QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

Earthquake near Eureka, CA

No earthquake was likely felt in Eureka in the 24 hours to 3:14 am PST (11:14 UTC). The last one was M 5.0, 128 km (79 mi) WSW, at 8:56 pm PST on 4 November 2026, estimated intensity II (weak) in town; 145 felt reports to USGS. Every earthquake near Eureka

This page: a magnitude 2.6 earthquake was recorded 41 km (26 mi) east-southeast of Eureka, CA, at 11:51 pm PDT on 9 April 2018 (06:51 UTC), 26 km deep. 1 person has reported feeling it to USGS.

USGS: 32km SSW of Willow Creek, CA

11:51 pm PDT, Apr 9, 2018 · · 26 km deep · released about 220 lb of TNT

Every earthquake near Eureka Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 19 kmTrinity County 51 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
11:51 pm PDT on 9 April 2018 ()
Where
41 km (26 mi) east-southeast of Eureka, CA · earthquakes near Eureka
Magnitude
M 2.6 (md)
Depth
26 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Humboldt County, 19 km WNW
Nearest mapped fault
Bald Mountain-Big Lagoon fault, 14 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 3129 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 it was probably too small to be felt, even directly above it. In Eureka, 41 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 220 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 68,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 48,000× the energy of this one
  3. Around the size people start to feel M 3.0 4.3× the energy of this one
  4. This earthquake M 2.6 about 220 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 4.8 on 2016-07-21 — about 2,200 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 The 1932 Eureka, California Earthquake · 49 km W of this epicentre
  2. 6.4 The 1954 Eureka-Arcata, California Earthquake · 26 km NW of this epicentre
  3. 6.0 Near Rio Dell, California · 45 km WSW of this epicentre
  4. 5.8 Near Eureka, California · 29 km WNW of this epicentre
  5. 5.6 15 km SW of Burnt Ranch, California · 10 km NE 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 40.6582, -123.7140. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 19 km (12 mi) WNW earthquakes near Humboldt County
Trinity County, CA 51 km (31 mi) E earthquakes near Trinity County
Siskiyou County, CA 143 km (89 mi) NE earthquakes near Siskiyou County
Glenn County, CA 162 km (101 mi) SE earthquakes near Glenn County

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

Aftershocks so far

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

  1. 2.5 29km W of Hayfork, CA
  2. 2.6 7km SE of Pine Hills, CA
  3. 2.5 25km W of Hayfork, CA
  4. 2.2 8km SSE of Ferndale, CA
  5. 2.7 8km SSE of Ferndale, CA
  6. 1.6 23km NNE of Redway, CA
  7. 2.1 27km W of Hayfork, CA
  8. 2.2 27km E of Rio Dell, CA
  9. 2.2 6km NNE of Hydesville, CA
  10. 2.1 6km NNE of Hydesville, CA
  11. 2.7 6km NNE of Hydesville, CA
  12. 1.9 24km SSE of Blue Lake, CA
  13. 2.1 13km WSW of Hayfork, CA
  14. 1.7 13km ESE of Hydesville, CA
  15. 1.9 21km SSE of Rio Dell, 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.