Establishment of quantitative models for growing and shrinking processes of continental crust by using forearc basins

2022 Fiscal Year Final Research Report

• Project/Area Number: 19KK0356
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (A))
• Allocation Type: Multi-year Fund
• Research Field: Geology
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Noda Atsushi 国立研究開発法人産業技術総合研究所, 地質調査総合センター, 研究企画室長 (50357745)
• Project Period (FY): 2020 – 2022
• Keywords: 沈み込み帯 / 付加体 / アナログ実験 / 地震

Outline of Final Research Achievements

From March 28th to November 30th, I stayed at the University of Lille, France, and conducted research on the analysis of acoustic survey records in the forearc region off the coast of Peru and the construction of a reproduction model of the subduction zone using a new analog experimental device. . Experimental results show that (1) normal accretion is a periodic process with a constant wavelength, during which the rate of coupling between the cladding and the cladding at the plate boundary under the accretionary complex changes spatiotemporally; (2) the wavelength of the accretionary period is preserved even if the number of weak layers in the accretionary deposit increases, but the geological structure and fault network within the accretionary complex become more complex; It was clarified that when there is a discontinuity in the layers, the wavelength of the accretionary period is disturbed, and the activity of the out-of-order thrust fault becomes conspicuous.

Free Research Field

地質学

Academic Significance and Societal Importance of the Research Achievements

本研究は、巨大地震の発生が予想されるプレート沈み込み帯において、付加体がどのように発達するのか、断層の活動度はどう変化するのかなどについてを検討したものである。この研究の主な成果は、付加体内やプレート境界における力のかかり方が付加体の成長過程に応じて変化することを示したことである。つまり、付加体の成長過程の段階に応じて、地震の発生しやすさが変化することを示しており、現在の沈み込み帯における地震活動の理解にとって重要な知見となる。