Earthquake near Westhaven-Moonstone, 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 40 km (25 mi) from the epicentre. In Westhaven-Moonstone, 15 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.

Likely felt in: McKinleyville 24 km, intensity II · Bayside 34 km, intensity II · Willow Creek 37 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1,800 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 180,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 8,200× the energy of this one
3. Magna, Utah 2020 M 5.7 5,800× the energy of this one
4. This earthquake M 3.2 about 1,800 lb of TNT
5. Around the size people start to feel M 3.0 this one released 1.9× more

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 4.8 on 2016-07-21 — about 270 times the energy of this one.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

1. 7.2 The 1980 Eureka, California Earthquake · 23 km W of this epicentre Nov 8, 1980
2. 6.4 Northwest of Eureka, California · 46 km WSW of this epicentre Apr 23, 1906
3. 6.4 The 1954 Eureka-Arcata, California Earthquake · 34 km SSE of this epicentre Dec 21, 1954
4. 5.8 Near Eureka, California · 38 km S of this epicentre Aug 18, 1908
5. 5.6 26 km NNW of Willow Creek, California · 16 km E of this epicentre Feb 13, 2012

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 41.1455, -123.9838. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 2.2 3km NW of Willow Creek, CA 09:09 UTC
2. 2.4 20km NW of Bayview, CA 00:19 UTC
3. 2.7 1km NNE of Humboldt Hill, CA 03:02 UTC
4. 2.8 11km NW of Eureka, CA 07:37 UTC
5. 2.8 22km NW of Weitchpec, CA 12:14 UTC
6. 2.2 4km NW of Humboldt Hill, CA 20:32 UTC
7. 2.3 1km ENE of Humboldt Hill, CA 15:17 UTC
8. 2.2 12km E of Blue Lake, CA 20:11 UTC
9. 2.4 20km NE of Willow Creek, CA 15:09 UTC
10. 2.1 9km NW of Willow Creek, CA 02:50 UTC
11. 2.3 15km WSW of Willow Creek, CA 12:45 UTC
12. 2.6 1km SE of McKinleyville, CA 00:25 UTC
13. 3.1 14km SE of Klamath, CA 05:24 UTC
14. 1.8 16km NW of Bayview, CA 15:11 UTC
15. 1.8 13km E of Willow Creek, CA 09:38 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 06:26 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.