Magnetic and seismic reflection study of Lake Cheko, a possible impact crater for the 1908 Tunguska Event

• Published in: Geochemistry Geophysics Geosystems
• Main Authors: Gasperini, L., Cocchi, L., Stanghellini, C., Stanghellini, G., Del Bianco, F., Serrazanetti, M., Carmisciano, C.
• Other Authors: Gasperini, L.; CNR-Ismar Bologna, Cocchi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Stanghellini, C.; INAF-Bologna, Stanghellini, G.; CNR-Ismar Bologna, Del Bianco, F.; CNR-Ismar Bologna, Serrazanetti, M.; CNR-Ismar Bologna, Carmisciano, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, CNR-Ismar Bologna, Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, INAF-Bologna
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2012
• Subjects: Tunguska; Lake Cheko; Central Siberia; Impact cratering; magnetometry; seismic reflection; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods; 04. Solid Earth::04.04. Geology::04.04.04. Marine geology; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies; taiga; Siberia
• Online Access: http://hdl.handle.net/2122/8039; https://doi.org/10.1029/2012GC004054

A major explosion occurred on 30 June 1908 in the Tunguska region of Siberia, causing the destruction of over 2,000 square km 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. Published Q05008 3.4. Geomagnetismo JCR Journal restricted