Washington Prepares for Future Earthquakes After 2001 Nisqually Quake

SEATTLE, WA – October 20, 2025 — More than 20 years after the Nisqually earthquake shook Western Washington, state officials and scientists continue to improve earthquake preparedness and early warning systems.

The magnitude 6.8 earthquake, which struck on February 28, 2001, lasted about one minute and caused nearly $2 billion in damage. It was felt across the region, from Seattle to Olympia, and caused significant disruptions to offices, convention centers, and historic areas like Pioneer Square.

“The Nisqually earthquake in 2001 was actually the USA’s most damaging earthquake in the last 30 years,” said Harold Tobin, Director of the Pacific Northwest Seismic Network (PNSN).

Monitoring Systems Expanded

Since that event, the PNSN has grown its network to include more than 700 monitoring stations across Washington and Oregon. These include highly sensitive broadband seismometers that can detect earthquakes happening around the world. They can even measure tiny ground movements caused by the moon’s gravitational pull, known as earth tides.

Field technicians regularly inspect these sites. At Seward Park, near the Seattle Fault, a technician’s footsteps were picked up by sensors, showing how responsive the system has become.

Early Warning System in Place

Washington is now part of the ShakeAlert system, which can send earthquake alerts within 4 to 8 seconds after a quake is detected by multiple stations. These alerts go out through cell phone networks, similar to how Amber Alerts are sent, and can give people a few seconds to take cover or prepare before the shaking starts.

“The alerts are triggered when the ground motion is strong enough to notice — not necessarily damaging yet,” said Tobin.

Three Main Earthquake Threats

Experts say Washington is vulnerable to three main types of earthquakes:

1. Offshore megathrust quakes from the Cascadia Subduction Zone;

2. Shallow crustal quakes from faults like the Seattle Fault;

3. Deep earthquakes caused by the Juan de Fuca plate, like the Nisqually quake, which occur about every 20 to 30 years under Puget Sound.

What Residents Can Do

While early warning technology continues to improve, officials encourage the public to take steps to be ready:

• Secure heavy furniture and appliances;

• Have an emergency kit and communication plan;

• Know safe places in your home, school, or workplace;

• Practice earthquake drills regularly.

Preparedness at the individual and community level remains a key part of reducing damage and injuries when the next big quake hits.