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The Normal-Faulting 2020 M_w 5.8 Lone Pine, Eastern California, Earthquake Sequence

Hauksson, Egill and Olson, Brian and Grant, Alex and Andrews, Jennifer R. and Chung, Angela I. and Hough, Susan E. and Kanamori, Hiroo and McBride, Sara K. and Michael, Andrew J. and Page, Morgan and Ross, Zachary E. and Smith, Deborah E. and Valkaniotis, Sotiris (2021) The Normal-Faulting 2020 M_w 5.8 Lone Pine, Eastern California, Earthquake Sequence. Seismological Research Letters, 92 (2A). pp. 679-698. ISSN 0895-0695. doi:10.1785/0220200324.

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The 2020 M_w 5.8 Lone Pine earthquake, the largest earthquake on the Owens Valley fault zone, eastern California, since the nineteenth century, ruptured an extensional stepover in that fault. Owens Valley separates two normal‐faulting regimes, the western margin of the Great basin and the eastern margin of the Sierra Nevada, forming a complex seismotectonic zone, and a possible nascent plate boundary. Foreshocks began on 22 June 2020; the largest M_w 4.7 foreshock occurred at ∼6km depth, with primarily normal faulting, followed ∼40hr later on 24 June 2020 by an Mw 5.8 mainshock at ∼7km depth. The sequence caused overlapping ruptures across a ∼0.25km² area, extended to ∼4km²⁠, and culminated in an ∼25km² aftershock area. The mainshock was predominantly normal faulting, with a strike of 330° (north‐northwest), dipping 60°–65° to the east‐northeast. Comparison of background seismicity and 2020 Ridgecrest aftershock rates showed that this earthquake was not an aftershock of the Ridgecrest mainshock. The M_w–m_B relationship and distribution of ground motions suggest typical rupture speeds. The aftershocks form a north‐northwest‐trending, north‐northeast‐dipping, 5 km long distribution, consistent with the rupture length estimated from analysis of regional waveform data. No surface rupture was reported along the 1872 scarps from the 2020 M_w 5.8 mainshock, although, the dipping rupture zone of the M_w 5.8 mainshock projects to the surface in the general area. The mainshock seismic energy triggered rockfalls at high elevations (⁠>3.0km⁠) in the Sierra Nevada, at distances of 8–20 km, and liquefaction along the western edge of Owens Lake. Because there were ∼30% fewer aftershocks than for an average southern California sequence, the aftershock forecast probabilities were lower than expected. ShakeAlert, the earthquake early warning system, provided first warning within 9.9 s, as well as subsequent updates.

Item Type:Article
Related URLs:
URLURL TypeDescription
Hauksson, Egill0000-0002-6834-5051
Olson, Brian0000-0001-8548-4101
Grant, Alex0000-0002-5096-4305
Andrews, Jennifer R.0000-0002-5679-5565
Chung, Angela I.0000-0002-3767-6018
Hough, Susan E.0000-0002-5980-2986
Kanamori, Hiroo0000-0001-8219-9428
McBride, Sara K.0000-0002-8062-6542
Michael, Andrew J.0000-0002-2403-5019
Page, Morgan0000-0001-9321-2990
Ross, Zachary E.0000-0002-6343-8400
Smith, Deborah E.0000-0002-8317-7762
Valkaniotis, Sotiris0000-0003-0003-2902
Alternate Title:The Normal-Faulting 2020 Mw 5.8 Lone Pine, Eastern California, Earthquake Sequence
Additional Information:© 2020 Seismological Society of America. Manuscript received 14 September 2020. Published online 16 December 2020. The authors thank L. Jones and J. McGuire, for assistance and discussions, as well as anonymous SRL and U.S. Geological Survey (USGS) reviewers. This research was supported by USGS/National Earthquake Hazards Reduction Program (NEHRP) Grant G19AP00035 and the Gordon and Betty Moore Foundation Grant Number 5229 to California Institute of Technology (Caltech). The authors used Generic Mapping Tools (GMT) from Wessel et al. (2013) to make the figures. The Southern California Seismic Network (SCSN) is partially funded by USGS Cooperative Agreements G19AC00296, G20AP00037, and CalOES Agreement 6012‐2017 with Caltech. The authors appreciate the support provided by more than 20 SCSN and Southern California Earthquake Data Center (SCEDC) staff members who maintain stations and communications systems, as well as data flow, processing, and archiving. Sentinel 1 and Sentinel 2 images were provided through the European Space Agency (ESA)‐Copernicus program. Interferometric Synthetic Aperture Radar (InSAR) results were generated with the processing services of Geohazards Exploitation Platform (GEP,, last accessed November 2020) in the context of the Committee on Earth Observation Satellites (CEOS) Seismic Hazards Demonstrator initiative. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Group:Seismological Laboratory
Funding AgencyGrant Number
Gordon and Betty Moore Foundation5229
California Office of Emergency Services6012‐2017
Issue or Number:2A
Record Number:CaltechAUTHORS:20201218-095600904
Persistent URL:
Official Citation:Egill Hauksson, Brian Olson, Alex Grant, Jennifer R. Andrews, Angela I. Chung, Susan E. Hough, Hiroo Kanamori, Sara K. McBride, Andrew J. Michael, Morgan Page, Zachary E. Ross, Deborah E. Smith, Sotiris Valkaniotis; The Normal‐Faulting 2020 Mw 5.8 Lone Pine, Eastern California, Earthquake Sequence. Seismological Research Letters 2020; 92 (2A): 679–698. doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107190
Deposited By: George Porter
Deposited On:18 Dec 2020 20:11
Last Modified:16 Nov 2021 19:00

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