Summary
A new study suggests that two major fault lines on North America's West Coast, Cascadia and San Andreas, could trigger earthquakes nearly at the same time. This could create a larger earthquake scenario than the often-discussed "Big One" earthquake. Researchers found that in the past 1,500 years, ruptures on these faults happened very close in time.
Key Facts
- The study says the Cascadia subduction zone and San Andreas fault could have linked seismic activity.
- Researchers analyzed deep-sea sediments to find earthquake patterns over 3,000 years.
- They found turbidites, which are sediment deposits created by underwater landslides, indicating closely timed earthquakes.
- In three historical cases, earthquakes on these faults occurred within minutes to hours of each other.
- A dual earthquake could impact cities like San Francisco, Portland, Seattle, and Vancouver simultaneously.
- The research suggests current disaster planning does not cover this potential dual-fault scenario.
- Further research is planned to gather additional evidence from San Andreas sites, like Lake Merced in San Francisco.
