Crustal structure and fluid distribution beneath the southern part of the Hidaka collision zone revealed by 3-D electrical resistivity modeling

Ichihara Hiroshi,Mogi Toru,Tanimoto Kengo,Yamaya Yusuke,Hashimoto Takeshi,Uyeshima Makoto,Ogawa Yasuo

Title	Crustal structure and fluid distribution beneath the southern part of the Hidaka collision zone revealed by 3-D electrical resistivity modeling
Creator	Ichihara, Hiroshi Mogi, Toru Tanimoto, Kengo Yamaya, Yusuke Hashimoto, Takeshi NRID 1000070283588 Uyeshima, Makoto Ogawa, Yasuo
Rights	An edited version of this paper was published by AGU. Copyright 2016 American Geophysical Union
Subject	NDC 450
Description	Other The Hidaka collision zone, where the Kurile and northeastern (NE) Japan arcs collide, provides a useful study area for elucidating the processes of arc-continent evolution and inland earthquakes. To produce an image of the collision structure and elucidate the mechanisms of anomalously deep inland earthquakes such as the 1970 Hidaka earthquake (M6.7), we conducted magnetotelluric observations and generated a three-dimensional resistivity distribution in the southern part of the Hidaka collision zone. The modeled resistivity was characterized by a high resistivity area in the upper crust of the Kurile arc corresponding to metamorphic rocks. The model also showed conductive zones beneath the center of the collision zone. The boundary between the resistive and conductive areas corresponds geometrically to the Hidaka main thrust, which is regarded as the arc-arc boundary. The correspondence supports the collision model that the upper-middle part of crust in the Kurile arc is obducting over the NE Japan arc. The conductive areas were interpreted as fluid-filled zones associated with collision processes and upwelling of dehydrated fluid from the subducting Pacific slab. The fluid flow possibly contributes to over-pressurized conduction that produces deep inland earthquakes. We also observed a significant conductive anomaly beneath the area of Horoman peridotite, which may be related to the uplift of mantle materials to the surface.
Publisher	American Geophysical Union
Date	Issued 2016-04-29
Language	eng
NIItype	journal article
Versiontype	VoR
Identifier	URI http://hdl.handle.net/2115/64582
Relation	isIdenticalTo DOI https://doi.org/10.1002/2015GC006222
Journal	ISSN 1525-2027 Geochemistry Geophysics Geosystems 17(4), 1480-1491
File	https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/64582/1/Ichihara_et_al-2016-Geochemistry%2c_Geophysics%2c_Geosystems.pdf (application/pdf)
Oaidate	2017-10-15T15:00:00Z