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Liquefaction and Related Ground Failure from July 2019 Ridgecrest Earthquake Sequence

Zimmaro, Paolo and Nweke, Chukwuebuka C. and Hernandez, Janis L. and Hudson, Kenneth S. and Hudson, Martin B. and Ahdi, Sean K. and Boggs, Matthew L. and Davis, Craig A. and Goulet, Christine A. and Brandenberg, Scott J. and Hudnut, Kenneth W. and Stewart, Jonathan P. (2020) Liquefaction and Related Ground Failure from July 2019 Ridgecrest Earthquake Sequence. Bulletin of the Seismological Society of America, 110 (4). pp. 1549-1566. ISSN 0037-1106.

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The 2019 Ridgecrest earthquake sequence produced a 4 July M 6.5 foreshock and a 5 July M 7.1 mainshock, along with 23 events with magnitudes greater than 4.5 in the 24 hr period following the mainshock. The epicenters of the two principal events were located in the Indian Wells Valley, northwest of Searles Valley near the towns of Ridgecrest, Trona, and Argus. We describe observed liquefaction manifestations including sand boils, fissures, and lateral spreading features, as well as proximate non‐ground failure zones that resulted from the sequence. Expanding upon results initially presented in a report of the Geotechnical Extreme Events Reconnaissance Association, we synthesize results of field mapping, aerial imagery, and inferences of ground deformations from Synthetic Aperture Radar‐based damage proxy maps (DPMs). We document incidents of liquefaction, settlement, and lateral spreading in the Naval Air Weapons Station China Lake US military base and compare locations of these observations to pre‐ and postevent mapping of liquefaction hazards. We describe liquefaction and ground‐failure features in Trona and Argus, which produced lateral deformations and impacts on several single‐story masonry and wood frame buildings. Detailed maps showing zones with and without ground failure are provided for these towns, along with mapped ground deformations along transects. Finally, we describe incidents of massive liquefaction with related ground failures and proximate areas of similar geologic origin without ground failure in the Searles Lakebed. Observations in this region are consistent with surface change predicted by the DPM. In the same region, geospatial liquefaction hazard maps are effective at identifying broad percentages of land with liquefaction‐related damage. We anticipate that data presented in this article will be useful for future liquefaction susceptibility, triggering, and consequence studies being undertaken as part of the Next Generation Liquefaction project.

Item Type:Article
Related URLs:
URLURL TypeDescription
Zimmaro, Paolo0000-0002-3544-5961
Nweke, Chukwuebuka C.0000-0002-8939-571X
Hernandez, Janis L.0000-0001-8603-5500
Ahdi, Sean K.0000-0003-0274-5180
Goulet, Christine A.0000-0002-7643-357X
Brandenberg, Scott J.0000-0003-2493-592X
Hudnut, Kenneth W.0000-0002-3168-4797
Stewart, Jonathan P.0000-0003-3602-3629
Additional Information:© 2020 Seismological Society of America. Manuscript received 17 January 2020; Published online 21 July 2020. The Geotechnical Extreme Events Reconnaissance (GEER) association is supported by the National Science Foundation (NSF) through the Geotechnical Engineering Program under Grant Number CMMI‐1266418. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. The GEER association is made possible by the vision and support of the NSF Geotechnical Engineering Program Directors Richard Fragaszy and the late Cliff Astill. GEER members also donate their time, talent, and resources to collect time‐sensitive field observations of the effects of extreme events. Part of the research was sponsored by the NASA Earth Science Disasters Program (Grant Number 18‐DISASTER18‐0034) and performed in collaboration with the Jet Propulsion Laboratory and California Institute of Technology. Additional research support was provided by the Southern California Earthquake Center (SCEC), funded by the National Science Foundation (NSF) and U.S. Geological Survey (USGS), and by NSF RAPID Award Number EAR‐1945781. We would like to thank Camille Anderson, Steven Kourakos, Adam Bingham, Dipti Barari, Devin Katzenstein at Searles Valley Minerals and Jade Zimmerman at Naval Air Weapons Station China Lake for assisting with the preparation and deployment of reconnaissance activities at Searles Lake in November 2019. We also thank Kate Allstadt, Eric Thompson, Alex Grant, Katherine J. Kendrick, Mike Diggles, Shane T. Detweiler, Timothy Dawson (Guest Editor) at USGS and one anonymous reviewer, whose constructive comments helped improving this paper. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Data and Resources: Seismic moments and resulting moment magnitudes were taken from the Global Centroid‐Moment‐Tensor (GCMT) project (Ekström et al., 2012), available at (last accessed June 2020). We prefer these magnitudes because they are well constrained from data derived from global seismic networks. The use of GCMT magnitudes conforms with Next Generation Attenuation procedures as described by Contreras et al. (2020). Fault traces from the Uniform California Earthquake Rupture Forecast, version 3 (UCERF3) model were retrieved from the California Geological Survey (CGS) open data portal at (last accessed May 2020). The damage proxy map used was retrieved from the National Aeronautics and Space Administration (NASA) Advanced Rapid Imaging and Analysis (ARIA) Jet Propulsion Laboratory (JPL) event page at (last accessed January 2020). The USGS liquefaction hazard map produced following the MM 7.1 mainshock was retrieved from the USGS event page at (last accessed May 2020). The theoretical background of the USGS liquefaction hazard map used in this study is available at (last accessed May 2020). The HydroSHEDS database is available at (last accessed June 2020). The distance from the coast dataset from the NASA Ocean Color Group is available at (last accessed May 2020). Observation wells data were retrieved from the California Department of Water Resources (DWR) database at (last accessed May 2020). The USGS topographic map was retrieved from the USGS National Geospatial Program—US Topo at (last accessed May 2020). Elevation data were retrieved from Google Earth Pro (, last accessed May 2020). All maps were produced using QGIS (Open Source Geospatial Foundation Project, available at, last accessed January 2020). The unpublished manuscript by T. Dawson et al., “Field‐based observations of surface ruptures associated with the 2019 Ridgecrest earthquake sequence,” submitted to Bull. Seimol. Soc. Am. A summary table of observations at the Naval Air Weapons Station (NAWS), China Lake, 19 figures showing liquefaction features at the at the NAWS, China Lake and Argus, and three maps are available in the supplemental material to this article.
Group:Seismological Laboratory
Funding AgencyGrant Number
Southern California Earthquake Center (SCEC)UNSPECIFIED
Issue or Number:4
Record Number:CaltechAUTHORS:20200724-121439432
Persistent URL:
Official Citation:Paolo Zimmaro, Chukwuebuka C. Nweke, Janis L. Hernandez, Kenneth S. Hudson, Martin B. Hudson, Sean K. Ahdi, Matthew L. Boggs, Craig A. Davis, Christine A. Goulet, Scott J. Brandenberg, Kenneth W. Hudnut, Jonathan P. Stewart; Liquefaction and Related Ground Failure from July 2019 Ridgecrest Earthquake Sequence. Bulletin of the Seismological Society of America ; 110 (4): 1549–1566. doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104568
Deposited By: Tony Diaz
Deposited On:24 Jul 2020 20:04
Last Modified:06 Aug 2020 22:04

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