QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Portola, CA

No earthquake was likely felt in Portola in the 24 hours to 7:22 am PST (15:22 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 1.6 earthquake was recorded 12 km (8 mi) west-northwest of Portola, CA, at 3:24 am PDT on 30 April 2019 (10:24 UTC), 13 km deep.

USGS: 7 km NNE of Plumas Eureka, California

73 km (45 mi) WNW of Reno, NV

3:24 am PDT, Apr 30, 2019 · · 13 km deep · released about 7.6 lb of TNT

10 km30 km60 km120 km N Plumas County 25 kmSierra County 31 kmNevada County 62 kmButte County 87 kmPlacer County 88 kmYuba County 90 kmLassen County 97 kmStorey County 103 kmCarson City 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
3:24 am PDT on 30 April 2019 ()
Where
12 km (8 mi) west-northwest of Portola, CA · earthquakes near Portola
Magnitude
M 1.6 (ml)
Depth
13 km below the surface
Felt
no reports yet
Nearest
Plumas County, 25 km NW
Nearest mapped fault
Mohawk Valley fault, 5 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 2754 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Portola, 12 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: East Quincy.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 4.5 on 2016-08-04 — about 21,000 times the energy of this one.

Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:

  1. 5.6 5 km NE of Loyalton, California · 38 km ESE of this epicentre
  2. 5.3 11 km N of Soda Springs, California · 49 km SSE of this epicentre
  3. 5.3 4 km S of Doyle, California · 45 km ENE of this epicentre
  4. 5.2 3 km N of Blairsden, California · 4 km SSW 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 39.8444, -120.6083. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Plumas County, CA 25 km (15 mi) NW earthquakes near Plumas County
Sierra County, CA 31 km (19 mi) SSE earthquakes near Sierra County
Nevada County, CA 62 km (39 mi) SSW earthquakes near Nevada County
Butte County, CA 87 km (54 mi) WSW earthquakes near Butte County
Placer County, CA 88 km (54 mi) S earthquakes near Placer County
Yuba County, CA 90 km (56 mi) SW earthquakes near Yuba 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. 3.1 5km NE of East Quincy, CA
  2. 1.9 10km N of Spring Garden, CA
  3. 2.3 5km NNE of Little Grass Valley, CA
  4. 2.1 8km W of La Porte, CA
  5. 2.3 22km SW of Whitehawk, CA
  6. 2.8 8km WNW of Lake Davis, CA
  7. 1.8 5km ESE of Taylorsville, CA
  8. 1.8 5km ESE of Taylorsville, CA
  9. 1.6 6 km S of Taylorsville, California
  10. 2.0 21km NW of Truckee, CA
  11. 1.6 8km W of La Porte, CA
  12. 1.5 8 km ESE of Milford, California
  13. 2.4 5km SE of Chilcoot-Vinton, CA
  14. 2.8 1km WNW of Twain, CA
  15. 1.5 6 km SSE of Sierraville, California

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.