Local time dependence of earthquakes occurrence and its possible connection with geomagnetic diurnal variations

Abstract

ABSTRACT Occurrence of earthquakes is not only controlled by internal processes such as the tectonic processes, but also by external ones as Sun-Earth system processes. The aim of the current study is to examine the distribution of earthquakes occurrence at some active seismic regions in order to determine the dominant period of earthquakes occurrence with respect to local time and its possible connection with geomagnetic diurnal variations. Analyzing long-term datasets from 1986 to 2020 demonstrated that the occurrence of earthquakes at the studied regions is strongly depending on local time where earthquakes tend to occur more often during noon local time. This behavior is in somehow similar to the pattern of geomagnetic diurnal variations. Therefore, the study was extended to investigate the probable correlation between both of them. Diurnal variation of North-South geomagnetic component (X-component) was examined and compared with the local time distribution of earthquakes at each region. Data analysis revealed a significant correlation between the geomagnetic diurnal variations and earthquakes occurrence. Thus, the results support the idea of existence a dominating time interval of earthquakes occurrence and also a relationship between local time dependence of earthquakes and geomagnetic diurnal variations that may help in earthquakes prediction in the future.