Fleet of rapid response ocean bottom seismographs deployed after M7.0 earthquake in Northern California
A fleet of rapid response ocean bottom seismographs was deployed to monitor aftershocks and gather critical data on seismic activity following the M7.0 earthquake that struck offshore Northern California on December 5, 2024.
Wayne Baldwin (USGS), Eric Moore (USGS), and Hannah Brewer (Woods Hole Oceanographic Institution) preparing the rapid response ocean bottom seismograph fleet for deployment. Image credit: Nathan Miller, USGS Woods Hole Coastal and Marine Science Center
A fleet of rapid response ocean bottom seismographs was deployed within 11 days after an M7.0 earthquake struck offshore Northern California and the Pacific Northwest on December 5, 2024.
To enhance monitoring efforts, 9 ocean bottom seismographs were placed along the seafloor near the rupture zone, complementing an existing network of 115 seismic nodes and 18 real-time aftershock monitoring stations deployed on land by the USGS Earthquake Hazards Program.
The deployment, led by the Woods Hole Oceanographic Institution (WHOI) and the United States Geological Survey (USGS), is the fastest in the program’s history and aims to collect high-value seismic data for hazard assessment and improved earthquake preparedness.
“These instruments will enable us to better understand the earthquake’s impact, assess the risk of further damage, and improve future preparedness,” the USGS and WHOI team stated.
The seismographs will remain on the seafloor for 45 days before retrieval. Scientists will then analyze the data to improve understanding of offshore seismic activity and fault characteristics in the region.
The collected information will be integrated with land-based seismic data to produce a more comprehensive picture of how the fault system behaves after a major rupture.
Scientists emphasize that the ability to quickly deploy the instruments allows them to capture important early aftershock sequences and refine earthquake models, ultimately contributing to improved safety measures for coastal communities.
The USGS and WHOI team will return in February 2025 to recover the instruments and begin analyzing the collected data. Findings from this deployment are expected to enhance seismic hazard assessments and provide valuable data into the behavior of offshore earthquakes.
The earthquake, which had its epicenter approximately 70 km (43 miles) offshore near Cape Mendocino, generated strong shaking and was followed by multiple aftershocks.
The rapid-response OBS fleet consists of smaller and highly portable instruments that can be quickly transported and deployed. Once on the seafloor, these seismographs will continuously monitor aftershocks and record seismic waves that provide data into fault zone behavior and the velocity structure of the region. The information is crucial for refining earthquake hazard models and improving early warning systems.
Having a dedicated fleet of rapid response ocean bottom seismographs marks a major advancement in earthquake science and hazard mitigation.
The ocean bottom seismograph (OBS) network is designed for rapid deployment following major seismic events. Unlike traditional ocean bottom instruments which require over 100 days for deployment because of their size and logistical challenges, the rapid response fleet reduces this timeline and ensures that important seismic data is recorded when it is most valuable.
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The December 5 earthquake occurred in a seismically active region where the Pacific, North American, and Gorda plates interact along the Mendocino Triple Junction.
The area has experienced numerous earthquakes in the past which makes it a key location for seismic research. Understanding how stress propagates through the fault system is essential for assessing long-term seismic risk along the U.S. West Coast.
References:
1 Seafloor Seismographs Rapidly Deployed Following Major Earthquake Offshore Northern California – USGS – January 27, 2025
I'm a dedicated researcher, journalist, and editor at The Watchers. With over 20 years of experience in the media industry, I specialize in hard science news, focusing on extreme weather, seismic and volcanic activity, space weather, and astronomy, including near-Earth objects and planetary defense strategies. You can reach me at teo /at/ watchers.news.
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