QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Atascadero, CA

No earthquake was likely felt in Atascadero in the 24 hours to 5:45 am PST (13:45 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

This page: a magnitude 1.7 earthquake was recorded 7 km (5 mi) west of Atascadero, CA, at 7:13 am PDT on 10 August 2018 (14:13 UTC), 4.4 km deep.

USGS: 7km W of Atascadero, CA

68 km (42 mi) NNW of Santa Maria, CA

7:13 am PDT, Aug 10, 2018 · · 4.4 km deep · released about 10 lb of TNT

10 km30 km60 km120 km N San Luis Obispo County 30 kmMonterey County 98 kmKings County 107 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
7:13 am PDT on 10 August 2018 ()
Where
7 km (5 mi) west of Atascadero, CA · earthquakes near Atascadero
Magnitude
M 1.7 (md)
Depth
4.4 km below the surface
Felt
no reports yet
Nearest
San Luis Obispo County, 30 km ESE
Nearest mapped fault
Los Osos fault, 20 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 3011 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 11 km (7 mi) from the epicentre. In Atascadero, 7 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 7 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 10 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 1,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 92× the energy of this one
  4. This earthquake M 1.7 about 10 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 10 km NE of San Simeon, California · 39 km NW of this epicentre
  2. 5.8 1934 Parkfield, California Earthquake · 40 km N of this epicentre
  3. 5.7 Southwest of Cambria, California · 40 km W of this epicentre
  4. 5.1 13km N of San Miguel, CA · 43 km N of this epicentre
  5. 5.0 11 km NNE of Shandon, California · 48 km NE 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 35.4898, -120.7528. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Luis Obispo County, CA 30 km (18 mi) ESE earthquakes near San Luis Obispo County
Monterey County, CA 98 km (61 mi) NNW earthquakes near Monterey County
Kings County, CA 107 km (66 mi) NE earthquakes near Kings County
Santa Barbara County, CA 124 km (77 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

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

  1. 1.6 7km E of Atascadero, CA
  2. 2.5 3km NNW of Avila Beach, CA
  3. 1.7 6km NNE of Santa Margarita, CA
  4. 1.7 9km SSW of Atascadero, CA
  5. 1.5 10km NE of San Simeon, CA
  6. 2.0 10km SW of Baywood-Los Osos, CA
  7. 2.0 20km WNW of Lake Nacimiento, CA
  8. 1.5 14km ENE of San Simeon, CA
  9. 1.5 15km SE of Shandon, CA
  10. 1.6 14km ENE of San Simeon, CA
  11. 1.5 14km ENE of San Simeon, CA
  12. 1.6 6km E of Atascadero, CA
  13. 1.7 14km ENE of San Simeon, CA
  14. 2.3 10km NE of San Simeon, CA
  15. 1.9 8km WSW of Atascadero, 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.