The new ocean-bottom seismographs record shaking with an accelerometer. Similar to the computer chips that measure motion in smartphones, this finger-nail-sized sensor can measure shaking in any orientation, removing the need for the large, complex, and power-consuming leveling systems used by traditional seafloor instruments. Combining the accelerometer with low-power recording electronics means the new instruments need less battery power, further reducing the size and weight of the instruments.
The fleet currently has 10 instruments that measure 24 by 24 inches and weigh about 50 pounds. The instruments can be deployed for about 50 days in water up to ~4 miles deep. By having a fleet of instruments designed for rapid response, we can record events during periods of exceptionally high scientific value, for a fraction of the cost of long-term deployments.
The new instruments were successfully tested offshore in Cape Cod, Massachusetts in April 2024. A response plan for providing on-call staff and equipment for rapid deployments offshore California, the Pacific Northwest, Alaska, and the Caribbean is being developed by the USGS and Woods Hole Oceanographic Institution. The goal is to be able to mobilize and deploy the fleet within 2 weeks of marine seismic events.
The new fleet represents a significant advancement in rapid response capabilities for marine geohazards research. This next-generation fleet can provide high-value data to the scientific community and help enhance our understanding of seismic and other geohazards.