Earthquake · reviewed by a seismologist
M 1.7ml
Earthquake near Ventura, CA
No earthquake was likely felt in Ventura in the 24 hours to 4:09 am PST (12:09 UTC). The last one was M 3.8, 50 km (31 mi) ENE, at 8:00 pm PDT on 29 September 2026, estimated intensity II (weak) in town; 199 felt reports to USGS. Every earthquake near Ventura
This page: a magnitude 1.7 earthquake was recorded 6 km (4 mi) west-southwest of Ventura, CA, at 3:58 am PDT on 23 August 2021 (10:58 UTC), 10 km deep.
USGS: 12km WSW of Ventura, CA
9 km (6 mi) WSW of San Buenaventura (Ventura), CA · 90 km (56 mi) WNW of Los Angeles, CA
- When
- 3:58 am PDT on 23 August 2021 ()
- Where
- 6 km (4 mi) west-southwest of Ventura, CA · earthquakes near Ventura
- Magnitude
- M 1.7 (ml)
- Depth
- 10 km below the surface
- Felt
- no reports yet
- Nearest
- Ventura County, 23 km ENE
- Nearest mapped fault
- Oak Ridge fault (offshore), 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 1907 days ago
Earthquake alerts for Ventura, CA
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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 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 7 km (4 mi) from the epicentre. In Ventura, 6 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: Ventura 6 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
- Around the size people start to feel M 3.0 89× the energy of this one
- This earthquake M 1.7 about 11 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 4.1 on 2016-03-12 — about 4,400 times the energy of this one.
Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:
- 6.8 The 1925 Santa Barbara, California Earthquake · 42 km W of this epicentre
- 5.5 30 km SW of Channel Islands Beach, California · 31 km SSW of this epicentre
- 5.5 10 km NE of Toro Canyon, California · 31 km NNW of this epicentre
- 5.5 The 1941 Santa Barbara, California Earthquake · 21 km WNW of this epicentre
- 5.3 The 1973 Point Mugu, California Earthquake · 41 km SE 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 34.2490, -119.3512. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Ventura County, CA | 23 km (15 mi) | ENE | earthquakes near Ventura County |
| Santa Barbara County, CA | 71 km (44 mi) | WNW | earthquakes near Santa Barbara County |
| Los Angeles County, CA | 100 km (62 mi) | E | earthquakes near Los Angeles 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.
- 1.9 1km WSW of Goleta, CA
- 2.3 16km SSE of Port Hueneme, CA
- 2.4 19km SSE of Port Hueneme, CA
- 2.4 19km SSE of Port Hueneme, CA
- 2.5 20km SSE of Port Hueneme, CA
- 1.6 25km SSW of Frazier Park, CA
- 1.8 18km SSW of Santa Barbara, CA
- 1.9 8km NW of Malibu, CA
- 1.9 18km SSW of Santa Cruz Is. (E end), CA
- 1.5 20km NNE of Carpinteria, CA
- 1.9 4km WSW of Ojai, CA
- 3.2 5km WSW of Ojai, CA
- 1.7 4km SSW of Moorpark, CA
- 1.8 25km NNE of Montecito, CA
- 2.0 8km NW of Fillmore, 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.