Ryo Kurihara, Kazushige Obara, Akiko Takeo, Yusaku Tanaka :Earthquake Research Institute, The University of Tokyo, Tokyo, Japan <\/p>\n\n\n\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nDeep low\u2010frequency (DLF)\nearthquakes occur at depths of 10\u201330 km beneath the Kirishima volcanoes, which\nis one of the most active volcanoes in Japan. In the last decade, two major\nseries of eruptions were observed there. The relationship between DLF\nearthquakes and volcanic activity such as eruptions is still unknown;\ntherefore, we conduct two analyses, namely, relocation and detection to obtain\nthe precise spatial distribution and comprehensive temporal distribution of DLF\nearthquakes based on waveform correlations. The result is that DLF earthquakes\noccurred in some small clusters, having been activated for approximately 2\nyears from December 2009, during which various styles of eruptions including\nsubplinian eruptions on 26\u201327 January 2011 occurred (Figure). The long\u2010term\nincrease in DLF earthquakes was well correlated with crustal deformation\nbecause of the volume change of the magma reservoir. Most DLF earthquakes\nassociated with the 2011 eruptions are distributed in four deeper clusters that\nare different from those of DLF earthquakes in the other time periods.\nMoreover, the clusters were switched 3 times, which approximately correlates\nwith the transitions of eruption styles. These results suggest that DLF\nearthquakes were triggered by fluid flow in the deep crust related to the\neruptions.\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"