with Boslough - a strength of the forest is used to be overestimated indeed, but in reality it should be incorporated into calculations in much more complicated form than Boslough has done. In my opinion this would alter results of the calculations completely.

99. May 22 (with addition on May 27), 2008. Info on some conferences in Russia to commemorate 100-th anniversary of the Tunguska event is here.
Remarkably, that one the main outcomes of the Tunguska conference held in Tomsk on May 1-3 was: THE [TUNGUSKA] PROBLEM IS NOT RESOLVED. See detailed info in Russian here: http://hodka.net/news.php#250508 .
I can add that the participants of the Tomsk conference were top experts on Tunguska. Most of them spent many years (some even since 1959!) researching Tunguska. So the conclusion is very important, as their opinion values a lot.

100. June 11, 2008. My new book on Tunguska just appeared in Russian.

101. July 6, 2008. Tunguska anniversary is over.

After a week of the Tunguska anniversary I would like to share my impressions of it. The main outcome is that TUNGUSKA PROBLEM IS NOT RESOLVED. I can say that it is almost general consensus on it. For example, it was funny to me (while attending) the 'meteoritical' Tunguska conference in Moscow to listen how the conference's chairman was not glad with one report that it raises more questions that have given answers! And it is despite the report was strictly on the 'meteoritical' Tunguska. So even advocates of the 'meteorite' have to recognize that there are a lot of problems with meteoritical theory.

In desperate attempts to regain the situation the advocates announced the news stories about acid rain traces which support the meteoritical Tunguska (in their opinion). In reality the 'news' is already 10 years old: http://adsabs.harvard.edu/abs/1998P%26SS...46..163K
Moreover, the story disproves the meteorite idea in reality: if a lot of acid rains fell, so a lot of cosmic dust of the 'Tunguska spacebody' was to fall with the rains! But there is no cosmic dust!
Another remarkable aspect is that even those who are used to use 'Tunguska asteroid' as an example of the asteroid-impact-danger have to use it more cautiously: http://www.sun-sentinel.com/news/local/southflorida/la-sci-asteroid5-2008jul05,0,4035875.story
Just a couple weeks ago there would be no doubt in the 'Tunguska asteroid'.
So I think that the celebrations were very useful.

102. June 26, 2009. Cometary Tunguska again.

I think that many of you already read the news stories like these:
http://www.newscientist.com/article/dn17375
http://www.news.cornell.edu/stories/June09/TunguskaComet.html
I can say that in my opinion a good point is that the publications attract attention to a problem in cometary/asteroidal interpretations of Tunguska - the unusual sky phenomena. As it can be seen from the publications even the cometary interpretation needs some "new physics"! In other words, they wrote that Tunguska phenomenon can't be explained with just nowadays scientific knowledge (that is what I state for a long...).

Regarding the sky phenomena the situation is even more complicated. It is because some brightning of the sky was reported in England on the night 29-30 June, 1908. In other words - about simultaneoulsy with Tunguska (or even some hours before)! Moreover, there are some evidences, that similar but less-distinct sky phenomena occured even several days early!...

So in my opinion, we have still a long way to go to understand Tunguska especially in detail.

103. July 22, 2009. Some new data from from the Tunguska epicenter.

A rather interesting news story appeared in http://en.rian.ru/analysis/20090722/155587125.html
Here are just a few citiations from there:

