Washington Earthquakes

Washington is one of the most important earthquake regions in the United States because it is affected by the Cascadia Subduction Zone, deep earthquakes within the Juan de Fuca Plate, shallow faults beneath Puget Sound, and seismic activity around Cascade volcanoes.

Current Washington Earthquake Map

Track the latest available earthquake activity in Washington using USGS data. The interactive map shows M1.5+ earthquakes in Washington and updates when the page reloads or refreshes. Each colored circle represents an earthquake location. Click any circle to see detailed information including magnitude, location, time, and depth. Use the time filter buttons to view earthquakes from the last hour, 24 hours, 7 days, or 30 days.

About Washington Earthquakes

Washington has earthquake risk from several different sources. The offshore Cascadia Subduction Zone can produce earthquakes around M9, while faults beneath Puget Sound can create damaging shallow earthquakes close to major cities.

Washington also experiences deep earthquakes inside the subducting Juan de Fuca Plate and smaller earthquakes around Cascade volcanoes such as Mount Rainier, Mount St. Helens, Mount Baker, Glacier Peak, and Mount Adams.

This makes Washington different from California, where many damaging earthquakes are tied to major plate-boundary and crustal fault systems such as the San Andreas Fault. Washington’s earthquake picture is more layered: offshore subduction, deep plate earthquakes, shallow urban faults, and volcanic seismicity can all affect the state.

The Three Main Types of Washington Earthquakes

Washington’s earthquake risk is easier to understand when it is split into three main types: Cascadia megathrust earthquakes, deep intraslab earthquakes, and shallow crustal earthquakes.

These earthquake types are different in where they happen, how often they occur, and what kind of shaking or tsunami risk they can create.

Cascadia Megathrust Earthquakes

Cascadia megathrust earthquakes happen offshore, where the Juan de Fuca Plate is being pushed beneath the North American Plate. The Washington Geological Survey describes the Cascadia subduction zone as the largest active fault that will affect Washington and the wider Pacific Northwest.

The last full-margin Cascadia earthquake occurred in January 1700 and was about magnitude 9. Japanese historical records of an “orphan tsunami” helped scientists confirm the timing of that earthquake.

A future Cascadia earthquake would be especially dangerous for Washington’s outer coast because strong shaking and tsunami risk could happen close together.

A 2025 USGS Pacific Northwest hazard update estimates a 10–15% chance of an approximately magnitude 9 Cascadia earthquake in the next 50 years. That does not mean it will happen on a predictable schedule, but it does explain why Cascadia is such a major part of Washington earthquake planning.

Deep Intraslab Earthquakes

Deep intraslab earthquakes happen inside the subducting Juan de Fuca Plate as it bends and sinks beneath Washington. These earthquakes are usually much deeper than shallow fault earthquakes, often tens of kilometres below the surface.

Because they are deep, they can be felt across a wide area.

The 2001 Nisqually earthquake is the best-known recent example. The Pacific Northwest Seismic Network records the Nisqually earthquake as a magnitude 6.8 event within the subducting Juan de Fuca Plate near Olympia. It caused widespread damage across western Washington, including Olympia, Tacoma, and Seattle.

The same USGS Pacific Northwest hazard update estimates an 85% chance of an M6.5 or greater deep Puget Sound earthquake in the next 50 years, making this one of the most likely significant earthquake scenarios for western Washington.

Shallow Crustal Earthquakes

Shallow crustal earthquakes happen on faults within Washington’s upper crust. These can be especially damaging when they occur close to cities because the shaking begins near the surface and near buildings, roads, bridges, utilities, and people.

Important shallow fault zones include the Seattle Fault, Tacoma Fault, South Whidbey Island Fault, and other structures around Puget Sound.

Research on the A.D. 900–930 Seattle Fault earthquake links that event to uplifted shorelines around Puget Sound and strong local impacts.

USGS estimates a 17% chance of an M6.5 or greater crustal fault earthquake in the Puget Sound region within the next 50 years. That is lower than the deep earthquake probability, but a shallow earthquake near a city can still be extremely damaging.

Major Washington Seismic Hazards

Washington’s earthquake hazards are not limited to shaking. Depending on the source, an earthquake can also trigger landslides, liquefaction, ground cracking, infrastructure damage, and tsunamis.

• Cascadia Subduction Zone: Offshore fault capable of magnitude 9+ megaquakes and devastating tsunamis. Large Cascadia earthquakes have happened repeatedly over geologic time, but the timing is irregular.
• Seattle Fault: Shallow east-west fault zone beneath the Seattle area. A past major rupture around A.D. 900–930 produced shoreline uplift and local tsunami evidence around Puget Sound.
• South Whidbey Island Fault: Active fault zone in northern Puget Sound, capable of M7+ earthquakes
• Tacoma Fault: Runs through Tacoma and surrounding areas, part of the Seattle Fault Zone system
• Deep Intraslab Earthquakes: These earthquakes are another major hazard. They happen within the subducting Juan de Fuca Plate and include the 1949, 1965, and 2001 Puget Sound-area earthquakes.
• Mount St. Helens & Cascade Volcanoes: Frequent small earthquakes associated with volcanic activity

Seismically Active Areas in Washington

• The Puget Sound Basin including Seattle, Tacoma, Olympia, Everett, and surrounding communities, has the state’s highest population exposure to earthquake hazards.
• The Cascade Range also sees earthquake activity. Mount Rainier, Mount St. Helens, Mount Baker, Glacier Peak, and Mount Adams can produce small earthquakes linked to volcanic systems.
• The Olympic Peninsula and outer coast are close to the Cascadia Subduction Zone and face both earthquake and tsunami hazards.
• The Columbia Basin, Eastern Washington generally has lower earthquake activity than western Washington, but historical earthquakes show that damaging shaking is still possible.
• The Strait of Juan de Fuca and offshore Washington can also experience earthquakes related to the plate boundary, crustal structures, or the broader subduction system.

