Examination of tectonic relationships between heterogeneous slow slip behaviors and forearc deformation in the Nankai subduction zone

2015 Fiscal Year Final Research Report

• Project/Area Number: 24340122
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: Kanazawa University
• Principal Investigator: Mizukami Tomoyuki 金沢大学, 自然システム学系, 助教 (80396811)
• Co-Investigator(Kenkyū-buntansha): HIRAMATSU Yoshihiro 金沢大学, 自然システム学系, 教授 (80283092) ; ENDO Noritaka 金沢大学, 自然システム学系, 助教 (60314358) ; WALLIS R. Simon 名古屋大学, 環境学研究科, 教授 (30263065)
• Co-Investigator(Renkei-kenkyūsha): MATSUSHI Yuki 京都大学, 防災研究所, 准教授 (90596438) ; ARAI Shoji 金沢大学, 自然システム学系, 教授 (20107684)
• Project Period (FY): 2012-04-01 – 2016-03-31
• Keywords: プレート境界 / スロースリップ / 地殻変動 / 蛇紋岩

Outline of Final Research Achievements

Slow slips at subduction boundaries are considered to be critical in stress build-up on the megathrust zones. We examine petrological controls on the mechanism and heterogeneous distribution of slip sources using multidisciplinary approaches including structural geology, geophysics and geomorphological chronology. The following results on the Nankai subduction zone will be an important step for practical understanding of slow slip phenomena: Layered structures of antigorite serpentinite formed through open system crust-mantle interaction show an exponential scaling relationship similar to deep low frequency tremors (DLFTs); The lateral variation in gravitational anomaly and scaling relationship between duration and amplitude of DLFTs can be explained by variable extents of serpentinization consistent with the present thermal structure of the Nankai region; Water separation ages successfully constrain the development of the Shimanto River system in response to the plate coupling.

Free Research Field

構造地質学