Earthquake near North Tustin, CA

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

At this magnitude and depth, people at rest would likely notice it out to about 17 km (11 mi) from the epicentre. In North Tustin, 9 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: North Tustin 9 km, intensity II · Tustin 12 km, intensity II · Orange 14 km, intensity II · Yorba Linda 14 km, intensity II · Corona 16 km, intensity II · Santa Ana 16 km, intensity II · Lake Forest 17 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 43 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.

1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
3. Around the size people start to feel M 3.0 22× the energy of this one
4. This earthquake M 2.1 about 43 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 4.4 on 2018-08-29 — about 2,600 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

1. 6.4 The 1933 Long Beach, California Earthquake · 33 km SW of this epicentre Mar 11, 1933
2. 6.0 The 1910 Lake Elsinore, California Earthquake · 30 km ESE of this epicentre May 15, 1910
3. 5.9 The 1987 Whittier Narrows, California Earthquake · 45 km NW of this epicentre Oct 1, 1987
4. 5.5 The 1990 Upland, California Earthquake · 38 km N of this epicentre Feb 28, 1990
5. 5.4 5km S of Chino Hills, CA · 18 km NNW of this epicentre Jul 29, 2008

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 33.7983, -117.7075. 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. 1.8 6km N of Lake Elsinore, CA 22:02 UTC
2. 1.9 5km S of Rancho Cucamonga, CA 14:14 UTC
3. 1.7 7km NNE of San Dimas, CA 16:30 UTC
4. 2.3 7km NNE of San Dimas, CA 16:29 UTC
5. 1.6 11km WSW of Newport Beach, CA 02:25 UTC
6. 1.6 4km NNW of Signal Hill, CA 13:08 UTC
7. 1.6 3km SE of Home Gardens, CA 21:30 UTC
8. 1.7 4km W of Lake Elsinore, CA 10:40 UTC
9. 1.9 3km SW of San Bernardino, CA 07:46 UTC
10. 1.6 1km SSW of Colton, CA 11:22 UTC
11. 1.5 5km SSE of Home Gardens, CA 17:37 UTC
12. 1.5 2km NE of Whittier, CA 07:48 UTC
13. 2.0 4km SSW of La Mirada, CA 07:13 UTC
14. 2.3 3km SW of La Mirada, CA 14:52 UTC
15. 1.5 11km NE of Trabuco Canyon, CA 21:59 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 14:55 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.