Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Mammoth Lakes, CA
No earthquake was likely felt in Mammoth Lakes in the 24 hours to 9:26 am PST (17:26 UTC). The last one was M 2.9, 26 km (16 mi) SSE, at 3:54 am PDT on 24 October 2026, estimated intensity II (weak) in town. Every earthquake near Mammoth Lakes
This page: a magnitude 1.6 earthquake was recorded 33 km (21 mi) southeast of Mammoth Lakes, CA, at 10:07 am PST on 18 December 2021 (18:07 UTC), less than 1 km deep.
USGS: 9km NW of Round Valley, CA
- When
- 10:07 am PST on 18 December 2021 ()
- Where
- 33 km (21 mi) southeast of Mammoth Lakes, CA · earthquakes near Mammoth Lakes
- Magnitude
- M 1.6 (md)
- Depth
- -0.4 km below the surface
- Felt
- no reports yet
- Nearest
- Mono County, 53 km NNW
- Nearest mapped fault
- Round Valley fault, 5 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 1790 days ago
Earthquake alerts for Mammoth Lakes, CA
Get a notification in this browser when USGS records an earthquake near Mammoth Lakes, 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 11 km (7 mi) from the epicentre. In Mammoth Lakes, 33 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.
Earthquakes near other towns within 30 km: West Bishop, Dixon Lane-Meadow Creek, Bishop.
How big was it?
This earthquake released about 8.1 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
- Around the size people start to feel M 3.0 120× the energy of this one
- This earthquake M 1.6 about 8.1 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 4.8 on 2016-02-16 — about 53,000 times the energy of this one.
Before 2016, the USGS record lists 39 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 The 1986 Chalfant Valley, California Earthquake · 21 km ENE of this epicentre
- 6.2 9 km SW of Aspen Springs, California · 13 km WNW of this epicentre
- 6.1 11 km WNW of Aspen Springs, California · 20 km NW of this epicentre
- 6.1 8 km W of Aspen Springs, California · 16 km NW of this epicentre
- 6.1 4 km NNW of Round Valley, California · 6 km E 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 37.4675, -118.6688. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mono County, CA | 53 km (33 mi) | NNW | earthquakes near Mono County |
| Esmeralda County, NV | 98 km (61 mi) | ENE | earthquakes near Esmeralda County |
| Madera County, CA | 100 km (62 mi) | WSW | earthquakes near Madera County |
| Mariposa County, CA | 110 km (69 mi) | W | earthquakes near Mariposa County |
| Fresno County, CA | 118 km (73 mi) | SW | earthquakes near Fresno County |
| Mineral County, NV | 119 km (74 mi) | N | earthquakes near Mineral County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
60 earthquakes have been recorded within 50 km since this one.
- 3.3 0km SW of Round Valley, CA
- 1.6 1km SSW of Round Valley, CA
- 3.9 1km SW of Round Valley, CA
- 1.6 16km N of Dixon Lane-Meadow Creek, CA
- 1.9 15km WSW of Toms Place, CA
- 2.4 15km SW of Toms Place, CA
- 1.6 17km E of Toms Place, CA
- 1.8 9km WSW of Round Valley, CA
- 1.6 10km SSW of Mammoth Lakes, CA
- 1.9 17km S of Mammoth Lakes, CA
- 1.7 16km S of Mammoth Lakes, CA
- 1.5 10km W of Toms Place, CA
- 1.6 15km SW of Toms Place, CA
- 2.1 19km ENE of Toms Place, CA
- 1.8 16km WSW of Toms Place, 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.