Earthquake · reviewed by a seismologist
M 4.0mw
Earthquake near Westmorland, CA
No earthquake was likely felt in Westmorland in the 24 hours to 1:26 am PST (09:26 UTC). The last one was M 4.9, 79 km (49 mi) SSE, at 10:27 am PST on 3 November 2026, estimated intensity III (weak) in town; 321 felt reports to USGS. Every earthquake near Westmorland
This page: a magnitude 4.0 earthquake was recorded 16 km (10 mi) southwest of Westmorland, CA, at 9:21 am PDT on 31 July 2016 (16:21 UTC), 3.2 km deep. 42 people have reported feeling it to USGS.
USGS: 16km SW of Westmorland, CA
- When
- 9:21 am PDT on 31 July 2016 ()
- Where
- 16 km (10 mi) southwest of Westmorland, CA · earthquakes near Westmorland
- Magnitude
- M 4.0 (mw)
- Depth
- 3.2 km below the surface
- Felt
- 42 reports · strongest reported intensity IV
- Measured shaking
- intensity VI (ShakeMap)
- USGS impact alert
- green
- Nearest
- Imperial County, 39 km ENE
- Nearest mapped fault
- San Jacinto fault, 2 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 3676 days ago
Earthquake alerts for Westmorland, CA
Get a notification in this browser when USGS records an earthquake near Westmorland, CA. No account or email needed.
Alerts are on for .
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 light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
At this magnitude and depth, people at rest would likely notice it out to about 99 km (62 mi) from the epicentre. In Westmorland, 16 km away, the estimate is intensity III (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: Brawley 22 km, intensity III · Imperial 22 km, intensity III · El Centro 26 km, intensity III · Calipatria 30 km, intensity III · Holtville 39 km, intensity III · Calexico 40 km, intensity III · Salton City 42 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 17 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 10,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 450× the energy of this one
- Magna, Utah 2020 M 5.7 320× the energy of this one
- This earthquake M 4.0 about 17 tons of TNT
- Around the size people start to feel M 3.0 this one released 35× 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 (31 mi) since our catalogue begins in 2016. No other earthquake of M4 or more has been recorded this close in that time.
Before 2016, the USGS record lists 42 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 The 1940 Imperial Valley, California Earthquake · 38 km ESE of this epicentre
- 6.6 The 1942 Fish Creek Mountains, California Earthquake · 3 km NW of this epicentre
- 6.6 The 1968 Borrego Mountain, California Earthquake · 40 km NW of this epicentre
- 6.6 The 1987 Superstition Hills, California Earthquake · 11 km NW of this epicentre
- 6.4 The 1954 San Jacinto Fault, California Earthquake · 48 km NW 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 32.9583, -115.7605. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Imperial County, CA | 39 km (24 mi) | ENE | earthquakes near Imperial County |
| Riverside County, CA | 89 km (55 mi) | NNW | earthquakes near Riverside County |
| San Diego County, CA | 95 km (59 mi) | W | earthquakes near San Diego County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
57 earthquakes have been recorded within 50 km since this one.
- 1.8 14km WNW of Calipatria, CA
- 2.2 9km ENE of Ocotillo Wells, CA
- 1.7 13km WNW of Calipatria, CA
- 1.6 13km WNW of Calipatria, CA
- 1.5 12km SSE of Bombay Beach, CA
- 2.1 7km NE of Imperial, CA
- 2.4 20km SW of Ocotillo Wells, CA
- 2.4 14km N of Ocotillo Wells, CA
- 1.7 12km WNW of Progreso, B.C., MX
- 3.1 14km N of Ocotillo Wells, CA
- 1.8 14km N of Ocotillo Wells, CA
- 1.8 14km N of Ocotillo Wells, CA
- 2.0 9km NE of Ocotillo Wells, CA
- 1.7 16km W of Progreso, B.C., MX
- 1.6 6km SSE of Bombay Beach, 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.