Influence of rapid healing induced by fault sintering on Earthquake cycles

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05645
• 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: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: TANIKAWA Wataru 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(高知コア研究所), 主任研究員 (70435840)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 焼結 / 地震 / 透水性 / 断層

Outline of Final Research Achievements

To evaluate the effects of sintering of fault rock by coseismic sliding on mechanical process, we carried out two experiments, such as (1) permeably tests during friction test underwater saturated condition, and (2) very rapid heating test. Our result show that it was the frictional heating is suppressed in the fluid saturated environment, so that the sintering phenomenon does not easily occur. On the contrary, the sintering can occur at above 1200℃ under dry condition where the powder particles adhere to each other. It was also found that the water permeability of the fault increases with increasing slip velocity. In addition, it was found that since the permeability after slipping will recover to the initial value suddenly. Therefore, these effects can influence on the seismic cycle model that considers the increase in fluid pressure.

Free Research Field

岩石物性

Academic Significance and Societal Importance of the Research Achievements

地下深部に破壊震源がある地震は、地震時に断層内で発生する物理化学的な現象を直接観察することができない。そのため、本研究は地震現象を模擬した岩石実験を通して、深部の断層の内部物理的な素過程から地震発生プロセスの理解に努めた。本研究では特に、鋳造やセラミック加工など産業と関わりの深い「焼結」に焦点を当てたことにより、地震現象を生活に密接な現象の一部だと見立てて考える学問の幅を広げることができた。得られた知見は、将来、地震発生数値模擬実験で利用される物理モデルの一部に利用され、より現実的な地震の発生規模や発生頻度を推定につながることが期待される。