Accelerating creep as a precursor of stick-slip-instabilities and the problem of prediction of earthquakes

Speaker: Valentin Popov
Earthquakes can be considered as a result of frictional instabilities in the fault system of tectonic plates. Similar instabilities can be easily reproduced and investigated in detail under laboratory conditions. In the presented work a simple tribological system with pronounced stick-slip motion has been studied experimentally as a model of earthquake. Observation of the movement of the body with resolution of 8 nm shows that during the entire stick phase, there is a slow creeping motion which quickly accelerates near the slip phase. This creeping motion is regular enough to serve as a basis of prediction of the moment of instability. We have shown that the entire movement of the specimen including both the accelerating creep and the rapid slip can be very good described using the rate and state dependent friction law by Dieterich. The last part of creeping motion immediately preceding the instability has a universal character and allows predicting with high precision the moment of the slip-instability. Generalizations to multi-body systems are discussed as well as to real tectonic systems are discussed