QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5md

Earthquake near Atascadero, CA

No earthquake was likely felt in Atascadero in the 24 hours to 8:04 am PST (16:04 UTC). The last one was M 2.1, 8 km (5 mi) SW, at 6:08 am PDT on 21 October 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Atascadero

No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.5 quarry blast was recorded 6 km (4 mi) east of Atascadero, CA, at 10:44 am PST on 2 February 2022 (18:44 UTC), less than 1 km deep.

USGS: 6km E of Atascadero, CA

10:44 am PST, Feb 2, 2022 · · -0.3 km deep · released about 6.2 lb of TNT

10 km30 km60 km120 km N San Luis Obispo County 17 kmKings County 96 kmMonterey County 106 kmSanta Barbara County 117 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
10:44 am PST on 2 February 2022 ()
Where
6 km (4 mi) east of Atascadero, CA · earthquakes near Atascadero
Magnitude
M 1.5 (md)
Depth
-0.3 km below the surface
Felt
no reports yet
Nearest
San Luis Obispo County, 17 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1744 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 10 km (6 mi) from the epicentre. In Atascadero, 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: Atascadero 6 km, intensity II. Estimated for each town centre; each link is that town's own record.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 6.2 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.5 about 6.2 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 4.3 on 2019-12-17 — about 13,000 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 1922 Parkfield, California Earthquake · 43 km NE of this epicentre
  2. 6.0 2004 Parkfield, California Earthquake · 43 km NNE of this epicentre
  3. 5.8 1934 Parkfield, California Earthquake · 41 km N of this epicentre
  4. 5.5 1966 Parkfield, California Earthquake · 44 km NE of this epicentre
  5. 5.1 13km N of San Miguel, CA · 44 km N 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 35.4823, -120.5995. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Luis Obispo County, CA 17 km (11 mi) SE earthquakes near San Luis Obispo County
Kings County, CA 96 km (60 mi) NE earthquakes near Kings County
Monterey County, CA 106 km (66 mi) NW earthquakes near Monterey County
Santa Barbara County, CA 117 km (73 mi) SSE earthquakes near Santa Barbara County

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

Aftershocks so far

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

  1. 1.9 9km W of Templeton, CA
  2. 1.6 11km WSW of Templeton, CA
  3. 1.6 16km N of Cayucos, CA
  4. 1.6 2km SSE of Parkfield, CA
  5. 2.4 3km SSE of Parkfield, CA
  6. 1.9 14km SSW of Baywood-Los Osos, CA
  7. 2.8 9km WNW of Templeton, CA
  8. 1.8 13km NE of San Simeon, CA
  9. 1.8 8km WNW of Templeton, CA
  10. 1.5 12km NNE of Cambria, CA
  11. 1.5 6km NE of Santa Margarita, CA
  12. 1.6 11km NE of Cambria, CA
  13. 2.1 10km NNW of Cholame, CA
  14. 1.5 4km E of San Luis Obispo, CA
  15. 1.6 9km NNW of Avila 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

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