Research by Project Researcher. Yusuke Yamashita et al. was published in “Science”



Research by Project Researcher. Yusuke Yamashita et al. was published in “Science”

Science 8 May 2015: Migrating tremor off southern Kyushu as evidence for slow slip of a shallow subduction interface (Abstract/Full text/Reprint)


Y. Yamashita1,*,†, H. Yakiwara2, Y. Asano3, H. Shimizu1, K. Uchida1, S. Hirano2, K. Umakoshi4, H. Miyamachi2, M. Nakamoto1, M. Fukui1, M. Kamizono1, H. Kanehara5, T. Yamada6, M. Shinohara6, K. Obara6

1Institute of Seismology and Volcanology (SEVO), Faculty of Sciences, Kyushu University
2Nansei-Toko Observatory for Earthquakes and Volcanoes, Graduate School of Science and Engineering, Kagoshima University
3National Research Institute for Earth Science and Disaster Prevention
4Graduate School of Fisheries Science and Environmental Studies, Nagasaki University
5Faculty of Fisheries, Nagasaki University
6Earthquake Research Institute (ERI), The University of Tokyo



Detection of shallow slow earthquakes offers insight into the near-trench part of the subduction interface, an important region in the development of great earthquake ruptures and tsunami generation. Ocean-bottom monitoring of offshore seismicity off southern Kyushu, Japan, recorded a complete episode of low-frequency tremor, lasting for 1 month, that was associated with very-low-frequency earthquake (VLFE) activity in the shallow plate interface. The shallow tremor episode exhibited two migration modes reminiscent of deep tremor down-dip of the seismogenic zone in some other subduction zones: a large-scale slower propagation mode and a rapid reversal mode. These similarities in migration properties and the association with VLFEs strongly suggest that both the shallow and deep tremor and VLFE may be triggered by the migration of episodic slow slip events.


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