A century later scientists still at odds on Tunguska Event explanation

More than 100 years have passed since the Tunguska Meteorite Event and the mystery of its occurrence remains unsolved, but scientists have not given up on solving the riddle. This July, an international research group from Italy and the United States ventured into deepest Siberia to investigate the most likely explanations of the mysterious event, and RIA Novosti correspondent David Burghardt joined them. ...
The two-week expedition included six professors from the University of Bologna, the University of Florence, and Cornell University.
... The researchers looked at two of the most probable theories: meteorite impact and volcanic gas vent explosion. The scientific expedition was divided into two camps, one at Lake Cheko, where they were researching the meteorite theory, and the other at Kulik’s Cabin near the epicenter (some 10 kilometers from the first group), where they were researching geological explanations for the blast.
... Four professors from the University of Bologna, Carlo Stanghellini, Maurizio Serrazanetti, Romano Serra, and Marco Cocchi, believe Lake Cheko was created by a meteorite impact due to its shape and tree growth in the area. The lake is elliptical (approximately 100 meters by 300 meters) rather than round, which is consistent with other lakes and swamps in the area. However, no impact ring or rim residue has been discovered at the lake, which would be noticeable had a meteorite created the lake. The native Evenki say that the lake has always been there and the name comes from the Evenki language meaning “dark waters.”
... All four of the Italian researchers at Lake Cheko believe the lake was created by one of three impacts in 1908: the first exploded in the atmosphere, the second struck the ground, creating Lake Cheko and changing the direction of the creek, and the third struck the ground further North at the epicenter, presumably creating several deep bogs. They agreed that the meteorite that created the lake would have been 1-5 meters in diameter and the tree growth around the lake proved that it was created in 1908.
... Jason Phipps Morgan, a geophysicist from Cornell University, and Paola Vanucchi, a geologist and geophysicist from the University of Florence, believe that the 1908 event was the result of a gas vent explosion created from the center of the earth. They did much investigation around the epicenter, especially what is called John’s Rock, which is a 10-12 ton rock formation that is free-standing. According to Morgan, this rock was actually “burped up” when the gas vent exploded, pushing the rock to the surface through a funnel. Morgan named the still unconfirmed funnel after his colleague, Paola’s Funnel. He noted that this rock is the only one of its kind in the area and is definitely of volcanic nature. The scientists collected some 30 kilograms of rock samples, especially quartz and quartzite, from and around John’s Rock, in search of shocked quartz, which would indicate that there was volcanic activity in the area.
Vanucchi said that some of the rock samples showed traces of being shocked, or fractured, and further research on the samples would be completed in both Italy and the United States. She also said that they believe they have found the main vent of the volcanic gas explosion very near to John’s Rock.
... Morgan said the amount of basalt in the area is so great that it proves the existence of constant volcanic activity for millions of years. Samples from the waterfall area were also taken for comparison with those from the John’s Rock location. Though lava has ceased to reach the surface, lava vents still exist and can build up pressure and blow, thus creating a blast like that in the epicenter.
...

104. August 1, 2009. A review of some recent publications on Tunguska.

I decided to review some recent publications on Tunguska from time to time.
I plan to review just publications which are interesing to me (usually these are ones which consider real Tunguska facts).
Today there are 2 such publications.

The first one is ( http://adsabs.harvard.edu/abs/2009Ge%26Ae..49..397G ):

Title:	
	Atmospheric discharge as a source of emission during the Tunguska disaster
Authors:	
	Gladysheva, O. G.
Affiliation:	
	AA(Ioffe Physical-Technical Institute, Russian Academy of Sciences)
Publication:	
	Geomagnetism and Aeronomy, Volume 49, Issue 3, pp.397-404
Publication Date:	
	06/2009

I didn't read the article, but I read other Gladysheva's publications on the matter. She inputs 2 new items into the Tunguska comet interpretation:
1) the Earth-ionosphere electric discharge after the event;
2) the cometary substance with some special properties.

I can say that I have a little against the electric discharge between the Earth and the ionosphere (moreover, the geophysical interpretation admits something similar), but I am very skeptical about the cometary substance. Anyway it is very remarkable that an advocate of the Tunguska comet has to propose the discharge to fit facts into the cometary explanation.

The second one is ( http://arxiv.org/abs/0907.1067 ):

Title: Cometary airbursts and atmospheric chemistry: Tunguska and a candidate Younger Dryas event
Authors: Adrian L. Melott (Kansas), Brian C. Thomas (Washburn), Gisela Dreschhoff (Kansas), Carey K. Johnson (Kansas)
(Submitted on 6 Jul 2009)

