FAQ for Journalists: Earthquakes and Related Hazards in Cascadia

Where is Cascadia?

The Cascadia region stretches from Brooks Peninsula on Vancouver Island, British Columbia in the north to Cape Mendocino, California in the south. Our member states and provinces are British Columbia, California, Oregon and Washington. 

Why is it the ‘Cascadia’ Region Earthquake Workgroup?

The impact of earthquakes and related hazards in this region transcend geographic and political borders. Similarly, CREW strives to unite public and private representatives from all three states and British Columbia in efforts to reduce damage from these inevitable events.

What is an earthquake?

An earthquake is caused by a sudden slip on a fault, which is a thin zone of weakness between two larger blocks of rock. As stress builds on a fault (usually due to the relative motions between tectonic plates), the fault will remain stuck or motionless until the stress level exceeds the strength of the fault. Stresses may build for hundreds or thousands of years. Once the stress level exceeds the strength of the fault, the fault slips suddenly and releases energy in waves that travel through the rock to cause the shaking that we feel during an earthquake.

What are earthquake-related hazards?

An earthquake often triggers events we call hazards, including ground shaking, landslides, liquefaction (when soil liquefies during shaking) and tsunamis.

Who is at risk?

Cascadia has a history of seismic activity. The extent of your risk depends on where you live in this region, but all residents should be prepared for a damaging quake in their lifetimes.

What should I do when I feel ground shaking?

Drop, cover and hold. If you are inside when you feel the ground shake, drop down to the floor. Take cover under a sturdy piece of furniture or seek cover against an interior wall and protect your head and neck with your arms. Avoid danger spots near windows, hanging objects, mirrors, or tall furniture. Hold the position until the ground stops shaking and it is safe to move. If you are outside, get into the open, away from buildings, power lines and trees. Be alert for falling rock and other debris that could be loosened by the earthquake. If you are on or near the coast, move far inland to higher ground after ground shaking stops.

What are tsunami and why do they matter to Cascadia? 

Most earthquakes in the Cascadia region will not result in tsunamis because they do not uplift the seafloor. However, a Cascadia subduction zone earthquake would generate a tsunami, which is actually a series of waves (not a ‘tidal wave’). In some cases, waves may be up to 33 feet (10 meters) high, flooding everything in their path. Tsunamis can injure or kill many people and cause significant damage to buildings and other structures. People can escape tsunamis by moving to higher ground and far inland after ground shaking stops.

Who responds during and after and earthquake?

Who can I talk to about Cascadia earthquakes and related hazards?

Please see our list of CREW media contacts.

Where can I learn more?