A Simple Spring-Mass-Dashpot Model for Slow Earthquakes on a Viscous Fault

Rachel C. Lippoldt, & Charles G. Sammis

Submitted August 14, 2017, SCEC Contribution #7669, 2017 SCEC Annual Meeting Poster #195

One and two dimensional spring-mass-dashpot models are used to simulate the propagation of slow events in a viscous fault zone that is pinned by an array of asperities. The asperities fail at stress thresholds that lie within a prescribed range. The propagation velocity depends on the “waiting time” at an asperity, which depends on the ratio of fault-zone viscosity to fault zone thickness and on the range of asperity strengths. For physically reasonable values of wall-rock elasticity we can simulate propagation velocities in the observed range of 10 to 100 km/h using values of (viscosity)/(fault zone width) in the range of 10^10 to 10^12 and a two order of magnitude range of threshold strengths. Other observed characteristics of slow events such as repeating slow earthquakes and reverse propagation can be simulated on the 2D model when the asperities heal and are reloaded by surrounding slip.

Citation
Lippoldt, R. C., & Sammis, C. G. (2017, 08). A Simple Spring-Mass-Dashpot Model for Slow Earthquakes on a Viscous Fault . Poster Presentation at 2017 SCEC Annual Meeting.


Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)