Earthquake · reviewed by a seismologist
M 1.8ml
Earthquake near Castaic, CA
No earthquake was likely felt in Castaic in the 24 hours to 2:52 am PST (10:52 UTC). The last one was M 2.2, 11 km (7 mi) S, at 8:32 am PDT on 18 October 2026, estimated intensity II (weak) in town; 16 felt reports to USGS. Every earthquake near Castaic
This page: a magnitude 1.8 earthquake was recorded 6 km (4 mi) west-northwest of Castaic, CA, at 7:46 pm PST on 8 December 2018 (03:46 UTC), 17 km deep. 1 person has reported feeling it to USGS.
USGS: 6km WNW of Castaic, CA
59 km (37 mi) NNW of Los Angeles, CA · 19 km (12 mi) WNW of Santa Clarita, CA
- When
- 7:46 pm PST on 8 December 2018 ()
- Where
- 6 km (4 mi) west-northwest of Castaic, CA · earthquakes near Castaic
- Magnitude
- M 1.8 (ml)
- Depth
- 17 km below the surface
- Felt
- 1 report · strongest reported intensity III
- Nearest
- Ventura County, 44 km WSW
- Nearest mapped fault
- San Gabriel fault, 3 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 2893 days ago
Earthquake alerts for Castaic, 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 it was probably too small to be felt, even directly above it. In Castaic, 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.
Earthquakes near other towns within 30 km: Val Verde, Valencia, Piru, Stevenson Ranch, Santa Clarita, Fillmore.
How big was it?
This earthquake released about 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 930,000× the energy of this one
- Magna, Utah 2020 M 5.7 660,000× the energy of this one
- Around the size people start to feel M 3.0 59× the energy of this one
- This earthquake M 1.8 about 16 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 2,900 times the energy of this one.
Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:
- 6.7 Northridge, California, earthquake · 35 km SSE of this epicentre
- 6.6 1971 San Fernando Earthquake, California · 30 km ESE of this epicentre
- 6.0 Tejon Pass, California · 48 km NNW of this epicentre
- 5.9 1km ENE of Granada Hills, California · 31 km SE of this epicentre
- 5.8 10km SSW of Agua Dulce, CA · 30 km ESE 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 34.5037, -118.6818. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Ventura County, CA | 44 km (28 mi) | WSW | earthquakes near Ventura County |
| Los Angeles County, CA | 52 km (32 mi) | SE | earthquakes near Los Angeles County |
| Kern County, CA | 94 km (58 mi) | N | earthquakes near Kern County |
| Orange County, CA | 124 km (77 mi) | SE | earthquakes near Orange County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
47 earthquakes have been recorded within 50 km since this one.
- 1.9 7km SSW of Agoura Hills, CA
- 1.5 3km NW of Frazier Park, CA
- 1.5 8km E of Lebec, CA
- 1.6 15km N of Fillmore, CA
- 1.8 17km SSW of Gorman, CA
- 1.9 18km S of Frazier Park, CA
- 2.2 3km NW of Frazier Park, CA
- 1.7 14km NE of Ojai, CA
- 2.3 15km NE of Ojai, CA
- 1.5 10km N of Piru, CA
- 1.7 16km NE of Ojai, CA
- 2.0 10km S of Agua Dulce, CA
- 1.7 8km NNE of Malibu, CA
- 1.5 10km N of Piru, CA
- 2.0 3km ESE of Northridge, 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.