New Wave Glider will study Earthquake Processes along U.S. Subduction Zones

The SV3 wave glider allows USGS scientists and collaborators to collect seafloor geodetic data, which relies on accurate measurements of the Earth’s geometric shape, gravity field, and orientation in space to continuously monitor seafloor movement. The principal scientific objectives are to constrain shallow strain accumulation between large earthquakes and to estimate the amount of strain released during and shortly after large subduction zone earthquakes. Equipped to collect global navigation satellite system and acoustic ranging (GNSS-A) seafloor geodetic data from some of Earths most critical remaining data gaps, the glider can travel faster between sites and operate in high current areas like Alaska, thanks to improved battery power.

“The use of an autonomous glider to collect data from the seafloor is a huge advancement over traditional methods, which involved driving an ocean-going vessel around a transponder and was prohibitively expensive. The advent of gliders is what allowed us to contemplate ‘getting in the game’ of seafloor geodesy,” said Research Geophysicist Janet Watt, who will use the glider in her research on the Cascadia Subduction Zone. “We are able to launch this wave glider directly from our ship, the Snavely, instead of needing to contract a vessel for each launch. This enables us to respond to local earthquakes in the Pacific Northwest by launching the wave glider rapidly (within days) to capture post-seismic movements on the seafloor.”

The glider was acquired through a collaboration between the Earthquake Hazards Program and the Coastal Marine Hazards and Resources Program. USGS scientists have recently joined academic colleagues in a pioneering effort to instrument the seafloor along the Cascadia and Alaskan subduction zones to understand plate motions and earthquake processes along shallow portions of these plate boundary faults, which have produced large earthquakes and tsunamis in the past.

The team has conducted repeat surveys of benchmarks after three recent Alaska subduction zone earthquakes, and made the first measurements of two new GNSS-A seafloor geodetic sites on either side of the plate boundary in southern Cascadia. This effort provides an example of advancements that can be achieved through successful cross-program planning and collaboration.

The first mission of the new SV3 glider will be along the southern Cascadia Subduction Zone margin, off the coast of northern California, in summer 2023.