Exploring the absolute pressure gauge data from the Cascadia Initiative OBS deployment for transient changes in seafloor elevation

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Part 1The proposed work will study the use of pressure gauges for geodetic observations to monitor vertical deformation in the offshore regions of the Cascadia subduction zone. The work could contribute to our understanding of slow-slip seismic events and their potential for the generation of large tsunamis. The project will use the Cascadia Initiative?s absolute pressure gauges (APG) data set to develop methods for removing oceanographic noise from the observations to determine what types and time scales can be detected using pressure gauges. Additionally, the project will search for possible vertical deformation that may have occurred during the Cascadia Initiative deployment. The APG records have the potential to detect slow slip events in the accretionary prism, which could change or enhance the understanding of the displacement behavior of these faults and of deformation in the overlying accretionary prism. The results could be applicable to the future data acquired in Cascadia region and elsewhere.Part 2Funds are provided to study the large Cascadia Initiative (CI) absolute pressure gauge (APG) data set that will allow the use of pressure gauges for geodetic observations to monitor deformation in the offshore regions of the Cascadia subduction zone. The utility of APG data for geodetic observations is limited by high noise levels from oceanographic signals and by the inherent drift in the sensors. The proposed research will use this large data set first to develop methods of removing oceanographic noise from these observations so as to determine what types and time scales of vertical deformation can be detected using pressure gauges. The second component of the research will be to search for possible vertical deformation that may have occurred during the CI deployment. The discovery of seismic slow slip events or similar events beneath the seafloor will likely change or enhance our understanding of the displacement behavior of these faults and of deformation in the overlying accretionary prism. This results will be applicable not only to the data acquired in Cascadia, but also to observations from future ocean bottom seismometer deployments with that are equipped with APGs, which also includes a GeoPRISMS focus site, the Hikurangi (New Zealand) subduction margin.