Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Mammoth Lakes, CA
No earthquake was likely felt in Mammoth Lakes in the 24 hours to 2:47 pm PST (22:47 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 1.7 earthquake was recorded 35 km (22 mi) south-southeast of Mammoth Lakes, CA, at 6:13 pm PST on 9 February 2021 (02:13 UTC), 9.8 km deep.
USGS: 17km WSW of Round Valley, CA
- When
- 6:13 pm PST on 9 February 2021 ()
- Where
- 35 km (22 mi) south-southeast of Mammoth Lakes, CA · earthquakes near Mammoth Lakes
- Magnitude
- M 1.7 (md)
- Depth
- 9.8 km below the surface
- Felt
- no reports yet
- Nearest
- Mono County, 61 km N
- Nearest mapped fault
- Hilton Creek 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 2101 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 7 km (4 mi) from the epicentre. In Mammoth Lakes, 35 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.
How big was it?
This earthquake released about 9.6 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 1,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
- Around the size people start to feel M 3.0 99× the energy of this one
- This earthquake M 1.7 about 9.6 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 45,000 times the energy of this one.
Before 2016, the USGS record lists 37 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 The 1986 Chalfant Valley, California Earthquake · 35 km ENE of this epicentre
- 6.2 9 km SW of Aspen Springs, California · 15 km N of this epicentre
- 6.1 11 km WNW of Aspen Springs, California · 25 km N of this epicentre
- 6.1 8 km W of Aspen Springs, California · 20 km N of this epicentre
- 6.1 4 km NNW of Round Valley, California · 19 km ENE 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 37.3723, -118.7867. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mono County, CA | 61 km (38 mi) | N | earthquakes near Mono County |
| Madera County, CA | 87 km (54 mi) | WSW | earthquakes near Madera County |
| Mariposa County, CA | 102 km (63 mi) | WNW | earthquakes near Mariposa County |
| Fresno County, CA | 103 km (64 mi) | SW | earthquakes near Fresno County |
| Esmeralda County, NV | 111 km (69 mi) | ENE | earthquakes near Esmeralda County |
| Tuolumne County, CA | 126 km (78 mi) | NW | earthquakes near Tuolumne County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 2.5 9km WSW of Toms Place, CA
- 1.6 14km SW of Toms Place, CA
- 1.7 14km SW of Toms Place, CA
- 1.8 14km ESE of Mammoth Lakes, CA
- 2.2 17km WSW of Toms Place, CA
- 1.8 4km ENE of Round Valley, CA
- 2.3 13km W of Toms Place, CA
- 1.8 16km SW of Toms Place, CA
- 1.6 13km W of Toms Place, CA
- 1.9 10km WSW of Toms Place, CA
- 2.6 16km WSW of Toms Place, CA
- 1.6 5km NNE of Wilkerson, CA
- 1.6 2km E of Round Valley, CA
- 1.9 4km ENE of Round Valley, CA
- 2.0 3km NNE of Wilkerson, 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.