QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Alturas, CA

No earthquake was likely felt in Alturas in the 24 hours to 2:01 pm PST (22:01 UTC). The last one was M 5.7, 272 km (169 mi) SSE, at 6:29 pm PDT on 13 April 2026, estimated intensity II (weak) in town; 6,515 felt reports to USGS. Every earthquake near Alturas

This page: a magnitude 1.6 earthquake was recorded 50 km (31 mi) east-southeast of Alturas, CA, at 4:32 pm PDT on 23 September 2026 (23:32 UTC), 3.9 km deep.

USGS: 11 km E of Eagleville, California

4:32 pm PDT, Sep 23, 2026 · · 3.9 km deep · released about 6.4 lb of TNT

10 km30 km60 km120 km N Modoc County 68 kmWashoe County 72 kmLassen County 87 km
Distance rings around the epicentre, with the nearest towns at their true direction. Not a shaking map — see the USGS ShakeMap for that.
When
4:32 pm PDT on 23 September 2026 ()
Where
50 km (31 mi) east-southeast of Alturas, CA · earthquakes near Alturas
Magnitude
M 1.6 (ml)
Depth
3.9 km below the surface
Felt
no reports yet
Nearest
Modoc County, 68 km WNW
Nearest mapped fault
Surprise Valley fault, 13 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 48 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 10 km (6 mi) from the epicentre. In Alturas, 50 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 6.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.6 about 6.4 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 one earthquake of M5 or more within 50 km:

  1. 5.2 12 km SE of Eagleville, California · 10 km S 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 41.3350, -119.9801. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Modoc County, CA 68 km (42 mi) WNW earthquakes near Modoc County
Washoe County, NV 72 km (45 mi) SSE earthquakes near Washoe County
Lassen County, CA 87 km (54 mi) SW earthquakes near Lassen County

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

Aftershocks so far

No further earthquakes have been recorded within 50 km since this one.

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.