CHARACTERISTICS OF 2017 HOJEDK EARTHQUAKE SEQUENCE IN KERMAN PROVINCE, SOUTHEAST IRAN

Abstract

Kerman province in southeast Iran, has experienced historical and instrumentally recorded earthquakes. In December 2017, three destructive earthquakes have occurred around Hojedk, in Kerman within 11 days. In this study, first the regional seismotectonics and seismicity is presented. Then, the source mechanisms of main shocks are modeled and the results are compared with the active faults and seismicity pattern is discussed. Moment tensor inversion in time domain is used to obtain the source mechanism of earthquakes. The results indicate that the mechanisms of main shocks and aftershocks are mainly reverse and are in agreement with the trend of tectonic forces as well as the mechanisms of other earthquakes. The epicentral distribution of aftershocks indicates two clusters. The spatial distributions of clusters are in agreement with the epicentral distribution of main shocks. The cluster around the first earthquake in EW cross section has a length 15-20 Km, while the cluster around the second and third has a length about 20-25 Km. The Hojedk earthquakes occurred along the northern extension of previous earthquakes where a kind of seismic gap could be observed and still exists. In 1972, within five days four earthquakes with magnitudes 5.5 to 6.2 occurred in Sefidabeh region in eastern edge of Lut block. In both regions earthquakes have reverse mechanisms and associated with surface ruptures. Thus, it could be concluded that the energy was mainly released with several moderate earthquakes in adjacent faults. In northern extensions of both regions, seismic gaps still could be observed and major earthquakes might occur in future.