QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5ml

Earthquake near Home Gardens, CA

No earthquake was likely felt in Home Gardens in the 24 hours to 10:37 am PST (18:37 UTC). The last one was M 1.6, 7 km (4 mi) SSE, at 1:57 pm PST on 6 November 2026, estimated intensity II (weak) in town. Every earthquake near Home Gardens

No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.5 quarry blast was recorded 5 km (3 mi) south-southeast of Home Gardens, CA, at 12:22 pm PDT on 21 August 2020 (19:22 UTC), 2.1 km deep.

USGS: 5km SSE of Home Gardens, CA

7 km (4 mi) ESE of Corona, CA · 87 km (54 mi) ESE of Los Angeles, CA

12:22 pm PDT, Aug 21, 2020 · · 2.1 km deep · released about 5.6 lb of TNT

Every earthquake near Home Gardens Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Orange County 32 kmLos Angeles County 81 kmSan Diego County 113 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
12:22 pm PDT on 21 August 2020 ()
Where
5 km (3 mi) south-southeast of Home Gardens, CA · earthquakes near Home Gardens
Magnitude
M 1.5 (ml)
Depth
2.1 km below the surface
Felt
no reports yet
Nearest
Orange County, 32 km SW
Nearest mapped fault
Elsinore fault, 6 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 2184 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 10 km (6 mi) from the epicentre. In Home Gardens, 5 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: Corona 8 km, intensity II. Estimated for each town centre; each link is that town's own record.

USGS catalogues this as quarry blast, not an earthquake.

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.

  1. Mineral, Virginia 2011 M 5.8 2,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
  3. Around the size people start to feel M 3.0 170× the energy of this one
  4. 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 2018-08-29 — about 20,000 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.7 The 1918 San Jacinto, California Earthquake · 49 km E of this epicentre
  2. 6.2 3 km SE of San Bernardino, California · 35 km NE of this epicentre
  3. 6.0 The 1910 Lake Elsinore, California Earthquake · 18 km SSE of this epicentre
  4. 5.5 The 1990 Upland, California Earthquake · 38 km NNW of this epicentre
  5. 5.4 5km S of Chino Hills, CA · 28 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 33.8430, -117.4938. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Orange County, CA 32 km (20 mi) SW earthquakes near Orange County
Los Angeles County, CA 81 km (50 mi) WNW earthquakes near Los Angeles County
San Diego County, CA 113 km (70 mi) SE earthquakes near San Diego 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. 1.6 1km ESE of Loma Linda, CA
  2. 1.6 11km WNW of Lake Elsinore, CA
  3. 1.6 3km NNW of Brea, CA
  4. 1.6 9km SSE of Chino, CA
  5. 1.6 8km SSE of Home Gardens, CA
  6. 2.6 1km NNW of Loma Linda, CA
  7. 2.5 8km NNW of Rancho Cucamonga, CA
  8. 1.6 4km SSW of Lytle Creek, CA
  9. 1.6 11km NW of Rancho Cucamonga, CA
  10. 1.7 2km NE of Moreno Valley, CA
  11. 3.2 11km NW of Rancho Cucamonga, CA
  12. 1.7 4km SE of Home Gardens, CA
  13. 1.7 11km WNW of Lake Elsinore, CA
  14. 3.3 11km WNW of Lake Elsinore, CA
  15. 1.5 1km N of Redlands, 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.