Construction of the Average Curve of the Seismic Velocity of the Crust in the Territory of Armenia from Profile Seismic Observation Data

Abstract

To determine the coordinates of earthquakes, the Republic of Armenia (RA) Seismic Survey uses algorithms based on the Geiger method. All these algorithms use only one travel time curve (one velocity curve) for the entire study area and all stations of the RA seismological network. Despite the fact that a number of studies have been devoted to the structure of the crust and upper mantle of the Caucasus and, in particular, the RA, however, so far most of the existing travel time curves cannot be used to determine earthquake hypocentral coordinates and, in particular, the depth of the source with sufficient accuracy. Quite obviously, to determine the coordinates of earthquakes, it is desirable for the crust to have travel-time curves (or velocity columns) constructed not according to local earthquake data, but other seismological data, in particular, deep seismic sounding (DSS) and earthquake converted wave method (ECWM), and for the upper mantle, according to data on distant earthquakes. Currently, information has been collected on longitudinal wave velocities in the crust within the territory of Armenia, which makes it possible to present an averaged velocity model of the crust in Armenia. For this, the data of all available velocity sections were used, compiled from materials obtained along the network of regional profiles by ECWM and DSS data. The velocity curve was constructed from DSS and ECWM data obtained in different years in the territory of Armenia. The use of one velocity curve by the seismological networks in Armenia will make it possible to obtain homogeneous data from these networks.