Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

S (Solid Earth Sciences ) » S-SS Seismology

[S-SS14] Fault Rheology and Earthquake Physics

Wed. May 29, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Keishi Okazaki(Japan Agency for Marine-Earth Science and Technology), Hideki Mukoyoshi(Department of Geoscience Interdisciplinary Graduate School of Science and Engineering, Shimane University), Hiroyuki Noda(Kyoto University, Disaster Prevention Research Institute), Keisuke Yoshida(Tohoku University)

[SSS14-P16] Effect of Wear Process on Earthquake Recurrence

*Jeen-Hwa Wang1 (1.Academia Sinica)

Keywords:Earthquake, Recurrence, Slip, Friction, Viscosity, Wear

Earthquake recurrence is studied from the temporal variation in slip through numerical simulations based on the normalized form of equation of motion of a one-body spring-slider model with thermal-pressurized slip-weakening friction and viscosity. The wear process, whose effect is included in the friction law, is also taken into account in this study. The main parameters are the normalized characteristic displacement, Uc, of the friction law and the normalized damping coefficient (to represent viscosity), η. Define TR, D, and tD to be the recurrence time of events, the final slip of an event, and the duration time of an event, respectively. Simulation results show that TR increases when Uc decreases or η increases; D and tD decrease with increasing η; and tD increases with Uc. The time- and slip-predictable model can describe the temporal variation in cumulative slip. When the wear process is considered, the thickness of slip zone, h which depends on the cumulated slip, S(t)=ΣD(t), i.e., h(t)=CS(t) (C=a dimensionless increasing rate of h with S) is an important parameter influencing TR and D. Uc is a function of h and thus depends on cumulated slip, ΣU, with an increasing rate of C. In the computational time period, the wear process influences the recurrence of events and such an effect increases with C when C>0.0001. When viscosity is present, the effect due to wear process becomes stronger. Both TR and D decrease when the fault becomes more mature, thus suggesting that it is more difficult to produce large earthquakes along a fault when it becomes more mature. Neither the time-predictable model nor the slip-predictable one can describe the temporal variation in cumulative slip of earthquakes under the wear process with large C.