QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2md

Earthquake near Portola, CA

No earthquake was likely felt in Portola in the 24 hours to 11:38 am PST (19:38 UTC). The last one was M 2.7, 8 km (5 mi) N, at 8:16 am PST on 10 November 2026, estimated intensity III (weak) in town; 9 felt reports to USGS. Every earthquake near Portola

This page: a magnitude 2.2 earthquake was recorded 11 km (7 mi) southwest of Portola, CA, at 4:48 pm PDT on 16 October 2023 (23:48 UTC), 3.2 km deep.

USGS: 0 km ESE of Clio, CA

65 km (41 mi) WNW of Reno, NV

4:48 pm PDT, Oct 16, 2023 · · 3.2 km deep · released about 60 lb of TNT

Every earthquake near Portola Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sierra County 19 kmPlumas County 35 kmNevada County 53 kmPlacer County 77 kmYuba County 85 kmButte County 89 kmStorey County 96 kmCarson City 96 kmEl Dorado 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
4:48 pm PDT on 16 October 2023 ()
Where
11 km (7 mi) southwest of Portola, CA · earthquakes near Portola
Magnitude
M 2.2 (md)
Depth
3.2 km below the surface
Felt
no reports yet
Nearest
Sierra County, 19 km SSE
Nearest mapped fault
Mohawk Valley fault, 3 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 1122 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 18 km (11 mi) from the epicentre. In Portola, 11 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: Portola 11 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 60 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 250,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 180,000× the energy of this one
  3. Around the size people start to feel M 3.0 16× the energy of this one
  4. This earthquake M 2.2 about 60 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 4.7 on 2021-05-07 — about 4,700 times the energy of this one.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.0 6 km WNW of Verdi, California · 47 km ESE of this epicentre
  2. 5.9 West of Downieville, California · 46 km SW of this epicentre
  3. 5.9 9 km NW of Truckee, California · 47 km SE of this epicentre
  4. 5.6 5 km NE of Loyalton, California · 32 km E of this epicentre
  5. 5.3 11 km N of Soda Springs, California · 38 km SSE 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 39.7442, -120.5683. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sierra County, CA 19 km (12 mi) SSE earthquakes near Sierra County
Plumas County, CA 35 km (22 mi) NW earthquakes near Plumas County
Nevada County, CA 53 km (33 mi) SSW earthquakes near Nevada County
Placer County, CA 77 km (48 mi) S earthquakes near Placer County
Yuba County, CA 85 km (53 mi) SW earthquakes near Yuba County
Butte County, CA 89 km (55 mi) W earthquakes near Butte County

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

Aftershocks so far

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

  1. 2.8 0 km SW of Mohawk Vista, CA
  2. 1.8 16 km WSW of Doyle, California
  3. 2.1 4 km NW of Spring Garden, CA
  4. 1.7 2 km NNE of Portola, California
  5. 2.1 20 km NNW of Truckee, CA
  6. 2.4 16 km SW of Loyalton, CA
  7. 1.5 6 km SE of Beckwourth, California
  8. 2.3 18 km NNW of Truckee, CA
  9. 2.9 0 km NNE of Whitehawk, CA
  10. 2.3 4 km S of Cromberg, CA
  11. 2.4 17 km N of Truckee, CA
  12. 1.5 9 km SSE of Sierraville, California
  13. 1.7 4 km SW of Sierra Brooks, California
  14. 1.7 7 km ENE of East Quincy, California
  15. 2.2 4 km NNW of Spring Garden, 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.