quarry blast · reviewed by a seismologist
M 1.8md
7km WNW of Chinese Camp, CA
- When
- Magnitude
- M 1.8 (md)
- Depth
- -0.8 km below the surface
- Felt
- no reports yet
- Nearest
- Calaveras County, 33 km N
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2231 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
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.
Where
Epicentre 37.8987, -120.4997. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Calaveras County, CA | 33 km (20 mi) | S of here | earthquakes near Calaveras County |
| Tuolumne County, CA | 49 km (30 mi) | WSW of here | earthquakes near Tuolumne County |
| Stanislaus County, CA | 58 km (36 mi) | NE of here | earthquakes near Stanislaus County |
| Amador County, CA | 62 km (39 mi) | SSE of here | earthquakes near Amador County |
| Mariposa County, CA | 63 km (39 mi) | NW of here | earthquakes near Mariposa County |
| San Joaquin County, CA | 68 km (42 mi) | E of here | earthquakes near San Joaquin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
4 earthquakes have been recorded within 50 km since this one.
- 2.2 9 km NW of Chinese Camp, CA
- 1.9 18km E of Groveland-Big Oak Flat, CA
- 2.3 6km S of Vallecito, CA
- 2.1 11km E of Groveland-Big Oak Flat, 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.