ИСТИНА

The work presents the results of analysis of the spatial distribution of repeated shocks. The data from the USGS/NEIC world catalogue of earthquakes from 1973 to 2014 are used. Short time intervals are considered - no more than 10 hours after the main shock, and the distance from the epicenter of the main shock - up to 5 degrees. The dependence of the number of repeated shocks on the distance from the epicenter was studied. Two properties of spatial distribution of repeated shocks have been noted. The first property is that the maximum of the curve describing the spatial distribution is observed at a certain distance (approximately from 10 to 120 km) from the epicenter of the main shock. Moreover, the logarithm of this distance is directly proportional to the magnitude of the main shock. The second property is that the position of the maximum does not depend on time, i.e. it is a stable spatial characteristic of the earthquake focal zone. Based on these properties, a new way of determining the characteristic size of the focal zone is proposed. The work was supported by the project of the RFBR 18-05-00096, as well as the states assignment programs of the IPhE RAS.