Cascadia subduction zone is overdue for a major earthquake. A key question regarding natural hazards is whether such an earthquake can generate a large tsunami. Our ability to answer this question is limited by the lack of deformation measurements near the shallow portion of the subduction zone.
Recently, my group started to collaborate with physical oceanographers at GSO (Randy Watts and Kathleen Donohue) to investigate this problem. Funded by the National Science Foundation (award 1728060), we deployed four Current and Pressure Recording Inverted Echo Sounder (C-PIES) offshore Oregon in April 2017 to quantify the water-column contributions using in situ observations (Figure 1). C-PIES (Figure 2) are unique because they simultaneously measure bottom pressure, current, and round-trip acoustic travel time from the sea floor to surface and back. By combining these measurements, the water signal can be separated from the measured bottom pressure signal. We will recover these instruments in November 2017.