QuakeIndex

Earthquake · reviewed by a seismologist

M 3.7mw

Earthquake near Redway, CA

No earthquake was likely felt in Redway in the 24 hours to 3:53 am PST (11:53 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 3.7 earthquake was recorded 29 km (18 mi) north-northeast of Redway, CA, at 6:24 pm PDT on 9 October 2020 (01:24 UTC), 29 km deep. 20 people have reported feeling it to USGS.

USGS: 30km NNE of Redway, CA

6:24 pm PDT, Oct 9, 2020 · · 29 km deep · released about 5.9 tons of TNT

Every earthquake near Redway Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 40 kmTrinity County 60 kmMendocino County 108 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
6:24 pm PDT on 9 October 2020 ()
Where
29 km (18 mi) north-northeast of Redway, CA · earthquakes near Redway
Magnitude
M 3.7 (mw)
Depth
29 km below the surface
Felt
20 reports · strongest reported intensity IV
Measured shaking
intensity V (ShakeMap)
Nearest
Humboldt County, 40 km NNW
Nearest mapped fault
Little Salmon 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 2154 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 72 km (45 mi) from the epicentre. In Redway, 29 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: Redway 29 km, intensity II · Rio Dell 34 km, intensity II · Fortuna 44 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 5.9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 29,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,300× the energy of this one
  3. Magna, Utah 2020 M 5.7 900× the energy of this one
  4. This earthquake M 3.7 about 5.9 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 12× more

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 2016-07-21 — about 42 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1992 Petrolia, California Earthquake · 42 km W of this epicentre
  2. 6.0 Near Rio Dell, California · 42 km WNW of this epicentre
  3. 6.0 30 km SSW of Scotia, California · 49 km WSW of this epicentre
  4. 5.6 15 km SW of Burnt Ranch, California · 39 km NNE of this epicentre
  5. 5.5 7 km ESE of Shelter Cove, California · 48 km SSW 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 40.3762, -123.7327. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 40 km (25 mi) NNW earthquakes near Humboldt County
Trinity County, CA 60 km (37 mi) ENE earthquakes near Trinity County
Mendocino County, CA 108 km (67 mi) SSE earthquakes near Mendocino County
Glenn County, CA 142 km (88 mi) SE earthquakes near Glenn 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. 1.8 12km SE of Petrolia, CA
  2. 2.2 19km SSE of Rio Dell, CA
  3. 2.3 1km N of Redway, CA
  4. 2.1 16km E of Petrolia, CA
  5. 4.0 20km ENE of Redway, CA
  6. 1.9 10km S of Petrolia, CA
  7. 1.8 35km S of Willow Creek, CA
  8. 2.3 26km S of Hayfork, CA
  9. 1.9 29km NE of Redway, CA
  10. 2.5 14km SE of Petrolia, CA
  11. 1.8 27km SSE of Blue Lake, CA
  12. 2.0 19km NE of Redway, CA
  13. 2.2 8km SSE of Ferndale, CA
  14. 2.1 11km SSE of Redway, CA
  15. 2.4 34km E of Hydesville, 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.