The Cascadia Offshore Subduction Zone Observatory Infrastructure Project: A Year 2 Update
Description:
The Cascadia Offshore Subduction Zone Observatory (COSZO) is an NSF-funded mid-scale infrastructure project that is on track to add new seismic and geodetic capabilities in 2026 to the Ocean Observatories Initiative (OOI) Regional Cabled Array (RCA) off Newport, Oregon. Geophysical observations show that the Cascadia megathrust is mostly locked from the coastline to the deformation front, but off central Oregon they are consistent with a narrowly locked megathrust near the deformation front that transitions to creeping behavior beneath the shelf where there are two clusters of earthquakes on the megathrust, including repeating and very low frequency earthquakes. COSZO is constructing updated science junction boxes to be added to three primary nodes on the continental slope and shelf that currently do not support seafloor geophysical observations. We are procuring a newly developed ocean bottom seismic package, which houses a broadband seismometer and strong motion accelerometer and connects directly to a low-frequency hydrophone and a differential pressure gauge, for each new junction box and an additional site on the shelf with an existing science junction box. Two types of calibrated pressure gauges are under construction and we will also procure absolute pressure gauges and current meters. Together with sensors already on the OOI RCA at the Slope Base and Hydrate Ridge sites, the infrastructure will form a “critical mass” offshore geophysical observatory to study fault coupling and deformation of the Cascadia megathrust and the overlying accretionary prism and support efforts to prototype offshore earthquake and tsunami early warning. In Fall 2024, our Science Advisory Committee held its first meeting. One recommendation is to improve the awareness and usability of existing OOI RCA geophysical data at the Slope Base and Hydrate Ridge sites. To this end, we will duplicate existing seafloor pressure data from the OOI database into Earthscope Data Services (formerly the IRIS DMC) and evaluate whether any unused contingency funds can be prioritized to enhance the geophysical instrumentation at these sites.
Session: ESC-SSA Joint Session:Seismology in the Global Oceans: Advances in Methods and Observations - I
Type: Oral
Date: 4/15/2025
Presentation Time: 04:30 PM (local time)
Presenting Author: Mika
Student Presenter: No
Invited Presentation:
Poster Number:
Authors
Mika Thompson Presenting Author Corresponding Author usherm42@uw.edu University of Washington |
William Wilcock wilcock@uw.edu University of Washington |
Michael Harrington mikeh77@uw.edu University of Washington |
David Schmidt dasc@uw.edu University of Washington |
Deborah Kelley dskelley@uw.edu University of Washington |
Harold Tobin htobin@uw.edu University of Washington |
Marine Denolle mdenolle@uw.edu University of Washington |
Matthew Khoo mattkhoo@uw.edu University of Washington |
Geoffrey Cram cramg@uw.edu University of Washington |
Amanda L Labrado all91@uw.edu University of Washington, Seattle, Washington, United States |
Dana A Manalang manalang@uw.edu University of Washington, Seattle, Washington, United States |
Chuck McGuire mcguire@apl.washington.edu University of Washington, Seattle, Washington, United States |
James W Tilley jtilley@uw.edu University of Washington, Seattle, Washington, United States |
Mark A Zumberge mzumberge@ucsd.edu University of California, San Diego, La Jolla, California, United States |
Glenn S Sasagawa gsasagawa@ucsd.edu University of California, San Diego, La Jolla, California, United States |
The Cascadia Offshore Subduction Zone Observatory Infrastructure Project: A Year 2 Update
Category
ESC-SSA Joint Session:Seismology in the Global Oceans: Advances in Methods and Observations