Earthquake · reviewed by a seismologist
M 1.9ml
Earthquake near Alta Sierra, CA
No earthquake was likely felt in Alta Sierra in the 24 hours to 6:52 am PST (14:52 UTC). The last one was M 3.1, 14 km (9 mi) ESE, at 2:37 am PDT on 6 October 2026, estimated intensity III (weak) in town; 30 felt reports to USGS. Every earthquake near Alta Sierra
This page: a magnitude 1.9 earthquake was recorded 42 km (26 mi) north-northeast of Alta Sierra, CA, at 8:31 pm PDT on 19 September 2017 (03:31 UTC), 5.0 km deep.
USGS: 34km W of Coso Junction, CA
- When
- 8:31 pm PDT on 19 September 2017 ()
- Where
- 42 km (26 mi) north-northeast of Alta Sierra, CA · earthquakes near Alta Sierra
- Magnitude
- M 1.9 (ml)
- Depth
- 5.0 km below the surface
- Felt
- no reports yet
- Nearest
- Tulare County, 44 km WNW
- Nearest mapped fault
- Kern Canyon fault, 11 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 3304 days ago
Earthquake alerts for Alta Sierra, CA
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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 13 km (8 mi) from the epicentre. In Alta Sierra, 42 km away, the estimate is intensity I (not felt). 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.
How big was it?
This earthquake released about 19 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 810,000× the energy of this one
- Magna, Utah 2020 M 5.7 580,000× the energy of this one
- Around the size people start to feel M 3.0 51× the energy of this one
- This earthquake M 1.9 about 19 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 4 earthquakes of M5 or more within 50 km:
- 5.2 7km ESE of Coso Junction, CA · 41 km E of this epicentre
- 5.0 5 km S of Springville, California · 45 km W of this epicentre
- 5.0 22km WNW of Inyokern, CA · 48 km SSE of this epicentre
- 5.0 23km SSW of Little Lake, CA · 43 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 36.0625, -118.3312. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Tulare County, CA | 44 km (28 mi) | WNW | earthquakes near Tulare County |
| Kern County, CA | 87 km (54 mi) | SSW | earthquakes near Kern County |
| Inyo County, CA | 100 km (62 mi) | NE | earthquakes near Inyo County |
| Fresno County, CA | 142 km (88 mi) | WNW | earthquakes near Fresno County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
52 earthquakes have been recorded within 50 km since this one.
- 1.6 8km ENE of Coso Junction, CA
- 1.5 25km WNW of Inyokern, CA
- 1.5 34km W of Coso Junction, CA
- 2.1 5km NE of Coso Junction, CA
- 2.5 11km E of Coso Junction, CA
- 2.7 32km ESE of Porterville, CA
- 2.4 11km SE of Olancha, CA
- 1.6 32km NNE of Kernville, CA
- 1.6 11km S of Little Lake, CA
- 1.9 11km S of Little Lake, CA
- 1.6 11km S of Little Lake, CA
- 1.9 32km NNE of Kernville, CA
- 1.6 9km SW of Little Lake, CA
- 1.7 12km NE of Little Lake, CA
- 1.9 28km N of Kernville, 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.