Geological and geophysical system "tectonicsseismicity" of the unique Khailinsk center of high-magnet swarm. South-west of the Koryak seismic belt

Abstract

The Khailinsk Center is a unique phenomenon in the Koryak seismic belt, which frames the Beringia lithospheric plate in the north. It was created by a swarm of Khailinsk and Olyutorsk earthquakes and aftershocks with M = 5.0-7.6. The center lies in a submerged block of the lithosphere of the Olyutor Bay, created by interblock northwestern faults on the sides of the trough with a depth of 82 km in the relief of the lithosphere. Sea terranes with a maximum deflection of the lithosphere horizons in their keels, through which a column with earthquake hypocenters passes, are thrust onto the trough. The high-magnitude swarm of earthquakes of the Khailinsk Center has mutually orthogonal ellipses of aftershocks at common epicenters of the main shocks. The Khaili earthquake did not show the tradition of connecting the aftershock relaxation ellipse with the known aftershock geology in plan and section. Such powerful events that are not tied to an obvious geological structure seem an obvious novelty in world mining practice. An analysis of the Khailinsk and Olyutor events revealed a collision of two facts: the coincidence of the epicenters and the complete orthogonality of the clouds of both earthquakes. Their study as elements of one system “tectonics-seismicity” determined the geological space of the hypocenters position. The interest in the seismicity of the Khailinsk high-magnitude center is considered as an appeal in the geology of the outskirts to the unique small lithospheric plate Beringia in the seismology of NE Asia. The research basis of the tectonics-seismicity system is the concept of seismogenic tectonics in the territory of the active margin of the North Asian continent and the place of the Khailinsk Center for High Magnitude Swarm (KHC). The basics of such understanding of the seismicity in the outskirts of the territory tectonics are determined by the author’s “Concept of the block-key structure of the lithosphere on the active outskirts of the continent”. The epicentral region of the Khailinsk and Olyutorsk earthquakes is localized on the area of the local Tylgovyamsk Depression, connected to the Vyvensk Depression from the south on its hanging SE wing of the Vyvensk Fault zone.