quarry blast · reviewed by a seismologist
M 2.4md
Earthquake near Johnstonville, CA
No earthquake was likely felt in Johnstonville in the 24 hours to 12:41 am PST (08:41 UTC). The last one was M 2.4, 18 km (11 mi) SE, at 8:04 pm PDT on 4 September 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Johnstonville
No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 2.4 quarry blast was recorded 15 km (9 mi) east of Johnstonville, CA, at 2:45 pm PDT on 15 September 2023 (21:45 UTC), less than 1 km deep.
USGS: 15 km E of Johnstonville, CA
- When
- 2:45 pm PDT on 15 September 2023 ()
- Where
- 15 km (9 mi) east of Johnstonville, CA · earthquakes near Johnstonville
- Magnitude
- M 2.4 (md)
- Depth
- -1.7 km below the surface
- Felt
- no reports yet
- Nearest
- Lassen County, 38 km NNW
- Nearest mapped fault
- Honey Lake fault, 15 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 1152 days ago
Earthquake alerts for Johnstonville, CA
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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 20 km (12 mi) from the epicentre. In Johnstonville, 15 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: Susanville 20 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 100 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 150,000× the energy of this one
- Magna, Utah 2020 M 5.7 110,000× the energy of this one
- Around the size people start to feel M 3.0 9.4× the energy of this one
- This earthquake M 2.4 about 100 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 4.5 on 2016-08-04 — about 1,600 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.6 6 km NNE of Doyle, California · 47 km SE 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 40.4092, -120.4122. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lassen County, CA | 38 km (24 mi) | NNW | earthquakes near Lassen County |
| Plumas County, CA | 58 km (36 mi) | SW | earthquakes near Plumas County |
| Washoe County, NV | 73 km (45 mi) | ENE | earthquakes near Washoe County |
| Sierra County, CA | 93 km (58 mi) | S | earthquakes near Sierra County |
| Butte County, CA | 131 km (81 mi) | SW | earthquakes near Butte County |
| Storey County, NV | 132 km (82 mi) | SE | earthquakes near Storey 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.
- 2.1 14 km N of Susanville, CA
- 1.8 14 km NNW of Susanville, CA
- 2.0 14 km NNW of Susanville, CA
- 1.8 14 km NNW of Susanville, CA
- 2.2 14 km NNW of Susanville, CA
- 2.2 14 km NNW of Susanville, CA
- 2.0 14 km NNW of Susanville, CA
- 1.9 14 km NNW of Susanville, CA
- 2.0 15 km NNW of Susanville, CA
- 2.0 14 km NNW of Susanville, CA
- 2.0 15 km NNW of Susanville, CA
- 2.1 13 km NNW of Susanville, CA
- 2.1 14 km NNW of Susanville, CA
- 1.8 13 km NNW of Susanville, CA
- 2.1 15 km NNW of Susanville, 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.