QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Big Bear City, CA

No earthquake was likely felt in Big Bear City in the 24 hours to 8:38 am PST (16:38 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 1.7 earthquake was recorded 9 km (6 mi) east-southeast of Big Bear City, CA, at 12:23 pm PST on 1 December 2017 (20:23 UTC), 6.5 km deep.

USGS: 9km ESE of Big Bear City, CA

67 km (42 mi) ENE of Riverside, CA · 34 km (21 mi) NE of Yucaipa, CA

12:23 pm PST, Dec 1, 2017 · · 6.5 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N San Bernardino County 88 kmRiverside County 89 kmOrange County 112 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
12:23 pm PST on 1 December 2017 ()
Where
9 km (6 mi) east-southeast of Big Bear City, CA · earthquakes near Big Bear City
Magnitude
M 1.7 (ml)
Depth
6.5 km below the surface
Felt
no reports yet
Nearest
San Bernardino County, 88 km NE
Nearest mapped fault
Helendale-South Lockhart 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 3268 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 11 km (7 mi) from the epicentre. In Big Bear City, 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: Big Bear City 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 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 970,000× the energy of this one
  3. Around the size people start to feel M 3.0 86× the energy of this one
  4. This earthquake M 1.7 about 11 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 10,000 times the energy of this one.

Before 2016, the USGS record lists 36 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.3 The 1992 Landers, California Earthquake · 29 km E of this epicentre
  2. 6.3 The 1992 Big Bear, California Earthquake · 7 km WSW of this epicentre
  3. 6.2 3 km SE of San Bernardino, California · 49 km WSW of this epicentre
  4. 6.1 The 1992 Joshua Tree, California Earthquake · 50 km SE of this epicentre
  5. 6.0 The 1948 Desert Hot Springs, California Earthquake · 47 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 34.2247, -116.7548. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Bernardino County, CA 88 km (55 mi) NE earthquakes near San Bernardino County
Riverside County, CA 89 km (55 mi) SE earthquakes near Riverside County
Orange County, CA 112 km (70 mi) WSW earthquakes near Orange County

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

Aftershocks so far

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

  1. 1.5 9km N of Big Bear City, CA
  2. 2.2 8km NE of Cabazon, CA
  3. 1.8 22km N of Yucca Valley, CA
  4. 2.1 5km SSE of Mentone, CA
  5. 2.2 10km E of Running Springs, CA
  6. 1.6 3km E of Yucaipa, CA
  7. 1.5 10km E of Yucaipa, CA
  8. 2.9 5km W of Morongo Valley, CA
  9. 1.8 3km WSW of Big Bear City, CA
  10. 2.0 19km NE of Big Bear City, CA
  11. 1.9 9km NNE of Beaumont, CA
  12. 1.6 7km NNE of Beaumont, CA
  13. 1.8 11km NE of Running Springs, CA
  14. 1.6 11km SE of Lucerne Valley, CA
  15. 1.8 14km W of Morongo Valley, 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.