Pacific Northwest Seismic Network

Pacific Northwest Seismic Network
Name	Pacific Northwest Seismic Network
Founded	1969
Headquarters	University of Washington
Key people	John Vidale
Focus	Seismology, Volcanology, Earthquake early warning
Parent	University of Washington, University of Oregon
Website	pnsn.org

Pacific Northwest Seismic Network. It is a comprehensive seismic and volcanic monitoring system for the U.S. states of Washington and Oregon. Operated jointly by the University of Washington and the University of Oregon, the network detects and studies earthquakes, volcanic activity, and crustal deformation across the Cascadia subduction zone and the broader Pacific Northwest region. Its data is critical for scientific research, public safety, and the operation of the ShakeAlert earthquake early warning system.

Overview

The primary mission is to monitor the complex and active tectonic environment of the Pacific Northwest, which is shaped by the convergence of the Juan de Fuca Plate and the North American Plate. This tectonic setting generates significant seismic hazards, including the potential for very large megathrust earthquakes on the Cascadia subduction zone, deep intraplate earthquakes within the Juan de Fuca Plate like the 2001 Nisqually earthquake, and shallow crustal quakes on faults such as the Seattle Fault. The network also monitors the Cascade Volcanic Arc, which includes active volcanoes like Mount St. Helens, Mount Rainier, and Mount Hood. Real-time data from hundreds of stations supports fundamental research in seismology and informs critical hazard assessments by agencies like the United States Geological Survey and Washington State Department of Natural Resources.

History and Development

The origins trace back to the 1960s, following the devastating 1964 Good Friday earthquake in Alaska, which heightened awareness of Pacific Northwest seismic risks. It was formally established in 1969 through collaboration between the University of Washington and the University of Oregon. Early instrumentation was significantly expanded after the 1980 eruption of Mount St. Helens, which underscored the need for integrated volcanic monitoring. Major advancements occurred in the 1990s and 2000s with the deployment of modern broadband seismometer networks and Global Positioning System stations to study crustal deformation. The network has been integral to defining the seismic threat of the Cascadia subduction zone, following pioneering work by researchers like Brian Atwater on paleoseismology.

Monitoring and Detection Capabilities

The system operates a dense array of over 500 seismic stations, including strong-motion seismometers, broadband seismometers, and instruments specifically deployed on volcanoes. This infrastructure is complemented by a network of Global Positioning System receivers and tiltmeters to measure ground deformation. Data is telemetered in real-time to processing centers at the University of Washington and the University of Oregon. The network automatically detects and locates thousands of earthquakes annually, from tiny tremors to major events, and provides rapid notification to the United States Geological Survey National Earthquake Information Center. This real-time data flow is the backbone for the ShakeAlert earthquake early warning system being implemented along the West Coast of the United States.

Significant Contributions and Research

Scientists have produced landmark studies on the Cascadia subduction zone, documenting its rupture history and potential for a megathrust earthquake exceeding M 9.0. Research has illuminated the nature of episodic tremor and slip, a slow seismic phenomenon discovered in the region. The network provided crucial data for analyzing major events like the 2001 Nisqually earthquake and the 2004 Parkfield earthquake. Volcanological research includes detailed studies of the 2004-2008 eruption of Mount St. Helens and ongoing monitoring of Mount Rainier. Its catalog is essential for developing regional seismic hazard maps used in building codes and by emergency managers.

Organizational Structure and Partnerships

The network is a cooperative venture, with the University of Washington's Department of Earth and Space Sciences operating the northern section and the University of Oregon's Department of Earth Sciences managing the southern section. It works under cooperative agreements with the United States Geological Survey Earthquake Hazards Program and the United States Geological Survey Volcano Hazards Program. Key funding partners include the Federal Emergency Management Agency and the National Science Foundation. The network collaborates closely with state geological surveys like the Washington State Department of Natural Resources and emergency management agencies such as the Washington Military Department.

Public Outreach and Hazard Mitigation

A major function is to translate complex seismic data into actionable public information through its website, public lectures, and engagement with media outlets following significant events. The network works directly with state and local emergency managers, including the Washington Emergency Management Division, to support earthquake preparedness and response planning. Data and analysis directly feed into the ShakeAlert system, which provides crucial seconds to minutes of warning for protective actions. Educational resources are provided to K–12 schools, and public scientists regularly contribute to community preparedness events and drills throughout Oregon and Washington.

Category:Seismological organizations Category:University of Washington Category:University of Oregon Category:Earthquake warning systems Category:Volcanology organizations