11:00 AM - 11:15 AM
[SSS10-06] Quantitative analysis of seismicity in Japan dynamically triggered by teleseismic earthquakes
Keywords:dynamic triggering , teleseismic earthquake, seismicity in Japan, triggering intensity
Dynamic triggering (far-field triggering) of earthquakes is a natural phenomenon in which large surface waves from large earthquakes remotely trigger other earthquakes due to stress perturbations by passing surface waves. The dynamic triggering of earthquakes due to many large earthquakes has been reported by previous studies, but further investigation into quantitative analyses on the dynamic triggering is
required to elucidate the triggering mechanism.
In this study, changes in the seismicity rate in the Japanese Islands associated with distant earthquakes are quantitatively evaluated using the triggering intensity n (van der Elst & Brodsky, 2010). The n-value indicates the fractional seismicity rate changes before and after the arrival of surface waves from distant earthquakes, where n larger than 0 and n smaller than 0 mean the increase and decrease in seismicity rate, respectively. We use teleseismic events of M6 or greater from the ANSS Earthquake Catalogue and
regional earthquakes in the Japanese Islands from the JMA earthquake catalog (shallower than 20 km in depth, M2 or greater). The n-value for every grid area is calculated based on the method by van der Elst and Brodsky (2010). The distribution of n-values for seismic activity in 2020 shows extremely large positive values close to 1.0 around Lake Shikotsu in Hokkaido, near the Miyako Islands in Okinawa Prefecture and near the coast of Iwate Prefecture. There is no clear relationship between the distributions of the n-value and those of seismicity and volcanoes.
required to elucidate the triggering mechanism.
In this study, changes in the seismicity rate in the Japanese Islands associated with distant earthquakes are quantitatively evaluated using the triggering intensity n (van der Elst & Brodsky, 2010). The n-value indicates the fractional seismicity rate changes before and after the arrival of surface waves from distant earthquakes, where n larger than 0 and n smaller than 0 mean the increase and decrease in seismicity rate, respectively. We use teleseismic events of M6 or greater from the ANSS Earthquake Catalogue and
regional earthquakes in the Japanese Islands from the JMA earthquake catalog (shallower than 20 km in depth, M2 or greater). The n-value for every grid area is calculated based on the method by van der Elst and Brodsky (2010). The distribution of n-values for seismic activity in 2020 shows extremely large positive values close to 1.0 around Lake Shikotsu in Hokkaido, near the Miyako Islands in Okinawa Prefecture and near the coast of Iwate Prefecture. There is no clear relationship between the distributions of the n-value and those of seismicity and volcanoes.