QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near Mariposa, CA

No earthquake was likely felt in Mariposa in the 24 hours to 8:03 am PST (16:03 UTC). The last one was M 5.7, 222 km (138 mi) NNE, at 6:29 pm PDT on 13 April 2026, estimated intensity II (weak) in town; 6,515 felt reports to USGS. Every earthquake near Mariposa

This page: a magnitude 2.8 earthquake was recorded 9 km (6 mi) south-southwest of Mariposa, CA, at 2:28 pm PDT on 20 September 2025 (21:28 UTC), 21 km deep. 32 people have reported feeling it to USGS.

USGS: 9 km SSW of Mariposa, CA

72 km (45 mi) NNW of Fresno, CA · 43 km (27 mi) ENE of Merced, CA

2:28 pm PDT, Sep 20, 2025 · · 21 km deep · released about 400 lb of TNT

10 km30 km60 km120 km N Mariposa County 20 kmMadera County 32 kmMerced County 68 kmTuolumne County 68 kmFresno County 78 kmStanislaus County 90 kmCalaveras County 99 kmMono County 115 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
2:28 pm PDT on 20 September 2025 ()
Where
9 km (6 mi) south-southwest of Mariposa, CA · earthquakes near Mariposa
Magnitude
M 2.8 (md)
Depth
21 km below the surface
Felt
32 reports · strongest reported intensity III
Nearest
Mariposa County, 20 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 341 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 15 km (9 mi) from the epicentre. In Mariposa, 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: Mariposa 9 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 400 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 38,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 27,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.4× the energy of this one
  4. This earthquake M 2.8 about 400 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 since 1900 lists no earthquake of M5 or more within 50 km.

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 37.4080, -120.0072. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mariposa County, CA 20 km (13 mi) NNE earthquakes near Mariposa County
Madera County, CA 32 km (20 mi) SE earthquakes near Madera County
Merced County, CA 68 km (42 mi) WSW earthquakes near Merced County
Tuolumne County, CA 68 km (42 mi) N earthquakes near Tuolumne County
Fresno County, CA 78 km (49 mi) SSE earthquakes near Fresno County
Stanislaus County, CA 90 km (56 mi) WNW earthquakes near Stanislaus County

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

Aftershocks so far

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

  1. 2.6 5 km WNW of Madera, CA
  2. 1.7 7 km E of Yosemite Lakes, CA
  3. 1.8 11 km S of Yosemite Lakes, CA
  4. 1.7 7 km ENE of Bonadelle Ranchos-Madera Ranchos, CA
  5. 1.8 14 km SSW of Bootjack, CA
  6. 1.9 8 km ESE of Coarsegold, CA
  7. 2.0 8 km ESE of Coarsegold, CA
  8. 2.0 9 km ESE of Coarsegold, CA
  9. 2.0 7 km ENE of Bonadelle Ranchos-Madera Ranchos, CA
  10. 1.8 6 km ENE of Bonadelle Ranchos-Madera Ranchos, CA
  11. 1.7 8 km ESE of Coarsegold, CA
  12. 2.7 8 km NW of Yosemite Lakes, CA
  13. 2.1 11 km S of Yosemite Lakes, CA
  14. 1.9 6 km ENE of Bonadelle Ranchos-Madera Ranchos, CA
  15. 1.7 6 km ENE of Bonadelle Ranchos-Madera Ranchos, 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.