Large Earthquakes and Creeping Faults

Ruth A. Harris

Published March 1, 2017, SCEC Contribution #7189

Faults are ubiquitous throughout the Earth‘s crust. The majority are silent for decades to centuries, until they suddenly rupture and produce earthquakes. With a focus on shallow continental active-tectonic regions, this paper reviews a subset of faults that have a different behavior. These unusual faults slowly creep for long periods of time and produce many small earthquakes. The presence of fault creep and the related microseismicity help illuminate faults that might not otherwise be located in fine detail, but there is also the question of how creeping faults contribute to seismic hazard. It appears that well-recorded creeping fault earthquakes of up to magnitude 6.6 that have occurred in shallow continental regions produce similar fault-surface rupture areas and similar peak ground shaking as their locked fault counterparts of the same earthquake magnitude. The behavior of much larger earthquakes on shallow creeping continental faults is less well known, because there is a dearth of comprehensive observations. Computational simulations provide an opportunity to fill the gaps in our understanding, particularly of the dynamic processes that occur during large earthquake rupture and arrest.

Key Words
creeping faults, earthquakes, ground motions, fault creep

Harris, R. A. (2017). Large Earthquakes and Creeping Faults. Reviews of Geophysics, 55(1), 169–198. doi: 10.1002/2016RG000539.

Related Projects & Working Groups
Dynamic Rupture Code Validation, FARM, Ground Motions