@article{eb26d3f54ebc423eaa0646362c1f52cf,
title = "Precise relocation of low-frequency earthquakes in Northeast Japan: New insight into arc magma and fluids",
abstract = "High-resolution (~10-20 km) P- and S-wave velocity (Vp, Vs) tomography of the crust and uppermost mantle is determined to relocate precisely a large number of low-frequency earthquakes (LFEs) which occurred in Hokkaido and Tohoku during 2002-2016. The LFEs and seismic tomography are combined to study the arc magma and fluids in the study region. We divide the 4036 LFEs in Hokkaido and 4946 LFEs in Tohoku into 43 groups. Most of the LFEs are located in or around low-Vp, low-Vs and high Poisson's ratio anomalies beneath active arc volcanoes, which indicate the existence of abundant fluids and magmatic activities in the crust and uppermost mantle beneath the volcanoes. Our results also reveal the influence of large crustal earthquakes on the spatial and temporal distributions of the LFEs. Many of the LFEs occurred at edges of the low-Vp and low-Vs zones within ~15 km of the active volcanoes, indicating transportation and/or cooling of the arc magmas.",
keywords = "Seismic tomography, Seismicity and tectonics, Subduction zone processes, Volcano seismology",
author = "Xiongwei Niu and Dapeng Zhao and Jiabiao Li",
note = "Funding Information: We thank the Hi-net data centre and the JMA unified earthquake catalogue for providing the high-quality data used in this study (http://www.hinet.bosai.go.jp). The volcanic activity data are downloaded from the JMA website (http://www.jma.go.jp/en/volcano). We thank Drs Aiguo Ruan, XiaodongWei, Zhiteng Yu and Xinyang Wang for thoughtful discussions. This work was partially supported by research grants from the JSPS (Kiban-S 23224012) and the MEXT (26106005) to DZ, the (QNYC201601) and NSFC (41506048) to XN, and the National Program on Global Change and Air-Sea Interaction, SOA (No. GASI-GEOGE-01) and MOST of China (No. 2016YFC0600402) to JL. Most of the figures were made by using GMT (Wessel & Smith 1998). Prof Egill Hauksson (the editor), Dr Naofumi Aso and an anonymous referee provided thoughtful review comments which have improved this paper. Funding Information: We thank the Hi-net data centre and the JMA unified earthquake catalogue for providing the high-quality data used in this study (http://www.hinet.bosai.go.jp). The volcanic activity data are downloaded from the JMA website (http://www.jma.go.jp/en/volcano). We thank Drs Aiguo Ruan, Xiaodong Wei, Zhiteng Yu and Xinyang Wang for thoughtful discussions. This work was partially supported by research grants from the JSPS (Kiban-S 23224012) and the MEXT (26106005) to DZ, the (QNYC201601) and NSFC (41506048) to XN, and the National Program on Global Change and Air-Sea Interaction, SOA (No. GASI-GEOGE-01) and MOST of China (No. 2016YFC0600402) to JL. Most of the figures were made by using GMT (Wessel & Smith 1998). Prof Egill Hauksson (the editor), Dr Naofumi Aso and an anonymous referee provided thoughtful review comments which have improved this paper. Publisher Copyright: {\textcopyright} The Authors 2017. Published by Oxford University Press on behalf of The Royal Astronomical Society.",
year = "2018",
month = feb,
day = "1",
doi = "10.1093/gji/ggx445",
language = "English",
volume = "212",
pages = "1183--1200",
journal = "Geophysical Journal International",
issn = "0956-540X",
publisher = "Oxford University Press",
number = "2",
}