Определение параметров исторических землетрясений по макросейсмическим данным

Abstract

The paper attempts to determine the main parameters of historical earthquakes of the Carpathian region based on macroseismic data, using the macroseismic field equation, indirect parameters, and complex comparison with modern earthquakes. So far, the main source of information about the parameters of historical earthquakes in the Carpathian region has been "New catalog of strong earthquakes ...". In this catalog, all parameters are defined very ap-proximately, with a wide range of values. In addition, over the forty-year period since the release of the catalog, the initial macroseismic data of Carpathian region earthquakes have been substantially replenished and re-evaluated using the MSK-64 macroseismic scale. The study determined such basic parameters of historical earthquakes as the macroseismic epicenter, the intensity at the epicenter, focal depth, and magnitude. As well as additional parameters: direction of the maximum macro-seismic effect, area of intensity zones, distance, and azimuth to the extreme point where the earthquake was felt. The earthquake parameters were calculated using the attenuation formula of the macroseismic field with coefficients obtained by the R.Z. Burtiev for intermediate earthquakes of the Vrancea zone of the Carpathian region, separately in four azimuthal ranges. For crustal earthquakes, the general Blake-Shebalin macroseismic field equation was used. Despite possible errors associated with a correct assessment of intensity at observation points, as well as the accuracy of the coefficients of the macro-seismic field equation used for specific seismic events, it was possible to determine the type of each historical earthquake and obtain more accurate values of their parameters. The re-fined parameters of historical earthquakes will allow making a more holistic picture of the seismic hazard in the Carpathian region.