[IYAS9YAS]

From the picture, it appears there are trees growing on it, counter to the accompanying story.

[cripplecreek]

The story is written to make it appear more mysterious than it really is. Some samples could tell you whether it was volcanic or meteoric.

[cripplecreek]

Its made of limestone which rules out volcanic and meteor. It appears to be little understood but one theory is that its rock pushed up by underground gas.

http://en.wikipedia.org/wiki/Patomskiy_crater

[ApplegateRanch]

Yes; there are some trees; no, the rocks don't look volcanic. Google Earth has the area slightly blurred, probably to keep Russia pacified, though there are many photos available.

According to studies of Siberian scientists, the crater formed during the 300-350 years since the end of the beginning of the 15th or 16th centuries. The zoning of the crater caused by geological processes and intensive introduction of deep gas flows of matter, which led to the transformation of silicate rocks within the crater. "An important confirmation of these ideas were the result of s geophysics from St. Petersburg (SB State University of Mining) and Yekaterinburg (Institute of Geophysics, UB RAS). Performing gravimetric and geoelectrical investigations in a professional manner, they also came to the firm conviction that Patom crater has a depth of an endogenetic nature ", – said Antipin. source

From this, I infer the gist of the matter is that it was an earth fart, rather than either a volcanic or cosmic event.

A gassing event would explain many, if not all, of the reported sicknesses, avoidances, and deaths.