QuakeIndex

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 10:26 am PST (18:26 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 1.7 earthquake was recorded 15 km (9 mi) south-southeast of Mammoth Lakes, CA, at 4:09 am PDT on 28 September 2018 (11:09 UTC), 11 km deep. 1 person has reported feeling it to USGS.

USGS: 14km SSE of Mammoth Lakes, CA

4:09 am PDT, Sep 28, 2018 · · 11 km deep · released about 11 lb of TNT

Every earthquake near Mammoth Lakes Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mono County 43 kmMadera County 83 kmMariposa County 90 kmFresno County 109 kmTuolumne County 109 kmEsmeralda County 115 kmMineral County 118 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
4:09 am PDT on 28 September 2018 ()
Where
15 km (9 mi) south-southeast of Mammoth Lakes, CA · earthquakes near Mammoth Lakes
Magnitude
M 1.7 (md)
Depth
11 km below the surface
Felt
1 report · strongest reported intensity IV
Nearest
Mono County, 43 km N
Nearest mapped fault
Hilton Creek fault, 10 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 2967 days ago

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, 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.

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.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 930,000× the energy of this one
  3. Around the size people start to feel M 3.0 83× the energy of this one
  4. 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 38 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 The 1986 Chalfant Valley, California Earthquake · 40 km E of this epicentre
  2. 6.2 9 km SW of Aspen Springs, California · 8 km ESE of this epicentre
  3. 6.1 11 km WNW of Aspen Springs, California · 9 km NE of this epicentre
  4. 6.1 8 km W of Aspen Springs, California · 8 km ENE of this epicentre
  5. 6.1 4 km NNW of Round Valley, California · 27 km ESE 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 37.5283, -118.8952. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mono County, CA 43 km (27 mi) N earthquakes near Mono County
Madera County, CA 83 km (52 mi) WSW earthquakes near Madera County
Mariposa County, CA 90 km (56 mi) W earthquakes near Mariposa County
Fresno County, CA 109 km (68 mi) SW earthquakes near Fresno County
Tuolumne County, CA 109 km (68 mi) WNW earthquakes near Tuolumne County
Esmeralda County, NV 115 km (71 mi) ENE earthquakes near Esmeralda County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

50 earthquakes have been recorded within 50 km since this one.

  1. 3.2 1km SSW of Round Valley, CA
  2. 2.4 12km NNE of Dixon Lane-Meadow Creek, CA
  3. 2.0 13km NNE of Dixon Lane-Meadow Creek, CA
  4. 1.9 18km WSW of Toms Place, CA
  5. 2.0 4km WNW of Mammoth Lakes, CA
  6. 1.6 4km WNW of Mammoth Lakes, CA
  7. 2.1 4km WNW of Mammoth Lakes, CA
  8. 1.9 4km WNW of Mammoth Lakes, CA
  9. 1.6 4km WNW of Mammoth Lakes, CA
  10. 2.2 4km W of Mammoth Lakes, CA
  11. 2.2 4km W of Mammoth Lakes, CA
  12. 2.0 7km ENE of Mammoth Lakes, CA
  13. 1.9 27km SSW of Mammoth Lakes, CA
  14. 1.7 16km WSW of Toms Place, CA
  15. 1.6 15km SW 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.