Cascade Volcanoes and Washington Earthquakes

Not every Washington earthquake is connected to Cascadia or Puget Sound faults. Some small earthquakes happen around Cascade volcanoes as rock, fluids, gases, or magma move underground.

The USGS Cascades Volcano Observatory monitors volcanoes across the Cascade Range, including Mount Rainier, Mount St. Helens, Mount Baker, Glacier Peak, and Mount Adams.

Earthquake activity around a volcano does not automatically mean an eruption is about to happen, but changes in earthquake patterns are one of the signs scientists watch closely.

Mount Rainier is especially important because of its location near populated areas and its history of lahars. Mount St. Helens is also closely monitored because it remains one of the most active volcanoes in the Cascade Range.

Not Every Washington Earthquake Is a Cascadia Earthquake

Because Cascadia gets so much attention, it is easy to assume every Washington earthquake is connected to the offshore subduction zone. That is not the case.

Many Washington earthquakes come from other sources, including shallow faults beneath Puget Sound, deep earthquakes within the subducting Juan de Fuca Plate, and volcanic earthquake activity around the Cascade Range. A small earthquake near Mount St. Helens, for example, is a very different event from a deep earthquake near Olympia or a large offshore Cascadia earthquake.

This is why location and depth matter. A deep earthquake may be felt across a wide area, while a shallow earthquake near a city can cause stronger local shaking. An offshore Cascadia earthquake brings a different concern again: long-duration shaking and tsunami risk for the Washington coast.

The main takeaway is simple: Washington has several earthquake systems working at the same time. Cascadia is the largest hazard, but it is not the only one.

Historical Washington Earthquakes

Washington has experienced several major earthquakes, including deep Puget Sound events, older crustal fault earthquakes, and the 1700 Cascadia earthquake.

• 1700 Cascadia (M9.0): Struck on January 26, 1700 and was the last known full-margin Cascadia rupture. It was about magnitude 9 and generated a Pacific-wide tsunami that was recorded in Japanese historical documents.
• 1872 North Cascades (M6.8-7.4): On December 14, 1872, Washington experienced one of the largest earthquakes in its recorded history. But because it happened before modern instruments, the exact magnitude and source remain uncertain. It was felt from British Columbia to Oregon.
• 1949 Olympia (M6.8): On April 13, 1949, a deep intraslab earthquake struck between Olympia and Tacoma at about 50 km depth. (Note: older catalogs assigned surface wave magnitudes of 6.8–7.1; the current USGS moment magnitude is 6.7. It caused significant damage in in Olympia, Tacoma, Seattle, and nearby communities.
• 1965 Seattle-Tacoma (M6.7): Deep earthquake south of Seattle On April 29, 1965, that caused damage across western Washington.
• 2001 Nisqually (M6.8): A deep intraslab earthquake on February 28, 2001 near Olympia that caused hundreds of injuries and more than $2 billion in damage across western Washington, according to the Pacific Northwest Seismic Network.

Washington Earthquakes and Tsunami Risk

Earthquake safety in Washington also means tsunami safety, especially along the outer coast.

A large Cascadia earthquake could create strong shaking and tsunami waves close together. Official Washington Emergency Management guidance explains that people on parts of the outer coast may have only 10 to 15 minutes once the ground stops shaking to reach high ground before a tsunami arrives.

If you are near the coast and feel strong or long shaking, move inland or to higher ground after the shaking stops. Do not wait for a siren if the natural warning signs are clear.

How Washington Earthquakes Are Monitored

Washington earthquake activity is monitored by the Pacific Northwest Seismic Network, the USGS Earthquake Hazards Program, the Washington Geological Survey, and Washington Emergency Management.

These organizations track earthquakes, faults, volcanic activity, tsunami hazards, and earthquake preparedness information.

Earthquake Preparedness in Washington

Washington is part of the ShakeAlert earthquake early warning system, which can provide seconds of warning before strong shaking reaches some locations.

That warning time will not stop an earthquake, but it may give people time to drop, cover, and hold on.

During shaking, Drop, Cover, and Hold On. If you are on the coast and feel strong or long shaking, move to high ground after the shaking stops.

Keep emergency supplies, including water, food, medications, lights, batteries, and basic first-aid items. Secure heavy furniture, bookcases, televisions, and water heaters.

Know whether your home, school, or workplace is in a tsunami evacuation zone. Have an out-of-area emergency contact in case local phone networks are overloaded.

You can also take part in the annual Great Washington ShakeOut drill.

🗺️ Related Maps

List of global earthquakes over the last 24 hours

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More resources: WA DNR Earthquake Information | WA Emergency Management | Pacific Northwest Seismic Network