quarry blast · reviewed by a seismologist
M 1.8ml
Earthquake near Bonita, CA
No earthquake was likely felt in Bonita in the 24 hours to 4:44 am PST (12:44 UTC). The last one was M 4.9, 175 km (109 mi) E, at 10:27 am PST on 3 November 2026, estimated intensity II (weak) in town; 321 felt reports to USGS. Every earthquake near Bonita
No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.8 quarry blast was recorded 7 km (4 mi) east-southeast of Bonita, CA, at 3:30 pm PST on 16 February 2021 (23:30 UTC), less than 1 km deep. 2 people have reported feeling it to USGS.
USGS: 7km ESE of Bonita, CA
in Chula Vista, CA
- When
- 3:30 pm PST on 16 February 2021 ()
- Where
- 7 km (4 mi) east-southeast of Bonita, CA · earthquakes near Bonita
- Magnitude
- M 1.8 (ml)
- Depth
- -0.4 km below the surface
- Felt
- 2 reports · strongest reported intensity III
- Nearest
- San Diego County, 47 km NNE
- Nearest mapped fault
- Newport-Inglewood-Rose Canyon fault, 14 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 2094 days ago
Earthquake alerts for Bonita, CA
Get a notification in this browser when USGS records an earthquake near Bonita, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 14 km (9 mi) from the epicentre. In Bonita, 7 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: La Presa, Chula Vista, Jamul, Spring Valley, Rancho San Diego, National City.
USGS catalogues this as quarry blast, not an earthquake.
How big was it?
This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
- Magna, Utah 2020 M 5.7 710,000× the energy of this one
- Around the size people start to feel M 3.0 63× the energy of this one
- This earthquake M 1.8 about 15 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 since 1900 lists no earthquake of M5 or more within 50 km.
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 32.6280, -116.9663. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Diego County, CA | 47 km (29 mi) | NNE | earthquakes near San Diego County |
| Orange County, CA | 139 km (86 mi) | NNW | earthquakes near Orange County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
43 earthquakes have been recorded within 50 km since this one.
- 2.6 10km SE of Tijuana, B.C., MX
- 1.5 5km ESE of Chula Vista, CA
- 1.6 5km NE of San Ysidro, CA
- 1.7 20km NNE of Primo Tapia, B.C., MX
- 1.6 6km NNW of Lakeside, CA
- 1.7 18km WSW of La Jolla, CA
- 1.6 5km NE of Rancho San Diego, CA
- 1.7 21km NNE of Primo Tapia, B.C., MX
- 1.6 21km NNE of Primo Tapia, B.C., MX
- 1.6 4km NNE of San Ysidro, CA
- 1.6 3km NNE of San Ysidro, CA
- 1.6 6km NNW of Lakeside, CA
- 2.0 13km NW of Rosarito, B.C., MX
- 1.6 3km ENE of Rancho San Diego, CA
- 1.6 5km SE of Chula Vista, 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.