COLLABORATIVE FIELD AND REMOTE SENSING RESPONSE FROM THE 2019 RIDGECREST EARTHQUAKE SEQUENCE

The 2019 Ridgecrest earthquake sequence spurred rapid field reconnaissance by teams of geologists in the Ridgecrest Rupture Mapping Group (Kendrick et al., 2019, SCEC). Field mapping was complemented by analysis and interpretation of remotely sensed satellite data, which was publicly disseminated via social media and other channels. The remote sensing techniques, including optical pixel tracking and InSAR, facilitated rapid identification of potential surface-rupturing fault strands for field verification. We show how the field response in the weeks following the earthquakes was aided by remotely sensed products and describe the advantages and drawbacks of field vs remote-sensing observations. We find that rapidly generated remote sensing products allow identification and broad characterization of fault slip sense and amount over large areas, but remotely mapped fault traces often oversimplify details of deformation observed in the field or can be confused with lineaments unrelated to deformation. A weakness of purely field-based mapping is that features like wide shear zones are easily identified and mapped in the field, but total fault displacement can be difficult to measure compared to satellite-based displacement estimates. Far-field fault strands (located hundreds of meters or more from the principle rupture) can be missed entirely without remote-based maps to guide field teams. Recent advances in remote sensing technology and its application, which facilitate comparison of mapped faults, earthquake geomorphology, and surface rupture behavior, have changed the methods, sequence, and focus of earthquake response investigations.

Abstract is co-authored with the RIDGECREST EARTHQUAKE WORKING GROUP: Stephen Angster USGS, Seattle; Benjamin Brooks USGS, Menlo Park; Timothy Dawson, CGS, Menlo Park; Chris DuRoss, USGS, Golden; Todd Ericksen, USGS, Menlo Park; Ryan Gold, USGS, Golden; Nick Graehl, CGS, Sacramento; Elizabeth Haddon, USGS, Menlo Park; Janis Hernandez, CGS; Kenneth Hudnut, USGS, Pasadena; Jessica Thompson Jobe, USGS, Golden; Katherine Kendrick, USGS, Pasadena; Devin McPhillips USGS, USGS, Pasadena; Alex Morelan CGS, Sacramento; Brian Olson, CGS, Los Angeles; Jason Patton CGS, Sacramento; Belle Philibosian, USGS, Menlo Park; Kate Scharer USGS, Pasadena; Gordon Seitz, CGS; Eleanor Spangler CGS, Sacramento; Brian Swanson, CGS, Los Angeles; Michael DeFrisco, CGS.