The Pacific Northwest Seismic Network (PNSN), a member of the CNSS, is centered at the University of Washington's Dept. of Earth and Space Sciences . The PNSN is operated jointly by the University of Washington, the University of Oregon, and Oregon State University, and is funded by the U.S. Geological Survey, U.S. Department of Energy, and the State of Washington. PNSN data help scientists understand Pacific Northwest earthquake hazards, predict volcanic eruptions at Mount St. Helens, and determine the location of faults and volcanic magma chambers.

The scenic beauty of the Pacific Northwest landscape reflects active geologic processes. An offshore plate tectonic boundary, the Cascadia Subduction Zone, closely parallels the coastline of Washington and Oregon. Each year several thousand Pacific Northwest earthquakes are recorded, although only a few dozen earthquakes are large enough to be felt. Many are located near the urban areas of Seattle and Portland, where damaging earthquakes occur every 30 years or so. In addition, huge earthquakes occur directly on the Cascadia Subduction Zone margin every few hundred years, the last one in 1700.     Small daily earthquakes, plus occasional felt tremors, remind Pacific Northwest residents of earthquake hazards. As the populations of our major cities grow, more lives and property are at risk. The PNSN provides an educational outreach program on current seismicity and the potential damage from future earthquakes. PNSN data are combined with other geological and geophysical studies to assess Pacific Northwest earthquake hazards. The engineering and business communities, policy makers, and the public are using this information to develop strategies that could lessen damage and shorten post-earthquake recovery time. Better building codes, improved emergency plans, and safer bridges and buildings will reduce the impact of future earthquakes.     The PNSN collects and analyzes data to provide rapid and accurate information on earthquakes and volcanic activity in Washington and Oregon. Starting with five seismometers in 1969, the PNSN has grown to include over 150 seismograph stations. Data from the PNSN are used for research, daily monitoring, and to provide information to emergency managers and the public after felt events.

Installing a seismic sensor on Mt. Rainier, Washington. (Mt. Adams in background.)   Click here to expand figure and see caption

Monitoring Earthquakes and Volcanos The PNSN is installing a new generation of digital earthquake sensors in urban areas to accurately record ground motions from the lightest to the strongest shaking. Engineers use strong ground motion records from large earthquakes to improve construction techniques. While large earthquakes are rare, recording frequent small earthquakes with these improved instruments will help identify specific areas where shaking is likely to be amplified during damaging future earthquakes.

Earthquakes are recorded frequently on Mount St. Helens, Mount Rainier, and Mount Hood. After successfully using seismic activity to predict volcanic eruptions at Mount St. Helens, monitoring was expanded to other Cascade volcanos. The PNSN now monitors seismicity at all of the Cascade volcanos in Washington and Oregon.

Locations of seismic sensors in Washington and Oregon	The PNSN uses a network of seismic sensors to locate earthquakes in Washington and Oregon, and communicates earthquake information to a wide and diverse audience.

Rapid Information After Earthquakes
PNSN computers automatically determine earthquake locations and magnitudes and rapidly provide essential information. The Rapid Alert for Cascadia Earthquakes (RACE) system broadcasts earthquake location, magnitude, and shaking estimates within minutes to sites throughout the region via pagers attached to PC mapping packages. The earthquake alert information is also available immediately on the PNSN WEB pages: http://www.ess.washington.edu/SEIS/PNSN/

Advance Warning Before Tsunamis and Strong Shaking
A major earthquake on the Cascadia Subduction Zone will generate hazardous tsunami waves along the coast and strong shaking throughout western Washington and Oregon. The PNSN is developing the capability to detect the earliest earthquake signals arriving at the coast and immediately broadcast warnings to tsunami warning centers. The same coastal sensors could be used to send warnings to the inland cities of Seattle and Portland tens of seconds before the earthquake waves arrive. Operations at critical facilities like pipelines and railroads could be suspended before the start of strong shaking.

	The CNSSis an organization of institutions involved in seismic monitoring in the United States. The goal of the CNSS is to coordinate and standardize efforts to record and analyze seismic data in the U.S. Web site information: http://www.cnss.org/

	The U.S. Geological Survey is a sponsor of the CNSS

For more detailed information, visit the PNSN's WEB pages:

http://www.ess.washington.edu/SEIS/PNSN/

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