THE TUNGUSKA METEORITE: A DEAD-LOCK OR THE START OF A NEW STAGE OF INQUIRY? ? Part I by Academician N.V. Vasilyev from the TunguskaEvent Website There were five explosions, the second seeming to have been the most powerful. Light flashes followed at an interval of a few seconds and were seen at different spots of the sky. The last, fifth explosion, took place far in the north, somewhere near the Taymura river. Trees began to fall and the fire began after the first explosion, while the Evenks were in their tents, the latter being thrown down. There were traumatized people. The data communicated by I.M.Suslov are quite detailed and enable the whole phenomenon to be estimated as lasting no less than 20-25 seconds. However, there have been revealed in the area of the catastrophe some biogeochemical elemental and iso-topic anomalies which may be related to the event under discussion [42?47]. Interpretation of these anomalies is still more complicated since the epicenter of the Tunguska explosion almost ideally coincides with the center of an ancient volcano (click image right) [48], whose lava flows and thermal ejections undoubtedly affected essentially formation of the biogeochemical situation in the region. The structure of the forest fall area in the immediate vicinity of the epicenter also proved strange. Firstly, the assumption of the absence of radial tree falling here is not true. Surface observations [82] evidence that there are some leveled trees in this area as well, and the general radial character of the forest falling is seen up to a "special point", viz. the geometric center of the fallen forest area, as calculated by V.G.Fast [17 ]. Secondly, Kulik's interpretation of the fallen forest area on the basis of the large-scale aerophotography of 1938 not only corroborated the complex vector structure of the epicentral area, but also enabled assumption of the existence there of at least two or three subepicenters [ 83 ]. Thirdly, the vector structures of the forest falling on hill-sides facing the epicenter and the opposite ones are essentially different, which is in poor agreement with the assumption of the center of generation of the blast wave located high above the earth. Thus, the conclusion suggests itself that along with great energy release 5.5-8 km above the earth, there were a number of low-altitude (maybe even right above the surface) explosions that contributed to the total picture of destruction. This seems to be sustained by other data concerning in particular the configuration of the zones of dead trees ("poles") [84] in the central part of the area of the catastrophe and deposition of aerosols immediately after the explosion.