California is experiencing a notable uptick in seismic activity in 2024. The recent 7.1-magnitude earthquake, along with the 3.9-magnitude quake in Ontario, is part of a broader pattern that has made this year one of the most active earthquakes in the region since 1988. Currently, 14 earthquakes measuring 4.0 or higher have been recorded in Southern California, near the typical range for an entire year (between 15 and 20). This surge in earthquakes this year suggests an increased frequency compared to normal. Does this mean Washington should anticipate more earthquake activity?
The short answer to the question is no. Washington has the Cascade Subduction Zone, while California is experiencing earthquakes from the San Andreas Fault Zone. While direct triggering is unlikely, large earthquakes can sometimes indirectly affect nearby faults, a phenomenon known as “seismic triggering.” In some cases, a large earthquake on one fault can increase the stress on neighboring faults, potentially making them more likely to slip. However, these effects are generally short-lived, and the probability of a San Andreas earthquake causing a Cascadia earthquake through such indirect effects is considered low.