QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5md

6km E of Atascadero, CA

· -0.3 km deep · released about 6.2 lb of TNT

Felt it? Tell USGS Check my area
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
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 1698 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

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.

Where

Epicentre 35.4823, -120.5995. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Luis Obispo County, CA 17 km (11 mi) NW of here earthquakes near San Luis Obispo County
Kings County, CA 96 km (60 mi) SW of here earthquakes near Kings County
Monterey County, CA 106 km (66 mi) SE of here earthquakes near Monterey County
Santa Barbara County, CA 117 km (73 mi) NNW of here 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.3 on 2019-12-17 — it released about 13,000 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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