Yesterday, 27 July 1999, a radar relief of the Cheko lake is carried out, in order to reconstruct the stratigraphy of more superficial layers (the top two meters of the lake bed).
Several reliefs are done from land, by means of a new method (at multiple cover), that allows to get informations about the physical characteristics of materials and to calculate, with precision, the wave speed in the soil.
Land and lake reliefs will be linked during the analysis, in order to locate the discontinuities, calibrated from core boring done in the lake, and of great interest in the study of the Tunguska event.
Land reliefs have also the purpose of studying the permafrost (soil layer always frozen) that, according to first reliefs, it is at a mean depth of about 50 cm. The link with lake reliefs will allow to locate the possible continuation of the discontinuity soil/permafrost also in the Cheko lake.
A total of 28 cores have been extracted from the bottom of the lake, that will be analyzed in italian labs. We think that we have completely carried out the schedule of "in situ" works planned for the Tunguska99 Scientific Expedition.
Today, we pack scientific instruments and camp equipment in order to load the helicopter Mi-26, that will bring the expedition to Krasnoyarsk tomorrow. The expedition will continue to Moscow with an Il-18D. We plan to arrive in Forli' on friday 30 July at 11 local time (more or less two hours).
See some photos from Tunguska!
Bologna, 28 July 1999
For the Tunguska99 Press Office