What is the Cascadia Subduction Zone and the 'Big One' earthquake?

The Cascadia Subduction Zone is an underwater fault line off the Pacific Northwest coast. The 'Big One' refers to a potential magnitude 9 earthquake that could emanate from this zone, causing widespread devastation.

Can scientists predict when the Cascadia earthquake will happen?

No, scientists cannot predict the exact timing of the Cascadia earthquake. While historical data suggests these large earthquakes occur on average every 500 years, they can cluster, making precise prediction impossible.

How does the earthquake early warning system work?

The early warning system uses thousands of seismic sensors to detect initial vibrations. Within 15 to 20 seconds, it can issue alerts via cell phones and sirens, giving people crucial time to take protective actions before the main shaking begins.

Home / Science / Cascadia's Big One: What We Know, What We Don't

Cascadia's Big One: What We Know, What We Don't

10 Feb

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Summary

The Cascadia Subduction Zone could trigger a magnitude 9 earthquake.
Predicting the exact timing of the Big One remains impossible.
An early warning system offers 15-20 seconds of crucial notice.

Cascadia's Big One: What We Know, What We Don't

The Pacific Northwest faces the looming threat of a major earthquake from the Cascadia Subduction Zone. Scientists have detailed potential consequences, including prolonged shaking lasting one to three minutes, significant infrastructure collapse, and widespread landslides.

Despite detailed knowledge of potential impacts, the precise timing of such an earthquake remains unpredictable. Historical evidence, including records of an 'orphan tsunami' in Japan from 1700 and geological data, indicates that large earthquakes occur in Cascadia roughly every 500 years on average, but these events can cluster.

Research into past earthquakes, preserved in coastal sediment cores, reveals that these seismic events can cause land to drop suddenly, exacerbating tsunami effects. Scientists also warn that the Cascadia earthquake could potentially trigger seismic activity along the San Andreas Fault in California.