Abstract: We estimate atmospheric chemistry changes from ionization at the 1908 Tunguska airburst event, finding agreement with nitrate enhancement in GIS2PH and GISP2 ice cores and noting an unexplained accompanying ammonium spike. We then consider the candidate Younger Dryas comet impact. The estimated NOx production and O3 depletion are large, beyond accurate extrapolation. A modest nitrate deposition signal exists in ice core data. The predicted very large impulsive deposition might be visible in higher resolution data.
Ammonium has been attributed to biomass burning, and found coincident with nitrate spikes at YD onset in both the GRIP and GISP2 ice cores. A similar result is well-resolved in Tunguska ice core data, but the Tunguska forest fire was far too small to account for this. Direct input of ammonia from a comet into the atmosphere is consistent with the spike for the candidate YD object, but also inadequate for Tunguska.
An analog of the Haber process with hydrogen contributed by the cometary or surface water, atmospheric nitrogen, high temperatures, pressures, and the possible presence of catalytic iron from a comet could in principle divert a variable fraction of the reaction products to ammonia, accounting for ice core data in both events.

This research adds some new interesting facts in the Tunguska datafile. Everybody is allowed to download and read the research, so I just make a brief remarks.

- Authors accepted the speed of the Tunguska spacebody about 30 km/s. At such speed the spacebody unlikely to penetrate to low altitudes ~ 6 km unless it was exceptionally strong. But then it couldn't have been a comet!
- Here is an interesting fragment of the publication:

Using high-resolution GISP2H ice core data from the CODIAC archive at NCAR/EOL (Dreschhoff and Zeller, 1994; Dreschhoff, 2002) we find the enhancement over background in nitrate deposition for Tunguska. We first sum nitrate measurements at samples 2225-2227 (the associated peak) and then subtract background, which we assume is given by an average of 5 measurements preceding and following the three peak values. We find the net peak enhancement of 165 ppb. This is converted to a surface density by multiplying by the density and thickness of the ice/firn (600 kg m-3) giving 1.49 x 10-6 kg m-2.

To compute an equivalent value from the simulation results, we sum the rate at the 75 degree North latitude band over 90 days following the event, which gives a net peak enhancement value of about 1.50 x 10-6 kg m-2, in good agreement with the ice core result.

Anyway even such 'loose' approach failed to fit the data with ammonium, so the authors wrote:

Thus, all three candidate processes fail to explain the atmospheric chemistry record for the recent, and best understood, Tunguska event.

The Haber process for ammonia synthesis was developed for fertilizer and munitions during World War I. Under conditions of high temperature and pressure, atmospheric nitrogen and hydrogen (cometary ice) react to form ammonia.

The assumed mass of ice in the Tunguska comet is insufficient to synthesize sufficient ammonia to account for the ammonium ion in Greenland ice cores. However, it appears that at least one fragment impacted a swampy, partially melted permafrost area, the present site of Lake Cheko (Gasperini et al., 2008). Based on the size of the probable impact crater lake, sufficient water would have been present as a reactant to synthesize the ammonia.

105. June 29, 2010. An important new publication.

In my opinion very important article was published in 'Zapiski Rossiiskogo Mineralogicheskogo obschestva' (issue 1, 2010). Here is its abstract ( http://www.minsoc.ru/articles.php?id=32&mid=1391&eid=139107 ):

G. T. SKLUBLOV, YU. M. MARIN, S. G. SKUBLOV, B. F. BIDYUKOV, L. N. LOGUNOVA, V. V. GEMBITSKY, E. S. NECHAEVA.

GEOLOGICAL AND MINERALOGICAL-GEOCHEMICAL PECULIARITIES OF LOOSE SEDIMENTS AND PRIMARY ROCKS IN EPICENTER OF TUNGUSSKAYA CATASTROPHE IN 1908.

Comparative analysis of mineralogical-geochemical peculiarities of the pre-catastrophe and syncatastrophe loose sediments in epicenter of Tungusskaya catastrophe in 1908, their comparison with geochemical parameters of the principal types if primary rocks, materials of the cosmic photographic surveying, the new data on carboni- ferous spherules and radiocarbon dating allow to make the assumption about the Late-Pleistocene age (more than 100 thousand years) of starting the intensive cryptovolcanic activity in the area, about three stages in develop- ment of the Quaternary mud volcanism and multiple explosions of deep-level gases in Holocene (the Tungussky explosion is considered as the final event of this stage). The proposed cryptovolcanic model of Tungussky phe- nomenon may be useful in forecasting the placer diamondiferous potential of Siberian platform. Key words: Tungussky phenomenon, cosmophotographic-geological map, geochemical peculiarities of rocks, carboniferous spherules, mud volcanism, cryptovolcanic model.

