Earthquake near San Juan Bautista, CA

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 29 km (18 mi) from the epicentre. In San Juan Bautista, 4 km away, the estimate is intensity III (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.

Likely felt in: Prunedale 10 km, intensity III · Hollister 16 km, intensity II · Watsonville 17 km, intensity II · Gilroy 19 km, intensity II · Salinas 19 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 570 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 27,000× the energy of this one
2. Magna, Utah 2020 M 5.7 19,000× the energy of this one
3. Around the size people start to feel M 3.0 1.7× the energy of this one
4. This earthquake M 2.9 about 570 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 4.7 on 2019-10-15 — about 620 times the energy of this one.

Before 2016, the USGS record lists 27 earthquakes of M5 or more within 50 km; the five largest:

1. 6.9 The 1989 Loma Prieta, California Earthquake · 34 km NW of this epicentre Oct 18, 1989
2. 6.5 Near Morgan Hill, California · 31 km N of this epicentre Jul 1, 1911
3. 6.1 Near San Jose, California · 45 km NNW of this epicentre Jun 11, 1903
4. 5.9 10 km SE of Tres Pinos, California · 34 km ESE of this epicentre Apr 9, 1961
5. 5.8 Near Watsonville, California · 16 km NW of this epicentre Mar 11, 1910

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 36.8373, -121.5827. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 2.1 6km SW of Gilroy, CA 06:00 UTC
2. 2.0 2km WNW of San Juan Bautista, CA 10:54 UTC
3. 1.5 6km NNW of Pinnacles, CA 23:24 UTC
4. 1.9 6km NNW of Pinnacles, CA 11:34 UTC
5. 2.4 6km NW of Pinnacles, CA 04:31 UTC
6. 2.6 6km NW of Pinnacles, CA 04:31 UTC
7. 3.1 7km NNW of Pinnacles, CA 04:09 UTC
8. 2.1 6km NNW of Pinnacles, CA 00:28 UTC
9. 1.7 6km NW of Pinnacles, CA 22:35 UTC
10. 4.1 7km NW of Pinnacles, CA 20:51 UTC
11. 3.2 8km NNW of Pinnacles, CA 20:51 UTC
12. 1.8 7km NNW of Pinnacles, CA 07:32 UTC
13. 1.5 8km ENE of Gilroy, CA 12:49 UTC
14. 1.7 7km WSW of Gilroy, CA 10:00 UTC
15. 1.6 16km SSE of Tres Pinos, CA 21:05 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 06:46 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.