QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Paso Robles, CA

No earthquake was likely felt in Paso Robles in the 24 hours to 6:27 am PST (14:27 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 2.1 earthquake was recorded 46 km (29 mi) north-northwest of Paso Robles, CA, at 11:03 pm PDT on 20 May 2021 (06:03 UTC), 10 km deep.

USGS: 8km E of San Ardo, CA

11:03 pm PDT, May 20, 2021 · · 10 km deep · released about 40 lb of TNT

Every earthquake near Paso Robles Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Monterey County 50 kmSan Benito County 69 kmSan Luis Obispo County 79 kmKings County 90 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
11:03 pm PDT on 20 May 2021 ()
Where
46 km (29 mi) north-northwest of Paso Robles, CA · earthquakes near Paso Robles
Magnitude
M 2.1 (md)
Depth
10 km below the surface
Felt
no reports yet
Nearest
Monterey County, 50 km WNW
Nearest mapped fault
San Andreas fault, 15 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 2000 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 13 km (8 mi) from the epicentre. In Paso Robles, 46 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 40 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 2,100 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 10 km NE of San Simeon, California · 45 km SW of this epicentre
  2. 6.4 1901 Parkfield, California Earthquake · 29 km E of this epicentre
  3. 6.0 2004 Parkfield, California Earthquake · 47 km ESE of this epicentre
  4. 5.8 29 km NE of San Lucas, California · 30 km N of this epicentre
  5. 5.8 1934 Parkfield, California Earthquake · 25 km SE 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 36.0310, -120.8205. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Monterey County, CA 50 km (31 mi) WNW earthquakes near Monterey County
San Benito County, CA 69 km (43 mi) NNW earthquakes near San Benito County
San Luis Obispo County, CA 79 km (49 mi) SSE earthquakes near San Luis Obispo County
Kings County, CA 90 km (56 mi) E earthquakes near Kings County
Fresno County, CA 132 km (82 mi) NE earthquakes near Fresno County
Santa Cruz County, CA 152 km (95 mi) NW earthquakes near Santa Cruz County

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

Aftershocks so far

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

  1. 1.7 20km SW of New Idria, CA
  2. 1.8 25km NW of Parkfield, CA
  3. 1.9 23km NW of Parkfield, CA
  4. 1.6 19km NNW of Coalinga, CA
  5. 1.6 5km NW of Parkfield, CA
  6. 2.4 19km NNW of San Simeon, CA
  7. 2.6 2km SSE of Parkfield, CA
  8. 2.1 13km NW of Parkfield, CA
  9. 1.9 23km NNE of San Ardo, CA
  10. 1.6 16km SE of Pinnacles, CA
  11. 1.7 20km NW of Parkfield, CA
  12. 1.9 23km SE of Pinnacles, CA
  13. 2.3 3km SE of San Ardo, CA
  14. 2.8 9km WNW of Templeton, CA
  15. 2.3 20km SW of New Idria, 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.