Earthquake · reviewed by a seismologist
M 1.5ml
Earthquake near Rialto, CA
No earthquake was likely felt in Rialto in the 24 hours to 8:53 am PST (16:53 UTC). The last one was M 2.1, 14 km (9 mi) SE, at 10:40 am PDT on 31 October 2026, estimated intensity II (weak) in town. Every earthquake near Rialto
This page: a magnitude 1.5 earthquake was recorded 3 km (2 mi) east-northeast of Rialto, CA, at 9:54 pm PST on 31 December 2017 (05:54 UTC), 12 km deep.
USGS: 3km ENE of Rialto, CA
5 km (3 mi) WSW of San Bernardino, CA · in Rialto, CA
- When
- 9:54 pm PST on 31 December 2017 ()
- Where
- 3 km (2 mi) east-northeast of Rialto, CA · earthquakes near Rialto
- Magnitude
- M 1.5 (ml)
- Depth
- 12 km below the surface
- Felt
- no reports yet
- Nearest
- Orange County, 63 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 3230 days ago
Earthquake alerts for Rialto, CA
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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 Rialto, 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: Muscoy, San Bernardino, Colton, Bloomington, Fontana, Grand Terrace.
How big was it?
This earthquake released about 5.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,700,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
- Around the size people start to feel M 3.0 170× the energy of this one
- This earthquake M 1.5 about 5.6 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 4.4 on 2016-01-06 — about 21,000 times the energy of this one.
Before 2016, the USGS record lists 20 earthquakes of M5 or more within 50 km; the five largest:
- 6.3 The 1992 Big Bear, California Earthquake · 49 km ENE of this epicentre
- 6.2 3 km SE of San Bernardino, California · 8 km ESE of this epicentre
- 6.0 The 1910 Lake Elsinore, California Earthquake · 46 km S of this epicentre
- 5.6 7km ENE of Running Springs, CA · 31 km ENE of this epicentre
- 5.5 The 1990 Upland, California Earthquake · 33 km W 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 34.1143, -117.3438. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Orange County, CA | 63 km (39 mi) | SW | earthquakes near Orange County |
| Los Angeles County, CA | 85 km (53 mi) | W | earthquakes near Los Angeles County |
| San Bernardino County, CA | 135 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
51 earthquakes have been recorded within 50 km since this one.
- 1.7 3km SE of Mentone, CA
- 1.8 9km NNW of Big Bear Lake, CA
- 1.5 3km SE of Mentone, CA
- 1.5 5km SSE of Home Gardens, CA
- 1.5 1km NE of Lytle Creek, CA
- 1.5 2km WSW of Devore, CA
- 2.6 3km ESE of Loma Linda, CA
- 1.5 3km ESE of Loma Linda, CA
- 1.7 6km SSW of Redlands, CA
- 1.5 1km NE of Calimesa, CA
- 3.3 3km S of Mentone, CA
- 1.7 4km W of Pomona, CA
- 2.1 5km SSE of Mentone, CA
- 2.2 10km E of Running Springs, CA
- 2.2 6km NNE of Fontana, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.