Improvement of geoelectrical resistivity structures around Philippine Sea plate boundary beneath Shikoku distric

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540454
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Kochi University
• Principal Investigator: MURAKAMI HIDEKI 高知大学, 自然科学系, 教授 (10166259)
• Co-Investigator(Kenkyū-buntansha): YAMAGUCHI Satoru 大阪市立大学, 理学(系)研究科, 教授 (70191228) ; SHIOZAKI Ichiro 鳥取大学, 工学(系)研究科, 准教授 (80221290)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 四国 / フィリピン海プレート / 比抵抗 / 低周波微動 / ネットワークＭＴ

Outline of Final Research Achievements

This study aims to improve accuracy of geoelectrical resistivity structures around Philippine Sea plate boundary beneath Shikoku district, especially central and western Shikoku district, using the Network-magnetotelluric (MT) method. We determined MT response functions in the period range of 100-10000s at several observation sites in Shikoku district. In central Shikoku the comparison between the observed MT response functions and the theoretical MT response functions calculated from 2-dimensional resistivity structures indicated the possibility of the resistivity structure similar to that under the eastern Shikoku, which has lower resistivity lower crust , lower resistivity oceanic crust and high resistivity plate. In the western Shikoku a lower resistivity (~10ohm-m) area at depth of 30-40km, which is corresponding to the region in which non-volcanic low-frequency tremors occur, was found newly.

Free Research Field

地球電磁気学