In simple words it is written in the article that data on microparticles distribution in the Tunguska epicenter hints that the Kulikovsky paleovolcano was in some degree activated several times after his famous eruptions 250 million years ago. And the last 2 times the activation was about 2000 years ago and in 1908! Of cource these could be not large-scale lava eruptions, but some elevated degassings, for example.
If confirmed this could be a practical proof that Tunguska was not a 'meteorite/comet', but was terrestrial phenomenon!
Later addition: On the request of the author I post the article.

106. June 30, 2010. Some new Tunguska story in press.

A new theoretical work Tunguska is to appear soon in the forthcoming issue of respectable 'Doklady akademii nauk' journal (it is to be translated in English ( http://www.maikonline.com/maik/showIssues.do?juid=REO5NNYWR&year=2010 ) Authors of the forthcoming publication ( V. Gendugov, V. Natyaganov, and A. Chaika) proposed terrestrial explanation of Tunguska caused by hydrogen emanation from the Earth interior with follow-up explosive burning. Here is the associated news story (in Russ): http://rian.ru/science/20100630/251325581.html

107. December 14, 2010. More news on the 'terrestrial Tunguska'.

Here is Tunguska news story in German:
http://www.spiegel.de/wissenschaft/natur/0,1518,734266,00.html

Here is the abstract of the citated (in the story) report:

2010 Fall Meeting          
Cite abstracts as Author(s) (2010), Title, Abstract xxxxx-xxxx presented 
at 2010 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec. 

HR: 1340h
AN: V13C-2371 Poster
TI: Was the Tunguska 1908 event a late byproduct of a Permo-Triassic 
Verneshot?
AU: *Vannucchi, P 
EM: paola.vannucchi@unifi.it
AF: Earth Science Dept., Universita' di Firenze, Firenze, Italy
AU: Morgan, J P
EM: japhmo@gmail.com
AF: EAS Dept., Cornell University, Ithaca, NY, USA
AU: Andronicos, C L
EM: ca98@cornell.edu
AF: EAS Dept., Cornell University, Ithaca, NY, USA
AU: Della Lunga, D 
EM: damianodellalunga@alice.it
AF: Earth Science Dept., Universita' di Firenze, Firenze, Italy
AB: The Tunguska region is covered by ~1500 m of Siberian Traps basalts. 
The 1908 Tunguska event occurred in the Tunguska Great Depression which 
is part of a volcanic edifice, the Khushminskii Volcano, whose age is 
contemporaneous to the emplacement of the traps, i.e. about 250 Ma at 
the Permo-Triassic or Paleozoic/Mesozoic boundary. The Tunguska Great 
Depression is elliptical with a major axis of about 13 km. It has a 
crater-like morphology, with a central edifice, Mount Stojkovic (about 
500 m) rising 200 m above the rest of the central swamp. Mount Stojkovic 
is also at the 1908 Tunguska event epicenter calculated from treefall 
patterns. Outcrops at the summit of Mount Stojkovic expose quartzites 
and siliceous diamicrites. Other outcrops of quartzites are found a few 
km to the west of Mount Stojkovic. These sedimentary rocks are Permian 
fluvial deposits sedimented on the Siberian Craton before the eruption 
of the traps, and are now associated with volcanic pipes which cut 
through the trap basalts. Analysis of these quartzite samples reveals 
that they have been affected by shock metamorphism, as was first 
described by Hryanina (LPSC Abstracts, 1999). We were able to identify 
shocked quartz, toasted quartz, brecciated quartz crystals, 
pseudotachylites and rapid partial melting with spiky outgrowths of 
quartz and feldspars. The cause of the Tunguska 1908 event remains 
controversial. The main controversy is due to the fact that neither an 
obvious large impact crater nor any obvious extraterrestrial material 
has been found at this site; so that the extraterrestrial body is 
imagined to have exploded/vaporized about 8-10 km above the Earth’s 
surface. Such an air explosion could have not produced shock 
metamorphism. The recently proposed minor impact crater, lake Cheko, 
about 8 km NW of Mt. Stojkovic, still has trees in upright positions on 
its lakebed, so shock metamorphism would also be out of question here 
even if this were to be imagined as an impact-linked feature. At the 
same time, the probability that two extraterrestrial bodies would fall 
on the same point on Earth is 1 in 10,000 chance. Our preferred 
hypothesis is that the Siberian Traps, the Khushminskii volcano, the 
shock metamorphism and the Tunguska event are all linked together, and 
all caused by a terrestrial process related to hyperexplosive gas 
release from >50km depths in the Siberian Craton. 
DE: [3625] MINERALOGY AND PETROLOGY / Petrography, microstructures, and 
textures
DE: [3660] MINERALOGY AND PETROLOGY / Metamorphic petrology
DE: [8428] VOLCANOLOGY / Explosive volcanism
SC: Volcanology, Geochemistry, and Petrology (V)
MN: 2010 Fall Meeting

