QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2ml

Earthquake near Simi Valley, CA

No earthquake was likely felt in Simi Valley in the 24 hours to 7:17 am PST (15:17 UTC). The last one was M 2.3, 17 km (10 mi) E, at 9:45 am PST on 7 November 2026, estimated intensity II (weak) in town; 26 felt reports to USGS. Every earthquake near Simi Valley

This page: a magnitude 2.2 earthquake was recorded 6 km (4 mi) east of Simi Valley, CA, at 12:47 am PST on 21 December 2018 (08:47 UTC), 9.5 km deep. 9 people have reported feeling it to USGS.

USGS: 2km ENE of Simi Valley, CA

in Simi Valley, CA · 40 km (25 mi) NW of Los Angeles, CA

12:47 am PST, Dec 21, 2018 · · 9.5 km deep · released about 67 lb of TNT

Every earthquake near Simi Valley Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Ventura County 40 kmLos Angeles County 43 kmOrange County 109 kmKern County 119 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
12:47 am PST on 21 December 2018 ()
Where
6 km (4 mi) east of Simi Valley, CA · earthquakes near Simi Valley
Magnitude
M 2.2 (ml)
Depth
9.5 km below the surface
Felt
9 reports · strongest reported intensity III
Nearest
Ventura County, 40 km WNW
Nearest mapped fault
Simi-Santa Rosa fault, 5 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 2883 days ago

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 16 km (10 mi) from the epicentre. In Simi Valley, 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: Simi Valley 6 km, intensity II · Agoura 15 km, intensity II · Moorpark 15 km, intensity II · Thousand Oaks 16 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 67 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 230,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 160,000× the energy of this one
  3. Around the size people start to feel M 3.0 14× the energy of this one
  4. This earthquake M 2.2 about 67 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 710 times the energy of this one.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 Northridge, California, earthquake · 18 km ESE of this epicentre
  2. 6.6 1971 San Fernando Earthquake, California · 35 km ENE of this epicentre
  3. 5.9 1km ENE of Granada Hills, California · 20 km E of this epicentre
  4. 5.8 10km SSW of Agua Dulce, CA · 35 km ENE of this epicentre
  5. 5.8 10km SSW of Agua Dulce, CA · 35 km ENE 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 34.2757, -118.7147. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Ventura County, CA 40 km (25 mi) WNW earthquakes near Ventura County
Los Angeles County, CA 43 km (26 mi) ESE earthquakes near Los Angeles County
Orange County, CA 109 km (68 mi) SE earthquakes near Orange County
Kern County, CA 119 km (74 mi) N earthquakes near Kern County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

50 earthquakes have been recorded within 50 km since this one.

  1. 2.9 0km SSW of Century City, CA
  2. 1.5 10km N of Piru, CA
  3. 2.0 10km S of Agua Dulce, CA
  4. 1.7 8km NNE of Malibu, CA
  5. 1.5 10km N of Piru, CA
  6. 2.0 3km ESE of Northridge, CA
  7. 2.7 3km ESE of Northridge, CA
  8. 2.1 6km SW of Valencia, CA
  9. 1.7 4km SE of San Fernando, CA
  10. 1.6 10km N of Piru, CA
  11. 1.8 14km N of Fillmore, CA
  12. 1.5 6km N of Pacoima, CA
  13. 1.8 20km SSW of Frazier Park, CA
  14. 1.7 1km NNE of Inglewood, CA
  15. 1.9 2km NNW of Inglewood, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.