4 km SE of Ontario, CA

2024-09-07 17:34 UTC · 4.8 km deep · released about 13 tons 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: 2024-09-07 17:34 UTC
Magnitude: M 4.0 (mw)
Depth: 4.8 km below the surface
Felt: 2758 reports · strongest reported intensity V
Measured shaking: intensity V (ShakeMap)
Tsunami: USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest: Orange County, 43 km SSW
Status: Reviewed by a seismologist

USGS · last changed by USGS 531 days ago · we first saw it 531 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 2758 people have reported feeling it to USGS.

How big was it?

This earthquake released about 13 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

Northridge, California 1994 M 6.7 13,000× the energy of this one
Mineral, Virginia 2011 M 5.8 600× the energy of this one
Magna, Utah 2020 M 5.7 420× the energy of this one
This earthquake M 4.0 about 13 tons of TNT
Around the size people start to feel M 3.0 this one released 27× 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.

Where

Map loads when it scrolls into view

Epicentre 34.0260, -117.5908. Map © OpenStreetMap contributors.

Nearby places

Place	Distance	Direction
Orange County, CA	43 km (26 mi)	NNE of here	earthquakes near Orange County
Los Angeles County, CA	65 km (40 mi)	ESE of here	earthquakes near Los Angeles County
San Diego County, CA	135 km (84 mi)	NW of here	earthquakes near San Diego 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.

1.5 3 km S of Fontana, CA 09:50 UTC
1.8 2 km SSE of Fontana, CA 00:45 UTC
1.7 2 km S of Fontana, CA 16:57 UTC
1.7 2 km NNE of Villa Park, CA 08:14 UTC
1.6 6 km NNE of Fontana, CA 00:54 UTC
1.6 9 km WSW of Lytle Creek, CA 14:26 UTC
1.6 3 km SE of Ontario, CA 19:57 UTC
3.5 2 km SE of Ontario, CA 19:56 UTC
1.7 4 km SE of Ontario, CA 08:43 UTC
1.8 6 km SW of Corona, CA 07:22 UTC
3.1 7 km NW of Glen Avon, CA 23:11 UTC
1.9 8 km SSE of Home Gardens, CA 19:13 UTC
1.5 2 km SSE of Fontana, CA 19:27 UTC
2.3 3 km S of Fontana, CA 14:52 UTC
1.7 3 km S of Fontana, CA 13:41 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 15:25 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 7.7 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.