The report rises questions beyond Tunguska. Indeed till now the mentioned shock metamorphism is considered as an evidence of a space-impact (as 'there is no known terrestrial process to produce such large pressures'). And many large depressions on the Earth which were early assigned to 'volcanism' (or cryptovolcanism), were re-assigned during last decades to space-impacts just due to presence of the shock metamorphism. But the research undermines many of such re-assignments as it hints that there is such terrestrial process! So apparently scientists from the 'space-impact communnity' must check the report discoveries very carefully and if confirmed they have to re-evaluate the assignments. But I am afraid that they just prefer to ignore the research... Anyway let's look at the development.

108. September 9, 2011. An important new publication.

In my opinion very important article was published in 'Zapiski Rossiiskogo Mineralogicheskogo obschestva' (issue 3, 2011). Here is its abstract ( http://www.minsoc.ru/articles.php?id=34&mid=1403&eid=140311 ):

Skublov G. T., Marin Yu. B., Skublov S. G., Logunova L. N., Nechaeva E. S., Savichev A. A.

Mineralogical-geochemical features of primary rocks, loose sediments and catastrophic mosses in the Northern Swamp area (region of the Tunguska catastrophe in 1908)

Mineralogical-geochemical studies of primary rocks, loose sediments and catastrophic mosses carried out, for the first time, for one of areas in the Tunguska catastrophe region (1908), has allowed to distingu- ish 7 geochemical associations. The following elements have there the indicator meaning: Zr and Hf —with close level of accumulation in volcanites, talus deposits and the ash fraction of catastrophic mosses, which evidences the unique, terrestrial source of the substance; Rb, Pb, Cs — accumulated in clayey frac- tion of talus deposits; the group of petrogenetic (Ca), rare (Y, Sc, Sr, Ba), rare-earths (La-Lu) and ore-for- ming (Cu, Mo, U, Th) elements with the maximum contents in the ash fraction of catastrophic mosses. For these group elements the plutonic source is assumed connected possibly with the carbonatiteforming pro- cesses. Zonal distribution of REE has been determined in the ash fraction of catastrophic mosses, the half circle peripheric zone of the supposed crypto-volcanic chimney is characterized by the increased REE contents, and its central zone — by their decrease; by anomalous concentrations of arsenic there was map- ped the linear gas-emanating structure. Microprobe analysis of the catastrophic mosses material (plant remnants, ferruginous mosses, carbonic spherules, etc.) has revealed the wide spreading of the element-or- ganic compounds, numerous micron-scaled anomalies of light and heavy elements (Ti, Mn, Fe, Ni, Cu, Zn), and it correlates with data of G. Longo on micro-particles in resin of catastrophic trees. The assump- tion is made about possible gas composition of the plume which initiated the Tunguska catastrophe co- ming to the Earth’s surface from the seep mantle. Attention is focused upon importance of geological data in studying the Tunguska phenomenon.

