Earthquake near Day Valley, CA

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 16 km (10 mi) from the epicentre. In Day Valley, 8 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Lexington Hills, Corralitos, Aptos, Seacliff, Rio Del Mar, Aptos Hills-Larkin Valley.

How big was it?

This earthquake released about 31 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 480,000× the energy of this one
2. Magna, Utah 2020 M 5.7 340,000× the energy of this one
3. Around the size people start to feel M 3.0 31× the energy of this one
4. This earthquake M 2.0 about 31 lb of TNT

Energy from the Gutenberg–Richter relation (log₁₀E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.2 on 2021-01-17 — about 1,900 times the energy of this one.

Before 2016, the USGS record lists 30 earthquakes of M5 or more within 50 km; the five largest:

1. 6.9 The 1989 Loma Prieta, California Earthquake · 9 km SSW of this epicentre Oct 18, 1989
2. 6.5 Near Morgan Hill, California · 18 km E of this epicentre Jul 1, 1911
3. 6.3 22 km S of Davenport, California · 46 km SW of this epicentre Oct 22, 1926
4. 6.3 16 km SW of Davenport, California · 49 km WSW of this epicentre Oct 22, 1926
5. 6.2 Near San Jose, California · 22 km N of this epicentre Aug 3, 1903

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 37.1085, -121.8425. Map © OpenStreetMap contributors.

Nearby places

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

51 earthquakes have been recorded within 50 km since this one.

1. 1.9 10km E of Alum Rock, CA 14:06 UTC
2. 2.8 3km SSW of San Juan Bautista, CA 13:06 UTC
3. 2.7 9km ENE of San Martin, CA 15:24 UTC
4. 1.6 5km NNW of Aromas, CA 01:45 UTC
5. 2.0 6km SSE of Portola Valley, CA 11:51 UTC
6. 2.2 6km S of San Juan Bautista, CA 23:15 UTC
7. 1.6 15km E of Seven Trees, CA 09:08 UTC
8. 2.5 3km WSW of San Juan Bautista, CA 12:48 UTC
9. 1.9 3km WSW of Cupertino, CA 08:39 UTC
10. 1.7 2km ENE of Aromas, CA 18:18 UTC
11. 1.7 28km ENE of Alum Rock, CA 01:35 UTC
12. 1.8 9km ENE of Morgan Hill, CA 18:27 UTC
13. 3.4 14km ESE of Alum Rock, CA 22:55 UTC
14. 1.8 2km WNW of Los Altos Hills, CA 21:11 UTC
15. 2.0 11km W of Moss Landing, CA 04:00 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 07:48 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

• The official USGS event page — the source of record for every value above
• Did you feel it? Report it to USGS — reports go to USGS, not to us
• ShakeMap for this event, when USGS has produced one

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.