Microseismicity of the Persian Gulf and the Zagros Mountain Massif According to Bottom Seismological Observations

Abstract

Bottom seismological observations in the Persian Gulf over a short period made it possible to detect weak earthquakes with magnitudes (ML = –0.2–2.9), whose sources are located in the mantle under its water area and under the Zagros mountain range. On the section built across the coastline of the Persian Gulf, under the Zagros Mountains, the projections of the sources of the detected earthquakes form seismic focal layers, steeply dipping into the mantle to the northeast to depths of 120–180 km. The spatial distribution of strong and medium earthquakes, obtained from the updated earthquake catalog of the US Geological Survey and the ISC International Seismological Catalog, does not contradict the distribution of sources of micro- and weak earthquakes, but complements it, forming a separate seismic focal layer. According to the data obtained as a result of bottom seismological observations, the entire thickness of the earth’s crust of the region and the upper mantle, and not only the upper layers of the crust, as presented in a number of publications, are seismically active. It is possible that collision processes and accompanying phenomena (mantle seismicity and destruction of the granitic layer of the earth’s crust) are associated with the presumed presence and rotation of the earth’s surface with the center of rotation in the area of about. Cyprus.