On the request of one of the authors I post the article (in Russian with English abstract).

109. June 12, 2013. Some remarks on the news about possible discovery of the Tunguska meteorite remnants by Ukranian researchers.

For the news read: http://www.nature.com/news/rock-samples-suggest-meteor-caused-tunguska-blast-1.13163 http://dx.doi.org/10.1016/j.pss.2013.05.003

Those who read their original papers (in Russian) published in 1980s could hardly find any new great argument in their 2013 article.

After discovering the alleged 'Tunguska meteorite remnants' in the late 1970s by the Ukranian researchers it was promoted in the Soviet mass-media. But later it was realised that the announcement was too optimistic. Despite the researchers dug out and worked out many tonns of peat these were the only samples which could be suspected as a meteorite remnants (by the way the area near the Kulik's izba is not the best place for sample's taking due to strong human activity in there since 1920s resulting in possible contamination, etc.).
Since that times many more tonns were worked out by various Tunguska researches in various places but with permanently negative results...

And moreover even the sample's attitude to meteorite is still problematic.
Indeed let me citate the Ukranian researcher's 2013 article (as simple HTML can't reproduce some Greek letters, I changed them into English and the citation is from accepted manuscript):

(...)
However, Sobotovich et al. (1985) suggested that 
the diamond-lonsdaleite carbon allotropes enriched in diverse trace elements are 
products of the shock metamorphism of the terrestrial graphite available on the 
Earth’s  surface  during  the  Tunguska  blast  or  even  outside  the  context  of  the 
Tunguska event. 
Sobotovich at al. (1985) strongly strengthened their conclusions based on 
the  fact  that  the  Ir  concentration  (0.16  ppm)  in  the  Tunguska  diamond-
lonsdaleite-graphite  intergrowths  is  five  times  smaller  than  that  in  meteorites. 
Moreover, in support of Sobotovich et al.’s hypothesis, later Hough et al. (1995) 
confirmed  that  chemically  robust  carbon  particles  in  peat  from  the  Tunguska 
blast  area  do  not  contain  any  extraterrestrial  signatures,  because  their  isotopic 
signature  delta13C=-25‰,  and  delta15N=0‰  correspond  to  those  of  organic  matter. 

However, though all mentioned evidences are correct, some uncertainties remain 
in  Sobotovich  et  al.’s  interpretation  because  the  Ir  content  in  the  Tunguska 
diamond-lonsdaleite-graphite intergrowths is about 10 times larger than that in 
the terrestrial rocks. 

(...)
On  the  other 
hand, some controversial data, such as the low Iridium and Osmium contents, 
which  are  close  to  the  detection  limit,  the  presence  of  aragonite  and  a  light 
carbon (delta13C = -15.6 +/- 2‰) reservoir might suggest that the precursor of the 
studied Tunguska samples was terrestrial carbon material (graphite). Although 
the  delta13C  value  of  the  Tunguska  samples  is  similar  to  that  of  some  iron 
meteorites, e.g. graphite nodule of Kendall County hexahedrite (delta13C = -13.3 
to -14.50 ‰; Deines and Wickman, 1973, 1975), the negligible content of Os and Ir 
in the carbon matrix would support its terrestrial precursor. 

However, ignoring negligible contents of Ir and Os (which may be due to 
primary inhomogeneity), and taking into account the presence of native metal, 
sulfide and phosphide (e.g. troilite, taenite, gamma-iron and schreibersite) in diamond-lonsdaleite-graphite matrix, we conclude that the studied Tunguska samples are 
microscopically small remnants of a meteoritic body. 
(...)
For  additional  confirmation  of  the  meteoritic  nature  and  more  definite 
determination  of  the  meteorite  type,  investigations  of 
3He/4He ratio,  xenon isotopes (136Xe/130Xe and 129Xe/130Xe), noble gases, rear earth elements and PGE contents should be carried out. 
(...)

In other words:
Initially Ukranian researchers thought that they discovered the Tunguska meteorite remnants. But later some of them (as deceased in 2013 Emlen Sobotovich - by the way he is not among the authors despite the article was submitted in 2012) changed their mind. And the 2013 article is written by those who didnot change their minds.

