phys.org - Research team claims to have found evidence Lake Cheko is impact crater for Tunguska Event By Bob Yirka.
May 21, 2012 phys.org/news/2012-05-team-evidence-lake-cheko-impact.html Comment:
When I was child I became fascinated by this event after the first time I heard of it. I remember that one of the first computer programs I ever "wrote" was the copy of a short one that came in a newspaper to calculate the expected frequency and energy released by the impact of meteoroid ans comets of different sizes. Research article:
- Gasperini L et al. Magnetic and seismic reflection study of Lake Cheko, a possible impact crater for the 1908 Tunguska Event.
Geochemistry, Geophysics, Geosystems, Vol. 13, Q05008, 12 pp., 2012. doi:10.1029/2012GC004054 (May 12, 2012) agu.org/pubs/crossref/2012/2012GC004054.shtml Abstract
A major explosion occurred on 30 June 1908 in the Tunguska region of Siberia, causing the destruction of over 2,000 km2 of taiga; pressure and seismic waves detected as far as 1,000 km away; bright luminescence in the night skies of Northern Europe and Central Asia; and other unusual phenomena. This “Tunguska Event” is probably related to the impact with the Earth of a cosmic body that exploded about 5–10 km above ground, releasing in the atmosphere 10–15 Mton of energy. Fragments of the impacting body have never been found, and its nature (comet or asteroid) is still a matter of debate. We report here results from a magnetic and seismic reflection study of a small (∼500 m diameter) lake, Lake Cheko, located about 8 km NW of the inferred explosion epicenter, that was proposed to be an impact crater left by a fragment of the Tunguska Cosmic Body. Seismic reflection and magnetic data revealed a P wave velocity/magnetic anomaly close to the lake center, about 10 m below the lake floor; this anomaly is compatible with the presence of a buried stony object and supports the impact crater origin for Lake Cheko.
The following aren't real pictures, probably a representation of the orography without the water of the lake and the surrounded trees by Luca Gasperini (University of Bologna):
----------------------- Related informative articles: scientificamerican.com - The Tunguska Mystery
(5 pages) By Luca Gasperini, Enrico Bonatti and Giuseppe Longo.
May 19, 2008 scientificamerican.com/article.cfm?id=the-tunguska-mystery geotimes.org - Long-lost Siberian crater found?
(1 page) By Sadie MacMillan.
February, 2008 www.geotimes.org/feb08/article.html?id=nn_crater.html
URL source post: plus.google.com/102953679072375185491/posts/6wSgjvzqYSa