2km NW of Signal Hill, CA

2023-05-31 08:54 UTC · 7.0 km deep · released about 40 lb of TNT

Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.

When: 2023-05-31 08:54 UTC
Magnitude: M 2.1 (ml)
Depth: 7.0 km below the surface
Felt: 95 reports · strongest reported intensity IV
Nearest: Orange County, 41 km ESE
Status: Reviewed by a seismologist

USGS · last changed by USGS 1207 days ago · we first saw it 1207 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 95 people have reported feeling it to USGS.

How big was it?

This earthquake released about 40 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 380,000× the energy of this one
Magna, Utah 2020 M 5.7 270,000× the energy of this one
Around the size people start to feel M 3.0 24× the energy of this one
This earthquake M 2.1 about 40 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.

Where

Map loads when it scrolls into view

Epicentre 33.8180, -118.1812. Map © OpenStreetMap contributors.

Nearby places

Place	Distance	Direction
Orange County, CA	41 km (25 mi)	WNW of here	earthquakes near Orange County
Los Angeles County, CA	43 km (27 mi)	S of here	earthquakes near Los Angeles County
Ventura County, CA	106 km (66 mi)	SE of here	earthquakes near Ventura County

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

Aftershocks so far

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

1.9 6 km NNW of Yorba Linda, CA 08:34 UTC
2.6 0 km NNW of View Park-Windsor Hills, CA 15:06 UTC
1.8 0 km N of View Park-Windsor Hills, CA 12:05 UTC
1.6 20 km S of San Pedro, CA 09:16 UTC
1.6 22 km SSW of Seal Beach, CA 05:57 UTC
1.6 2 km NNE of Placentia, CA 02:02 UTC
2.5 5 km ESE of Inglewood, CA 21:30 UTC
1.6 0 km W of View Park-Windsor Hills, CA 16:55 UTC
1.6 4 km ESE of Gardena, CA 07:17 UTC
1.9 10 km WSW of Newport Beach, CA 17:13 UTC
2.0 3 km NW of Placentia, CA 02:47 UTC
2.0 1 km WNW of Huntington Park, CA 03:34 UTC
2.1 1 km SSE of View Park-Windsor Hills, CA 02:56 UTC
2.0 3 km S of Encino, CA 07:40 UTC
2.6 23 km SSW of Newport Beach, CA 18:48 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 12:53 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 4.5 on 2020-09-19 — it released about 4,900 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.