Spatial and Temporal Features in Diurnal Distributions of Strong Earthquakes at the Garm Research Area

Abstract

The spatial pattern of diurnal variations in the temporal sequence of relatively strong earthquakes in the Garm Research Area in Tajikistan for 1955–1991 has been investigated. The earthquakes that occurred in the daytime and at night, as well as the value characterizing their difference, have been mapped separately. The differences in diurnal seismicity variations in a few local zones have been discussed. Compact areas with major daytime seismic events presumably related to quarry explosions have been identified. They are located far beyond the Garm Research Area at a considerable distance from the network of seismic stations. The sources of man-induced seismic events have not been found within the Garm Research Area. The identified large connected areas combine the cells dominated either by day or night earthquakes.