Earthquake · reviewed by a seismologist
M 2.3ml
Earthquake near Costa Mesa, CA
No earthquake was likely felt in Costa Mesa in the 24 hours to 12:14 am PST (08:14 UTC). The last one was M 3.2, 29 km (18 mi) WNW, at 12:44 am PDT on 9 October 2026, estimated intensity II (weak) in town; 1,090 felt reports to USGS. Every earthquake near Costa Mesa
This page: a magnitude 2.3 earthquake was recorded 5 km (3 mi) north-northeast of Costa Mesa, CA, at 10:55 pm PDT on 28 August 2016 (05:55 UTC), 15 km deep. 8 people have reported feeling it to USGS.
USGS: 2km NNE of Costa Mesa, CA
in Costa Mesa, CA · 60 km (37 mi) SE of Los Angeles, CA
- When
- 10:55 pm PDT on 28 August 2016 ()
- Where
- 5 km (3 mi) north-northeast of Costa Mesa, CA · earthquakes near Costa Mesa
- Magnitude
- M 2.3 (ml)
- Depth
- 15 km below the surface
- Felt
- 8 reports · strongest reported intensity III
- Nearest
- Orange County, 12 km E
- Nearest mapped fault
- San Joaquin Hills thrust, 1 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 3718 days ago
Earthquake alerts for Costa Mesa, CA
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Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 13 km (8 mi) from the epicentre. In Costa Mesa, 5 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: Costa Mesa 5 km, intensity II · Fountain Valley 5 km, intensity II · Newport Beach 7 km, intensity II · Santa Ana 8 km, intensity II · Irvine 8 km, intensity II · Huntington Beach 9 km, intensity II · Tustin 10 km, intensity II · Garden Grove 11 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 88 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 170,000× the energy of this one
- Magna, Utah 2020 M 5.7 120,000× the energy of this one
- Around the size people start to feel M 3.0 11× the energy of this one
- This earthquake M 2.3 about 88 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 The 1933 Long Beach, California Earthquake · 10 km SW of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 47 km E of this epicentre
- 5.9 The 1987 Whittier Narrows, California Earthquake · 45 km NNW of this epicentre
- 5.4 5km S of Chino Hills, CA · 32 km NNE of this epicentre
- 5.3 7km W of Newport Beach, CA · 11 km SW of this epicentre
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 33.6823, -117.9080. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 12 km (8 mi) | E | earthquakes near Orange County |
| Los Angeles County, CA | 66 km (41 mi) | NNW | earthquakes near Los Angeles County |
| San Diego County, CA | 128 km (80 mi) | SE | earthquakes near San Diego County |
| Ventura County, CA | 136 km (84 mi) | NW | earthquakes near Ventura County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
52 earthquakes have been recorded within 50 km since this one.
- 2.2 2km ENE of Inglewood, CA
- 2.4 1km ENE of Brea, CA
- 1.7 7km WSW of Huntington Beach, CA
- 1.6 2km N of Costa Mesa, CA
- 2.1 7km WSW of Huntington Beach, CA
- 1.8 18km SSW of Rancho Palos Verdes, CA
- 1.6 4km SE of Home Gardens, CA
- 1.7 6km SW of Chino Hills, CA
- 1.6 4km N of Yorba Linda, CA
- 1.5 2km SE of Home Gardens, CA
- 1.6 7km SSE of Home Gardens, CA
- 1.6 4km WSW of Compton, CA
- 2.5 2km NNE of Costa Mesa, CA
- 1.5 5km SE of Home Gardens, CA
- 1.5 7km SSE of Home Gardens, CA
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . 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.