摘要：The MJMA7.3 Kumamoto earthquake occurred on April 16, 2016, in the western part of Kyushu, at a depth of 12 km,
on an active strike-slip fault. Here, we report on a relatively widespread activation of small remote earthquakes, which
occurred as far as Hokkaido, detected by analyzing the continuous waveform data recorded at seismic stations all
over Japan. Such relatively widespread remote seismicity activation, following a large inland earthquake, has not been
reported before for Japan. Our analysis demonstrates that the remote events were triggered dynamically, by the passage of the surface waves from the Kumamoto earthquake. Most of the remotely triggered events in the Tohoku and
Hokkaido regions, as well as close to Izu Peninsula, occur at or close to volcanoes, which suggests that the excitation
of crustal fluids, by the passage of Rayleigh waves, played an important triggering role. Nevertheless, remote activation in other regions, like Noto Peninsula, occurred away from volcanoes. The relatively large-amplitude Love waves,
enhanced by a source directivity effect during the Kumamoto earthquake, may have triggered seismicity on local
active faults. The dynamic stresses in the areas where remote activation has been observed range from several kPa
to tens of kPa, the thresholds being lower than in previous dynamic triggering cases for Japan; this might relate to
a change in the crustal conditions following the 2011 M9.0 Tohoku-oki earthquake, in particular at volcanoes in NE
Japan.
关键词：Kumamoto earthquake; Remote triggering; Volcanoes; Active faults; Dynamic stresses
