Structure of the Central part of the Kuril Trench according to new magnetic data

Speaker: Nikolay Palshin
“The central part of the Kuril Trench is also known as an atypical tectonic unit where the existence of the extension structures was suggested in 1980-ies. The anomalous behavior of the Kuril Sliver is usually explained by oblique subduction. The central part of the Kuril Trench is known as a “closed” seismic gap. Before the gap was closed two expeditions of the RV “Akademik M.A.Lavrentiev” (37 cruise in 2005 and 42 in 2006) had been carried out in the framework of the project «Studies of structural peculiarities of a seismic gap in the central part of Kurile-Kamchatka Island Arc as a possible source of a great earthquake and tsunami». Large amount of magnetic data was collected during these two expeditions.

In the period of September-October 2010 another expedition of the RV “Akademik M.A.Lavrentiev” (54 cruise) was carried out. Besides other geological and geophysical studies the scientific program of the cruise included continuation of the detailed magnetic survey in the Kuril Trench forearc region, which was started in 37 and 42 cruises.

The analysis of the magnetic data obtained during the cruises as well as from available magnetic data from public sources has been done and a combined magnetic map has been constructed. The combined map was used for tectonic interpretation based on spatial spectral technique. The results obtained confirm the atypical tectonic structure of the Kuril Sliver. Besides, convincing evidence has been found proving the modern tectonic activation.”