QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Redway, CA

No earthquake was likely felt in Redway in the 24 hours to 10:48 am PST (18:48 UTC). The last one was M 5.0, 153 km (95 mi) WNW, at 8:56 pm PST on 4 November 2026, estimated intensity II (weak) in town; 145 felt reports to USGS. Every earthquake near Redway

This page: a magnitude 2.1 earthquake was recorded 12 km (8 mi) east-southeast of Redway, CA, at 4:23 pm PDT on 21 April 2024 (23:23 UTC), 22 km deep. 1 person has reported feeling it to USGS.

USGS: 12 km ESE of Redway, CA

4:23 pm PDT, Apr 21, 2024 · · 22 km deep · released about 37 lb of TNT

10 km30 km60 km120 km N Humboldt County 73 kmMendocino County 75 kmTrinity County 80 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
4:23 pm PDT on 21 April 2024 ()
Where
12 km (8 mi) east-southeast of Redway, CA · earthquakes near Redway
Magnitude
M 2.1 (md)
Depth
22 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Humboldt County, 73 km NNW
Nearest mapped fault
Bartlett Springs fault system, 11 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 930 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Redway, 12 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 37 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 410,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 290,000× the energy of this one
  3. Around the size people start to feel M 3.0 26× the energy of this one
  4. This earthquake M 2.1 about 37 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 5.3 on 2023-01-01 — about 86,000 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.9 9 km S of Leggett, California · 33 km S of this epicentre
  2. 5.5 7 km ESE of Shelter Cove, California · 28 km WSW of this epicentre
  3. 5.3 18 km SSW of Scotia, California · 49 km NW 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 40.0768, -123.6907. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 73 km (45 mi) NNW earthquakes near Humboldt County
Mendocino County, CA 75 km (46 mi) SSE earthquakes near Mendocino County
Trinity County, CA 80 km (50 mi) NE earthquakes near Trinity County
Glenn County, CA 122 km (76 mi) ESE earthquakes near Glenn County
Lake County, CA 135 km (84 mi) SE earthquakes near Lake County

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

Aftershocks so far

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

  1. 1.6 16 km N of Covelo, CA
  2. 2.5 22 km S of Rio Dell, CA
  3. 2.2 22 km ESE of Petrolia, CA
  4. 1.7 19 km NNW of Laytonville, CA
  5. 1.5 2 km NNW of Redway, CA
  6. 1.6 3 km SE of Redway, CA
  7. 1.7 10 km SE of Rio Dell, CA
  8. 1.6 37 km ESE of Hydesville, CA
  9. 1.9 6 km W of Laytonville, CA
  10. 1.9 6 km W of Laytonville, CA
  11. 1.6 16 km SE of Petrolia, CA
  12. 1.8 5 km WSW of Laytonville, CA
  13. 1.5 23 km NNE of Redway, CA
  14. 1.9 5 km WSW of Laytonville, CA
  15. 1.8 5 km WSW of Laytonville, 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.