EarthQuake Watch
California earthquakes, reported plainly.

M4.6 earthquake near Boulder Creek felt by 8 million across Bay Area

An M4.6 earthquake struck 1 km southeast of Boulder Creek, California on April 2, 2026 at 1:41 AM PDT (08:41:25 UTC). USGS placed the epicenter in Santa Cruz County at a depth of 10.4 kilometers, about 1.7 km from the mapped trace of the Zayante-Vergeles fault zone.

USGS PAGER estimated that approximately 8.05 million people were within range of light shaking (MMI ≥3), with about 42,900 experiencing moderate shaking (MMI ≥5). PAGER issued a green alert, meaning no significant damage or casualties are expected.

The event drew 33,073 "Did You Feel It?" reports submitted to USGS — the highest count of any California earthquake in the preceding 30 days. Community-reported intensity (CDI) was 5.8 and instrumental intensity (MMI) was 5.7, values consistent with light-to-moderate shaking.

USGS catalog data shows no other M4.6+ earthquakes within 20 km of this epicenter in the past 10 years, making the event unusual for the location.

At a depth of 10.4 km, the event sits on the boundary between shallow-crustal and mid-crustal activity. Shallower earthquakes tend to produce stronger surface shaking. USGS assigned the event a significance score of 904 on its internal 0–1000 scale — the top score in the California catalog for the past month.

Event data

USGS canonical event page →

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