Co‐ and Early Postseismic Deformation Due to the 2019 Ridgecrest Earthquake...

Wang, K., and R. Burgmann (2020), Co‐ and Early Postseismic Deformation Due to the 2019 Ridgecrest Earthquake Sequence Constrained by Sentinel‐1 and COSMO‐SkyMed SAR Data, Seismological Research Letters, 91, 1998-2009, doi:10.1785/0220190299.

The 2019 Ridgecrest earthquake sequence ruptured a series of conjugate faults in the

broad eastern California shear zone, north of the Mojave Desert in southern California.

The average spacing between Global Navigation Satellite System (GNSS) stations around

the earthquakes is 20–30 km, insufficient to constrain the rupture details of the earthquakes.

Here, we use Sentinel-1 and COSMO-SkyMed (CSK) Synthetic Aperture Radar

data to derive the high-resolution coseismic and early postseismic surface deformation

related to the Ridgecrest earthquake sequence. Line of sight (LoS) Interferometric

Synthetic Aperture Radar displacements derived from both Sentinel-1 and CSK data are

in good agreement with GNSS measurements. The maximum coseismic displacement

occurs near the Mw 7.1 epicenter, with an estimated fault offset of ∼4:5 m on a northwest-

striking rupture. Pixel tracking analysis of CSK data also reveals a sharp surface offset

of ∼1 m on a second northwest-striking fault strand on which the Mw 6.4 foreshock

likely nucleated, which is located ∼2–3 km east of the major rupture. The lack of clear

surface displacement across this fault segment during theMw 6.4 event suggests this fault

might have ruptured twice, with more pronounced and shallow slip during the Mw 7.1

mainshock. Both Sentinel-1 and CSK data reveal clear postseismic deformation following

the 2019 Ridgecrest earthquake sequence. Cumulative postseismic deformation near the

Mw 7.1 epicenter ∼2 months after the mainshock reaches ∼5 cm along the satellites’

LoSs. The observed postseismic deformation near the fault is indicative of both afterslip

and poroelastic rebound. We provide data derived in this study in various data formats,

which will be useful for the broad community studying this earthquake sequence.

PDF of Publication: 
Download from publisher's website.
Research Program: 
Earth Surface & Interior Program (ESI)