[S-SS06] 地震予知・予測

[SSS06-P06] Seasonal precipitation and winter dominance of earthquake activity along the northeastern coast of the Arabian Gulf

*Muhammad Usman¹、Hiroaki Takahashi、Kosuke Heki (1.Life and Environmental Science LES Department, Zayed University, Abu Dhabi, UAE)

キーワード：Earthquake, Seasonality, Shuster Test, North Eastern Arabian Gulf

The collision of the Arabian plate with the Eurasian plate causes compressional stress in the northeastern coastal areas of the Arabian Gulf and high seismic activity along the Makran subduction and the Biltis Zagros subduction zone. Here we use various earthquake catalogs to evaluate the seasonality of earthquake occurrences in this region. After confirming that the catalog is complete down to the magnitude of 4.5, we focus on earthquakes with a magnitude greater than or equal to 6 and remove aftershocks. The number of earthquakes in two-month bins suggests a gradual increase in earthquakes from summer to winter, with the peak in February and March. A statistical test indicates that the seasonality is significant at the ~94% confidence level, but we found it difficult to explain it with seasonal surface loading. High precipitation in this region during winter suggests the infiltration of water to seismogenic depths increases the pore pressure with a time lag of a few months and encourages earthquakes during this time of year.