Laboratory experiments on fracture formation associated with slip propagation along a rock fault under heterogeneous stress

2015 Fiscal Year Final Research Report

• Project/Area Number: 26870912
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Solid earth and planetary physics; Geology
• Research Institution: Central Research Institute of Electric Power Industry
• Principal Investigator: Mizoguchi Kazuo 一般財団法人電力中央研究所, 地球工学研究所, 主任研究員 (50435583)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 断層 / 地震 / 滑り伝播 / 実験 / 割れ目

Outline of Final Research Achievements

Theoretical studies have suggested that fracture pattern developed along faults records rupture propagation direction of earthquakes. In order to investigate the damaging behavior of rocks with slip propagation, I conducted the experiments on spontaneous propagation of fault slip along a pre-cut rock surface. I observed several fault slip events where a slip nucleates spontaneously in a subsection of the fault and propagates to the whole fault. The rupture speed increased with increasing stress applied on the fault. However, the maximum speed is about 2.4m/s, much lower than the S-wave velocity of the rock. The slip events were not earthquake-like dynamic rupture ones. The observation of the rock specimens after the experiments showed no formation of microcracks along the fault. This might be due to the much slower rupture speed and its associated low stress drop of the slip events. More efforts are needed to reproduce earthquake-like slip events in the experiments.

Free Research Field

構造地質