SCEC2021 Plenary Talk, Earthquake Geology

Coseismic surface rupture: insights from field and satellite observations

Ryan Gold

Oral Presentation

2021 SCEC Annual Meeting, SCEC Contribution #11119
High-resolution satellite observations provide unprecedented constraints on surface-rupturing earthquakes, yielding detailed insight into the patterns of localized and distributed faulting extending multiple kilometers across the rupture zone. Field-based investigations of modern surface-rupturing earthquakes typically focus within 10s of meters of the primary fault zone and complement satellite observations, offering the capacity for rapid response, the detection of subtle and/or minor surface faulting, and the ability to ground-truth remotely sensed results. Furthermore, coseismic field-based investigations replicate the lens through which we view prehistoric fault rupture patterns and estimate geologic slip rates. In this presentation, I argue that the combined analysis of field and satellite observations in modern ruptures yield complementary insights. That is, we cannot rely on remote sensing or field studies alone. In this review of recent (last 20 years) surface-rupturing earthquakes, with an emphasis on the 2019 Ridgecrest, CA Mw6.4 and Mw7.1 earthquakes, I demonstrate how paired satellite and field-based investigations can be used to quantify the distribution of localized (“on-fault”) and distributed (“off-fault”) surface deformation. I explore the potential impacts of distributed faulting on geologic investigations of prehistoric ruptures, surface-displacement distributions from single and multiple events, and Quaternary geologic slip rate investigations. I also consider the downstream impacts of distributed faulting on probabilistic fault displacement hazard analysis (PFDHA) and probabilistic seismic hazard analysis (PSHA).