QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5ml

Earthquake near Upland, CA

No earthquake was likely felt in Upland in the 24 hours to 5:01 am PST (13:01 UTC). The last one was M 1.7, 10 km (6 mi) SSE, at 2:48 pm PDT on 9 October 2026, estimated intensity II (weak) in town. Every earthquake near Upland

This page: a magnitude 2.5 earthquake was recorded 3 km (2 mi) east-northeast of Upland, CA, at 7:30 am PDT on 23 March 2018 (14:30 UTC), 14 km deep. 16 people have reported feeling it to USGS.

USGS: 3km ENE of Upland, CA

in Upland, CA · 73 km (46 mi) E of Los Angeles, CA

7:30 am PDT, Mar 23, 2018 · · 14 km deep · released about 160 lb of TNT

Every earthquake near Upland Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 50 kmLos Angeles County 60 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
7:30 am PDT on 23 March 2018 ()
Where
3 km (2 mi) east-northeast of Upland, CA · earthquakes near Upland
Magnitude
M 2.5 (ml)
Depth
14 km below the surface
Felt
16 reports · strongest reported intensity III
Nearest
Orange County, 50 km SSW
Nearest mapped fault
Red Hill-Etiwanda Avenue fault, 2 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 3030 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 18 km (11 mi) from the epicentre. In Upland, 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.

Likely felt in: Upland 3 km, intensity II · Rancho Cucamonga 3 km, intensity II · Ontario 5 km, intensity II · Montclair 7 km, intensity II · Claremont 9 km, intensity II · Chino 12 km, intensity II · Pomona 13 km, intensity II · La Verne 13 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 160 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 92,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 65,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.8× the energy of this one
  4. This earthquake M 2.5 about 160 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 14 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 3 km SE of San Bernardino, California · 34 km E of this epicentre
  2. 6.0 The 1910 Lake Elsinore, California Earthquake · 50 km SSE of this epicentre
  3. 5.9 The 1987 Whittier Narrows, California Earthquake · 42 km W of this epicentre
  4. 5.8 The 1991 Sierra Madre, California Earthquake · 39 km WNW of this epicentre
  5. 5.5 The 1990 Upland, California Earthquake · 8 km WNW 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 34.1068, -117.6228. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 50 km (31 mi) SSW earthquakes near Orange County
Los Angeles County, CA 60 km (37 mi) W earthquakes near Los Angeles County

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

Aftershocks so far

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

  1. 2.5 6km SW of Lytle Creek, CA
  2. 2.0 4km WNW of Muscoy, CA
  3. 1.7 6km NNW of Fontana, CA
  4. 2.2 8km ENE of Moreno Valley, CA
  5. 1.6 8km ENE of Moreno Valley, CA
  6. 2.7 2km ENE of La Habra, CA
  7. 2.0 5km ENE of Ontario, CA
  8. 2.2 5km SE of Loma Linda, CA
  9. 1.9 6km N of Moreno Valley, CA
  10. 1.7 8km S of Hesperia, CA
  11. 1.9 4km SE of Home Gardens, CA
  12. 1.6 8km ESE of North Tustin, CA
  13. 2.1 1km WNW of Pomona, CA
  14. 1.8 6km S of Redlands, CA
  15. 1.6 12km NE of Trabuco Canyon, 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.