As it is seen even from the text of the article even despite the new research the origin of the samples is still unclear.

Other important aspects of interpretation as of 'Tunguska meteorite' are:

- Despite titanic efforts searching through peat the samples were the only ones.
For comparasion: the 2013 Chelyabinsk meteorite which was much smaller than the hypothetical Tunguska one and had rather shallow trajectory and disintegrated much higher but still left a lot of remnants. In some areas its remnants were collected almost 'with bags' despite deep snow.
So having deal with such unique Tunguska samples it is hard to make far-going general conclusions...

- The area is in a peculiar place of the Earth.
I just want to remind that the Tunguska epicenter is in the center of a paleovolcano from former 'hot spot' of the Earth. The most powerful in the known history of the Earth volcanic activity took place 250 millions years ago in this region. The paleovolcano is a relatively loosely closed 'hole' leading to the Earth interiors. Moreover there are hints that volcanic degassing was increased in the paleovolcano in 1908 according to the publications of a Russian geologist G. Skublov...

Anyway the article is greeted as a research on Tunguska delivering some new data (independently of how the authors interpret the data).

110. January 19, 2017. Some comments on confirmation that the Cheko lake is older than Tunguska.

I can't say that it is the news for many Tunguska researchers as it was clear 'from the beginning'. Some retrospective on the Italian research ( proposing that the Cheko lake was formed by impact of a large fragment of the Tunguska meteorite ) you could read on this web-page (see pos. 17 and later).
Those who are interested in the original source of the news could read it here (in Russ.):
http://ec-rgo-sfo.com/novosti/1183-ozero-cheko-starshe-tungusskogo-meteorita

111. November 10, 2017. Again about probable Tunguska - associated fall-out.

Here is from:

--------------------

The time of abrupt change in CAR (from 22.3–244  g m? 2 y? 1), dust flux and several other proxies are noted 
in the modelled age of the 57–58 cm layer (cal AD 1882 ±  43–1920 ±  28) and is in good agreement with the date 
of the Tunguska cosmic body event (TCB) which happened in June 1908 (Fig. 2) and is the best known and most 
mysterious extra-terrestrial event recorded in Central Russia; the amount of cosmic material dispersed into the 
atmosphere has been estimated at ca 1 million tons 38,39 .
Indirect evidence of TCB-induced dust fallout in the Mukhrino peatland is an unusual occurrence of mullite 
in the “Tunguska layer” and its absence in adjacent layers (Supplementary Table 2). Mullite is a high-temperature 
phase that forms due to the decomposition and transformation of clay minerals at temperatures > 1100 °C 40 . The 
mineral, together with microspherules, scoria like objects (SLOs) and other high temperature minerals (corun-
dum, suessite) lacking in the ‘Tunguska layer’, has been deemed evidence of a Younger Dryas meteorite impact 41 . 
In the ‘Tunguska layer’, mullite may be a product of melting of dust and soil minerals at extremely high tempera-
tures induced by the TCB explosion. A distinct peak in microscopic charcoal contents (Fig. 4), indicative of dis-
tant fires, has been recorded in this layer together with an increased concentration of Se (Supplementary Table 1), 
a biogenic element released during forest fires 42 . It is known that the TCB impact set 2000 km 2  of taiga on fire. The 
main stream of dust formed during the TCB explosion passed westwards through Siberia, Europe and America 7 . 
As to the best of our knowledge, there were no local fires during this time in the vicinity of the Mukhrino peat-
land, it is proposed that post TCB fires could have influenced the dust flux and the element concentration in this 
peat layer. The layer is characterised by the highest Th/U value (3.9; Supplementary Table 1) which would indicate 
a change in the supply of natural dust.

I would like just to remind that the fire in the Tunguska epicenter was rather moderate comparing with numerous taiga fires which occur rather often. I think that it is a key to evaluate the idea that "In the ‘Tunguska layer’, mullite may be a product of melting of dust and soil minerals at extremely high temperatures induced by the TCB explosion."

Go to the A. Ol'khovatov Main Page in English: http://olkhov.narod.ru/tunguska/index.html