RAPID: Sentinel-1 and ALOS-2 InSAR interferograms to support community modeling, mapping, and estimation of hazards from strike-slip and thrust fault interactions in Haiti.

This RAPID project supports the analysis of satellite data following the August 14, 2021, Haiti earthquake (M=7.2) by combining Sentinel-1 and ALOS-2 InSAR observations. The analysis will allow preliminary interpretation of the interaction of strike-slip and thrust faults that rupture during the Haiti earthquake sequence. Systematic release of preliminary and refined images as each new satellite pass occurs (~5-7 days) and as the aftershock sequence and supporting field work takes place.

InSAR, along with aftershock relocations, will be critical to help define the fault geometry necessary for understanding the rupture and subsequent stress changes on adjacent faults. Updated images will be released right after each acquisition (https://topex.ucsd.edu/haiti_7.2/). Early distribution of these data to local field scientists informs geologic mapping that will contribute to collecting ephemeral data on surface slip.

Higher accuracy InSAR observations produced using the GMTSAR package, with stacking and noise reduction, combining data from Sentinel-1 and ALOS-2, are critical for future modeling efforts. The method increases the accuracy of InSAR line-of-sight (LoS) deformation maps while providing data products to help researchers identify ancillary fault structures with co- and post-seismic slip that will be constrained at large scale by available GPS data.

The InSAR imagery can help resolve how significant the component of dip slip on the eastern segment of the Enriquillo Plantain Gardens Fault is and how its interaction with thrust faults is a major factor controlling this fault segmentation and thus impacts the seismic hazard in this trans-pressive boundary of the Caribbean plate. This project will support a female graduate student who will process the images weekly.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.