Earthquake near Boulder Creek, CA

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Boulder Creek, 13 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: Saratoga, Loyola, Brookdale, Cupertino, Monte Sereno, Los Altos Hills.

How big was it?

This earthquake released about 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
3. Around the size people start to feel M 3.0 170× the energy of this one
4. This earthquake M 1.5 about 5.7 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 4.1 on 2017-10-10 — about 7,200 times the energy of this one.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

1. 6.9 The 1989 Loma Prieta, California Earthquake · 34 km SE of this epicentre Oct 18, 1989
2. 6.3 22 km S of Davenport, California · 47 km S of this epicentre Oct 22, 1926
3. 6.3 16 km SW of Davenport, California · 37 km SSW of this epicentre Oct 22, 1926
4. 6.2 Near San Jose, California · 35 km ENE of this epicentre Aug 3, 1903
5. 6.2 The 1984 Morgan Hill, California Earthquake · 45 km ENE of this epicentre Apr 24, 1984

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 37.2310, -122.1827. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 1.7 6km SSE of Portola Valley, CA 14:52 UTC
2. 1.7 9km NNE of Alum Rock, CA 23:54 UTC
3. 2.9 5km NE of Alum Rock, CA 10:17 UTC
4. 1.6 3km WSW of Portola Valley, CA 02:47 UTC
5. 2.0 3km WSW of Portola Valley, CA 02:01 UTC
6. 1.5 15km E of Seven Trees, CA 04:20 UTC
7. 1.8 8km NE of Alum Rock, CA 03:34 UTC
8. 2.3 16km N of Morgan Hill, CA 23:18 UTC
9. 1.6 9km NE of Alum Rock, CA 22:51 UTC
10. 2.2 15km N of Morgan Hill, CA 02:52 UTC
11. 1.5 3km NE of Union City, CA 04:41 UTC
12. 2.6 12km W of Saratoga, CA 11:13 UTC
13. 1.6 3km ESE of Hayward, CA 04:48 UTC
14. 2.0 6km S of Loyola, CA 04:00 UTC
15. 1.8 2km SE of Pacifica, CA 09:06 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 16:37 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.