QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Grand Terrace, CA

No earthquake was likely felt in Grand Terrace in the 24 hours to 1:31 pm PST (21:31 UTC). The last one was M 2.1, 6 km (4 mi) E, at 10:40 am PDT on 31 October 2026, estimated intensity II (weak) in town. Every earthquake near Grand Terrace

This page: a magnitude 1.9 earthquake was recorded 3 km (2 mi) northeast of Grand Terrace, CA, at 10:17 pm PDT on 18 September 2019 (05:17 UTC), 18 km deep.

USGS: 3km NE of Grand Terrace, CA

in Colton, CA · 103 km (64 mi) E of Los Angeles, CA

10:17 pm PDT, Sep 18, 2019 · · 18 km deep · released about 21 lb of TNT

Every earthquake near Grand Terrace Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 61 kmLos Angeles County 91 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
10:17 pm PDT on 18 September 2019 ()
Where
3 km (2 mi) northeast of Grand Terrace, CA · earthquakes near Grand Terrace
Magnitude
M 1.9 (ml)
Depth
18 km below the surface
Felt
no reports yet
Nearest
Orange County, 61 km SW
Nearest mapped fault
San Jacinto fault, under 1 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 2611 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 Grand Terrace, 3 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: Loma Linda, Colton, Highgrove, San Bernardino, Rialto, Bloomington.

How big was it?

This earthquake released about 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 730,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 520,000× the energy of this one
  3. Around the size people start to feel M 3.0 46× the energy of this one
  4. This earthquake M 1.9 about 21 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 2018-05-08 — about 7,900 times the energy of this one.

Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1918 San Jacinto, California Earthquake · 43 km SE of this epicentre
  2. 6.3 The 1992 Big Bear, California Earthquake · 46 km ENE of this epicentre
  3. 6.2 3 km SE of San Bernardino, California · 5 km NNE of this epicentre
  4. 6.0 The 1910 Lake Elsinore, California Earthquake · 40 km SSW of this epicentre
  5. 5.6 7km ENE of Running Springs, CA · 31 km NE 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 34.0477, -117.2910. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 61 km (38 mi) SW earthquakes near Orange County
Los Angeles County, CA 91 km (56 mi) W earthquakes near Los Angeles County
San Diego County, CA 123 km (77 mi) SSE earthquakes near San Diego County
Riverside County, CA 124 km (77 mi) ESE earthquakes near Riverside County
San Bernardino County, CA 136 km (84 mi) NE earthquakes near San Bernardino County

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

Aftershocks so far

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

  1. 1.7 2km ESE of Yucaipa, CA
  2. 1.5 7km S of Redlands, CA
  3. 2.4 7km WSW of Calimesa, CA
  4. 1.8 3 km SW of San Bernardino, CA
  5. 2.2 7km NNW of Glen Avon, CA
  6. 1.6 3km W of San Bernardino, CA
  7. 1.6 3 km W of San Bernardino, CA
  8. 1.7 6km ENE of Running Springs, CA
  9. 1.5 3km WSW of San Bernardino, CA
  10. 1.7 2km NNW of Loma Linda, CA
  11. 2.5 6km SE of Big Bear Lake, CA
  12. 1.6 3 km SE of Home Gardens, CA
  13. 1.7 5km SSW of Redlands, CA
  14. 2.4 11km WNW of Lake Elsinore, CA
  15. 2.9 11km WNW of Lake Elsinore, 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.