VERTICAL DEFORMATION FIELD FOR THE CASCADIA REGION DERIVED FROM INSAR, LEVELING AND TIDAL RECORDS

Leveling and tidal gauge data in the Cascadia subduction zone have shown that the vertical deformation varies in both the normal- and along- strike directions. However, due to the sparseness of the measurements, large gap zones appear in many areas where there are no inhabitants, impeding our understanding of the interseismic locking pattern on the subduction interface.The launches of European Space Agency’s (ESA’s) Sentinel-1A and Sentinel-1B in 2014 and 2016 started a new era of operational Interferometric Synthetic Aperture Radar (InSAR) observations with down to 6-day repeating time. The large data coverage and ESA’s open-data policy make Sentinel-1A/B an important data source to study large scale vertical deformation in a continental scale. Thanks to the well-controlled orbit, the geometry decorrelation due to large spatial baseline has been largely reduced, the small-baseline interferometric configuration can be applied to reduce the temporal decorrelation due to the dense vegetation in this region.The leveling and tidal gauge data will help to model and to eliminate the atmospheric phase delay for large-scale InSAR analysis.After combining the point-wise measurements and high-resolution geodetic images, we will present the vertical displacement field along the Cascadia coastal region. Our results will improve the model resolution for better understanding of the potential seismic hazard in this region. We will also investigate some local subsidence along coastal towns due to anthropogenic factors.