QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Big Bear City, CA

No earthquake was likely felt in Big Bear City in the 24 hours to 4:28 am PST (12:28 UTC). The last one was M 1.5, 10 km (6 mi) ESE, at 12:11 pm PST on 3 November 2026, estimated intensity II (weak) in town. Every earthquake near Big Bear City

This page: a magnitude 2.1 earthquake was recorded in Big Bear City, CA, at 1:58 pm PDT on 20 April 2017 (20:58 UTC), less than 1 km deep. 4 people have reported feeling it to USGS.

USGS: 2km SE of Big Bear City, CA

31 km (19 mi) NE of Yucaipa, CA · 147 km (92 mi) E of Los Angeles, CA

1:58 pm PDT, Apr 20, 2017 · · 0.2 km deep · released about 38 lb of TNT

Every earthquake near Big Bear City Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Bernardino County 90 kmRiverside County 96 kmOrange County 108 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
1:58 pm PDT on 20 April 2017 ()
Where
in Big Bear City, CA · earthquakes near Big Bear City
Magnitude
M 2.1 (ml)
Depth
0.2 km below the surface
Felt
4 reports · strongest reported intensity IV
Nearest
San Bernardino County, 90 km NE
Nearest mapped fault
Helendale-South Lockhart fault, 7 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 3467 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 17 km (11 mi) from the epicentre. 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: Big Bear City in town, intensity II · Big Bear Lake 7 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 38 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 5.8 390,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 280,000× the energy of this one
  3. Around the size people start to feel M 3.0 25× the energy of this one
  4. This earthquake M 2.1 about 38 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 4.4 on 2016-01-06 — about 3,000 times the energy of this one.

Before 2016, the USGS record lists 31 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.3 The 1992 Landers, California Earthquake · 37 km E of this epicentre
  2. 6.3 The 1992 Big Bear, California Earthquake · 5 km S of this epicentre
  3. 6.2 3 km SE of San Bernardino, California · 43 km WSW of this epicentre
  4. 6.0 The 1986 North Palm Springs, California Earthquake · 35 km SE of this epicentre
  5. 5.8 3km NE of Yucca Valley, California · 41 km ESE 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 34.2487, -116.8345. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Bernardino County, CA 90 km (56 mi) NE earthquakes near San Bernardino County
Riverside County, CA 96 km (60 mi) SE earthquakes near Riverside County
Orange County, CA 108 km (67 mi) SW earthquakes near Orange County

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

Aftershocks so far

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

  1. 1.6 3km NE of Banning, CA
  2. 1.9 4km SSW of Cabazon, CA
  3. 1.5 1km SSE of Loma Linda, CA
  4. 1.6 3km NNE of Moreno Valley, CA
  5. 1.9 6km SSW of Redlands, CA
  6. 1.5 6km ESE of Cabazon, CA
  7. 1.9 6km ESE of Cabazon, CA
  8. 1.6 8km N of Cabazon, CA
  9. 2.4 2km SE of Loma Linda, CA
  10. 1.9 4km SSW of Cabazon, CA
  11. 3.4 4km SSW of Cabazon, CA
  12. 3.2 5km SSW of Cabazon, CA
  13. 1.5 7km NW of Banning, CA
  14. 1.9 7km NE of Beaumont, CA
  15. 1.6 1km NE of Loma Linda, 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.