QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Cambria, CA

No earthquake was likely felt in Cambria in the 24 hours to 8:15 am PST (16:15 UTC). The last one was M 2.3, 18 km (11 mi) NNE, at 5:04 pm PDT on 21 September 2026, estimated intensity II (weak) in town. Every earthquake near Cambria

This page: a magnitude 1.7 earthquake was recorded 31 km (19 mi) northwest of Cambria, CA, at 4:31 am PST on 22 December 2021 (12:31 UTC), 4.0 km deep.

USGS: 18km NNW of San Simeon, CA

4:31 am PST, Dec 22, 2021 · · 4.0 km deep · released about 12 lb of TNT

10 km30 km60 km120 km N Monterey County 51 kmSan Luis Obispo County 88 kmSan Benito County 94 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
4:31 am PST on 22 December 2021 ()
Where
31 km (19 mi) northwest of Cambria, CA · earthquakes near Cambria
Magnitude
M 1.7 (md)
Depth
4.0 km below the surface
Felt
no reports yet
Nearest
Monterey County, 51 km N
Nearest mapped fault
San Gregorio 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 1778 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 12 km (7 mi) from the epicentre. In Cambria, 31 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.

How big was it?

This earthquake released about 12 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.

  1. Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 870,000× the energy of this one
  3. Around the size people start to feel M 3.0 78× the energy of this one
  4. This earthquake M 1.7 about 12 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 4.7 on 2021-10-25 — about 23,000 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 10 km NE of San Simeon, California · 20 km ESE of this epicentre
  2. 6.2 28km NW of Cambria, CA · 7 km SSW of this epicentre
  3. 5.7 Southwest of Cambria, California · 32 km SSE of this epicentre
  4. 5.2 26km NNW of Lake Nacimiento, CA · 35 km NE of this epicentre
  5. 5.2 25 km NW of San Simeon, California · 8 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 35.7797, -121.2925. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Monterey County, CA 51 km (32 mi) N earthquakes near Monterey County
San Luis Obispo County, CA 88 km (55 mi) ESE earthquakes near San Luis Obispo County
San Benito County, CA 94 km (59 mi) NNE earthquakes near San Benito County

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

Aftershocks so far

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

  1. 1.8 25km SSE of Lopez Point, CA
  2. 2.2 6km NE of San Simeon, CA
  3. 1.7 9km WNW of Templeton, CA
  4. 1.5 8km ENE of San Simeon, CA
  5. 1.9 11km N of Cayucos, CA
  6. 1.8 7km NNE of San Simeon, CA
  7. 1.7 2km SE of San Ardo, CA
  8. 1.8 19km NNW of San Simeon, CA
  9. 1.6 12km NE of San Simeon, CA
  10. 1.6 2km E of Lopez Point, CA
  11. 1.7 8km NE of San Simeon, CA
  12. 1.7 20km NNW of San Simeon, CA
  13. 2.4 18km NNW of San Simeon, CA
  14. 1.6 9km N of Cambria, CA
  15. 2.1 20km SSE of Lopez Point, 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.