Modeling Surface Mass Load Displacements Along The Cascadia Subduction Zone

The Earth’s surface is under constant strain from different mass loads. Surface mass loads, such as the oceans, atmosphere, and continental water reservoirs, exert forces on the elastic solid Earth, inducing crustal deformation. These loads move over Earth\u27s surface on time scales varying from less than a day to many thousand years. Since the Earth is elastic and not perfectly rigid, the pressure from these loads deforms the shape of Earth’s surface. Horizontal and vertical displacement responses due to a load can be recorded using Global Positioning System (GPS) receivers. Modeling and removing surface-mass loading signals, which are present in all GPS time series, can reduce the variance in the time series. Surface deformation is of particular interest along subduction zones. A subduction zone is an area of tectonic plate collision where the more dense plate subducts, or moves underneath, the less dense plate. The Cascadia Subduction Zone extends from Vancouver Island down to Northern California. This research project focuses on using the python-based software program LOADDEF to accurately compute displacement responses of the Earth to oceanic, atmospheric, and hydrologic loads. These modeled responses are then compared to the observed displacement responses measured by the Plate Boundary Observatory along the Cascadia Subduction Zone