Global compilation of interferometric synthetic aperture radar earthquake source models: 1. Comparisons with seismic catalogs

Abstract

[1] While many earthquakes have now been studied using interferometric synthetic aperture radar (InSAR) data, a full assessment of the quality and additional value of InSAR source parameters compared to seismological techniques is still lacking. We compile a catalog of source models obtained using InSAR and estimate the corresponding centroid moment tensor (CMT) parameters; we refer to this compilation as the ICMT archive. We compare source parameters from over 70 InSAR studies of 57 global earthquakes with those in the Global CMT (GCMT), International Seismological Centre (ISC) and Engdahl-Hilst-Buland (EHB) seismic catalogs. We find an overall good agreement between fault strike, dip and rake values in the GCMT and ICMT archives. Likewise, the differences in seismic moment between these two archives are relatively small, and we do not find support for previously suggested trends of InSAR leading to larger moments than seismic data. However, epicentral locations show substantial discrepancies, which are larger for the GCMT (median differences of ∼21 km) than for the EHB and ISC catalogs (median differences of ∼10 km). Since InSAR data have a high spatial resolution, and thus should map epicentral locations accurately, this allows us to obtain a first independent estimate of epicentral location errors in the seismic catalogs. Earthquake depths from InSAR are systematically shallower than those in the EHB catalog, with a median of differences of ∼5 km. While this trend may be partly due to unmodeled crustal complexity, it is also compatible with the observation that the rupture of crustal earthquakes tends to propagate upward in the seismogenic layer.Citation: Weston, J., A. M. G. Ferreira, and G. J. Funning (2011), Global compilation of interferometric synthetic aperture radar earthquake source models: 1. Comparisons with seismic catalogs,

Deformation and Source Parameters of the 2015 Mw 6.5 Earthquake in Pishan, Western China, from Sentinel-1A and ALOS-2 Data

“…The predominant slip occurred at a depth of 9-14 km. That the InSAR centroid depth is shallower than the seismic depths is consistent with the median discrepancy of 5 km from previous studies [52]. The first plausible reason is variations in the properties of the local upper crust, as our results are derived from a homogeneous, elastic half-space model, which is the first-order approximation to the true crust.…”

SAR Data Analysis in Solid Earth Geophysics: From Science to Risk Management

“…As we have seen in section 3, the SAR-derived static co-seismic ground displacements are one of the most important datasets to constrain accurate models of the earthquake source [30]. The standard modeling techniques described previously can be implemented to operationally generate source models supporting event scenario development.…”

“…Globally, over three hundreds deformation fields related to the earthquake cycle (including inter-, co-, and post-seismic deformation), and over a thousand volcanic edifices, have been studied using SAR data since the beginning of the "InSAR era" [30] However, the space and ground segments of the first satellite SAR systems (i.e. ERS, ENVISAT, JERS, ALOS) were targeted mainly to scientific use and, while they could provide delayed data to carry out pre-or post-disaster scientific analyses eventually supporting the hazard assessment component [74], they lacked the near real time capabilities needed for use in the response phase.…”

“…In the co-seismic phase, the expected surface displacement, from tens of centimeters to several meters, and the nearly perfect elastic behavior due to the instantaneous deformation are perfect conditions to model the standard two-pass interferometry with the Okada solutions. [30][31] [32] showed that since the 1992 Landers earthquake, the onshore deformation for all the significant earthquakes worldwide (M > 5.5) have been imaged with the standard InSAR interferometry and most of them have been modeled with the Okada model. A common problem found in this approach is that, in general, coseismic interferograms contain a contribution from the post-seismic deformation that can affect some fault parameters [31].…”

Identifying Active Faults by Improving Earthquake Locations with InSAR Data and Bayesian Estimation: The 2004 Tabuk (Saudi Arabia) Earthquake Sequence

“…Interferometric Synthetic Aperture Radar (InSAR) has proven to be a useful tool to constrain the location, fault geometry, and slip of many strong (M w > 6) crustal earthquakes (e.g., Weston et al, 2011). InSAR can also be useful to locate smaller earthquakes if they are shallow enough to produce measurable deformation.…”