QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

Earthquake near East Quincy, CA

No earthquake was likely felt in East Quincy in the 24 hours to 7:54 pm PST (03:54 UTC). The last one was M 2.3, 6 km (3 mi) N, at 5:11 am PST on 7 November 2026, estimated intensity II (weak) in town. Every earthquake near East Quincy

This page: a magnitude 1.8 earthquake was recorded 9 km (5 mi) east-southeast of East Quincy, CA, at 12:33 am PST on 31 January 2018 (08:33 UTC), 6.8 km deep.

USGS: 1km NNW of Spring Garden, CA

91 km (56 mi) WNW of Reno, NV

12:33 am PST, Jan 31, 2018 · · 6.8 km deep · released about 15 lb of TNT

10 km30 km60 km120 km N Plumas County 9 kmSierra County 44 kmNevada County 69 kmButte County 74 kmYuba County 86 kmLassen County 90 kmPlacer County 95 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
12:33 am PST on 31 January 2018 ()
Where
9 km (5 mi) east-southeast of East Quincy, CA · earthquakes near East Quincy
Magnitude
M 1.8 (md)
Depth
6.8 km below the surface
Felt
no reports yet
Nearest
Plumas County, 9 km NNW
Nearest mapped fault
Mohawk Valley fault, 6 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 3208 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 12 km (7 mi) from the epicentre. In East Quincy, 9 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: East Quincy 9 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 3 earthquakes of M5 or more within 50 km:

  1. 5.9 West of Downieville, California · 49 km SSW of this epicentre
  2. 5.7 2 km NNE of Canyondam, California · 38 km NW of this epicentre
  3. 5.2 3 km N of Blairsden, California · 19 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 39.9153, -120.7993. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Plumas County, CA 9 km (5 mi) NNW earthquakes near Plumas County
Sierra County, CA 44 km (28 mi) SSE earthquakes near Sierra County
Nevada County, CA 69 km (43 mi) S earthquakes near Nevada County
Butte County, CA 74 km (46 mi) WSW earthquakes near Butte County
Yuba County, CA 86 km (53 mi) SSW earthquakes near Yuba County
Lassen County, CA 90 km (56 mi) N earthquakes near Lassen County

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

Aftershocks so far

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

  1. 2.9 6km SW of Almanor, CA
  2. 1.6 20km S of Honey Lake, CA
  3. 1.7 2km NE of Almanor, CA
  4. 1.7 4km WSW of Canyondam, CA
  5. 1.6 7km ESE of East Shore, CA
  6. 2.2 2km NNE of Indian Falls, CA
  7. 2.9 18km SW of Whitehawk, CA
  8. 1.5 6 km SW of Canyondam, California
  9. 2.2 3km SE of Belden, CA
  10. 1.5 3 km SSW of Greenville, California
  11. 2.2 12km WNW of Lake Davis, CA
  12. 1.9 3km W of Delleker, CA
  13. 2.9 3km NNE of Almanor, CA
  14. 2.3 4km NNE of Almanor, CA
  15. 1.8 5km SSW of Cromberg, 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.