Co‐ and Early Postseismic Deformation Due to the 2019 Ridgecrest Earthquake Sequence Constrained by Sentinel‐1 and COSMO‐SkyMed SAR Data

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.