quarry blast · reviewed by a seismologist
M 1.7md
Earthquake near Shasta Lake, CA
No earthquake was likely felt in Shasta Lake in the 24 hours to 11:58 pm PST (07:58 UTC). The last one was M 4.4, 117 km (73 mi) SW, at 3:21 pm PDT on 5 August 2026, estimated intensity II (weak) in town; 122 felt reports to USGS. Every earthquake near Shasta Lake
No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.7 quarry blast was recorded 9 km (6 mi) northeast of Shasta Lake, CA, at 11:28 am PDT on 27 July 2023 (18:28 UTC), less than 1 km deep.
USGS: 9 km NE of Shasta Lake, CA
20 km (12 mi) NNE of Redding, CA · 117 km (73 mi) NNW of Chico, CA
- When
- 11:28 am PDT on 27 July 2023 ()
- Where
- 9 km (6 mi) northeast of Shasta Lake, CA · earthquakes near Shasta Lake
- Magnitude
- M 1.7 (md)
- Depth
- -0.6 km below the surface
- Felt
- no reports yet
- Nearest
- Shasta County, 22 km E
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1203 days ago
Earthquake alerts for Shasta Lake, 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 13 km (8 mi) from the epicentre. In Shasta Lake, 9 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: Shasta Lake 9 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 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
- Magna, Utah 2020 M 5.7 930,000× the energy of this one
- Around the size people start to feel M 3.0 83× the energy of this one
- This earthquake M 1.7 about 11 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 one earthquake of M5 or more within 50 km:
- 5.1 7km NW of Redding, CA · 16 km SW 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 40.7452, -122.3060. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Shasta County, CA | 22 km (14 mi) | E | earthquakes near Shasta County |
| Trinity County, CA | 69 km (43 mi) | W | earthquakes near Trinity County |
| Tehama County, CA | 69 km (43 mi) | S | earthquakes near Tehama County |
| Siskiyou County, CA | 96 km (59 mi) | NNW | earthquakes near Siskiyou County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 1.7 16 km NNE of Shingletown, CA
- 1.8 4 km WNW of Shasta Lake, CA
- 1.8 10 km WSW of Manton, CA
- 2.3 14 km N of Shingletown, CA
- 2.4 11 km WNW of Burney, CA
- 1.7 2 km WNW of Shasta Lake, CA
- 2.9 2 km NW of Shasta Lake, CA
- 1.9 11 km NNE of Shasta Lake, CA
- 1.9 14 km W of Shingletown, CA
- 1.6 14 km SSE of Millville, CA
- 1.7 9 km NE of Shasta Lake, CA
- 1.8 20 km N of Bella Vista, CA
- 1.7 4 km W of Round Mountain, CA
- 1.9 8 km SE of Dunsmuir, CA
- 1.9 3 km S of Shasta Lake, 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.