QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

Earthquake near Paso Robles, CA

No earthquake was likely felt in Paso Robles in the 24 hours to 8:06 am PST (16:06 UTC). The last one was M 2.5, 21 km (13 mi) S, at 11:41 pm PDT on 15 August 2026, estimated intensity II (weak) in town; 61 felt reports to USGS. Every earthquake near Paso Robles

This page: a magnitude 2.7 earthquake was recorded 37 km (23 mi) east-northeast of Paso Robles, CA, at 12:09 pm PDT on 31 July 2021 (19:09 UTC), 8.5 km deep. 3 people have reported feeling it to USGS.

USGS: 7km NNW of Cholame, CA

12:09 pm PDT, Jul 31, 2021 · · 8.5 km deep · released about 380 lb of TNT

Every earthquake near Paso Robles Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Luis Obispo County 45 kmKings County 57 kmMonterey County 102 kmSan Benito County 114 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
12:09 pm PDT on 31 July 2021 ()
Where
37 km (23 mi) east-northeast of Paso Robles, CA · earthquakes near Paso Robles
Magnitude
M 2.7 (md)
Depth
8.5 km below the surface
Felt
3 reports · strongest reported intensity II
Nearest
San Luis Obispo County, 45 km SSW
Nearest mapped fault
San Andreas fault, 1 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 1856 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 24 km (15 mi) from the epicentre. In Paso Robles, 37 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.

Earthquakes near other towns within 30 km: Shandon.

How big was it?

This earthquake released about 380 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 40,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 29,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.5× the energy of this one
  4. This earthquake M 2.7 about 380 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 220 times the energy of this one.

Before 2016, the USGS record lists 14 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 1922 Parkfield, California Earthquake · 8 km ESE of this epicentre
  2. 6.4 1901 Parkfield, California Earthquake · 29 km NNW of this epicentre
  3. 6.0 2004 Parkfield, California Earthquake · 5 km NW of this epicentre
  4. 5.8 1934 Parkfield, California Earthquake · 31 km WNW of this epicentre
  5. 5.6 8 km SW of Huron, California · 43 km NNE 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 35.7807, -120.3330. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Luis Obispo County, CA 45 km (28 mi) SSW earthquakes near San Luis Obispo County
Kings County, CA 57 km (35 mi) NE earthquakes near Kings County
Monterey County, CA 102 km (63 mi) WNW earthquakes near Monterey County
San Benito County, CA 114 km (71 mi) NW earthquakes near San Benito County
Fresno County, CA 125 km (78 mi) NNE earthquakes near Fresno County

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

Aftershocks so far

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

  1. 2.2 6km W of Templeton, CA
  2. 3.3 1km W of Parkfield, CA
  3. 2.5 11km N of Avenal, CA
  4. 1.6 12km NW of Parkfield, CA
  5. 2.2 4km WSW of Paso Robles, CA
  6. 1.7 14km SSW of Avenal, CA
  7. 1.9 14km SSW of Avenal, CA
  8. 1.8 24km NW of Parkfield, CA
  9. 1.5 12km NW of Parkfield, CA
  10. 1.6 23km ENE of San Ardo, CA
  11. 3.2 7km NW of Parkfield, CA
  12. 1.6 0km ENE of Kettleman City, CA
  13. 1.6 8km SSE of Huron, CA
  14. 1.8 22km NW of Parkfield, CA
  15. 2.2 4km ESE of Cholame, 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.