Ring-shaped seismicity structures, being formed prior to large earthquakes with different mechanisms within intracontinental regions
Category: 14-1
UDC 550.34
Yu.F. Kopnichev(1), I.N. Sokolova(2)
(1) Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
(2) Institute of Geophysical Research, NNC RK, Alma-Ata, Kazakhstan
Abstract
We have been studying seismicity characteristics prior to 54 shallow large and great earthquakes with different mechanisms, which occurred within intracontinental regions. It was established, that ring-shaped seismicity structures within depth range of 0–33 km were formed prior to large interplate earthquakes. Such the structures were not revealed prior to large intraplate earthquakes. It was shown, that ring structure sizes (L) and also threshold magnitude values (Mt) essentially depend on the earthquake mechanism. We have obtained correlation dependencies for L and Mt values on magnitude of the major events. We suppose that a nature of ring-shaped structures is connected with deep fluid migration.
Keywords: attenuation, focal mechanism, ring-shaped seismicity structures, deep-seated fluids.
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