"Details Emerging on Tunguska Event Impact Crater May 2008",
May 2008 Blogtech.oc9
http://blogtech.oc9.com/index.php?option=com_content&view=article&catid=22:la-terre--the-earth&id=206:20080525tunguska&Itemid=21

Details Emerging on Tunguska Event Impact Crater.

Йcrit par #space_on_irc.freenode.net (Dusty)   

Lake Cheko in Siberia has been noted as the probable crater of the 1908 Siberian Tunguska event. This news was covered and discussed in December, but details on the crater were scant. Now a new paper written by Luca Gasperini, Enrico Bonatti, and Giuseppe Longo ( the same team in Bologne, Italy that made news in December) has a horde of new details on the supposed crater.

The team visited Lake Cheko complete with their own catamaran and completed ground penetrating radar maps, side-scanning sonar images, aerial images, and some sample collection of Lake Cheko. Interestingly, they also imaged an object under the sediment that may be a fragment of the impacting body. lot more details are available in paper including images, side-scanning sonar image, a 3-d view of the lake, a morphobathymetric map, and various proposals of ideas. It's an interesting read, these dudes are good. They plan to return this summer and drill the core if weather permits, hopefully answering the question once and for all.