QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

Earthquake near Willow Creek, CA

No earthquake was likely felt in Willow Creek in the 24 hours to 4:30 am PST (12:30 UTC). The last one was M 5.0, 175 km (109 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 Willow Creek

This page: a magnitude 2.7 earthquake was recorded 14 km (9 mi) east-southeast of Willow Creek, CA, at 11:05 am PDT on 21 June 2018 (18:05 UTC), 28 km deep. 1 person has reported feeling it to USGS.

USGS: 14km ESE of Willow Creek, CA

11:05 am PDT, Jun 21, 2018 · · 28 km deep · released about 380 lb of TNT

Every earthquake near Willow Creek Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Trinity County 41 kmHumboldt County 44 kmDel Norte County 103 kmSiskiyou County 110 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
11:05 am PDT on 21 June 2018 ()
Where
14 km (9 mi) east-southeast of Willow Creek, CA · earthquakes near Willow Creek
Magnitude
M 2.7 (ml)
Depth
28 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Trinity County, 41 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3065 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 Willow Creek, 14 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 380 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 40,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 29,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.5× the energy of this one
  4. This earthquake M 2.7 about 380 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 1,300 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 The 1954 Eureka-Arcata, California Earthquake · 36 km W of this epicentre
  2. 5.8 Near Eureka, California · 46 km WSW of this epicentre
  3. 5.6 15 km SW of Burnt Ranch, California · 24 km SSW of this epicentre
  4. 5.6 26 km NNW of Willow Creek, California · 38 km NW of this epicentre
  5. 5.4 3 km NNW of Burnt Ranch, California · 8 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 40.9015, -123.4753. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 41 km (26 mi) SE earthquakes near Trinity County
Humboldt County, CA 44 km (27 mi) WSW earthquakes near Humboldt County
Del Norte County, CA 103 km (64 mi) NNW earthquakes near Del Norte County
Siskiyou County, CA 110 km (68 mi) NE earthquakes near Siskiyou County
Tehama County, CA 136 km (84 mi) SE earthquakes near Tehama County

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

Aftershocks so far

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

  1. 3.0 27km WNW of Hayfork, CA
  2. 2.7 28km SSE of Somes Bar, CA
  3. 2.4 17km SE of Willow Creek, CA
  4. 2.0 11km WNW of Hayfork, CA
  5. 2.0 11km WNW of Hayfork, CA
  6. 1.6 30km S of Willow Creek, CA
  7. 1.8 16km ESE of Willow Creek, CA
  8. 2.6 21km NW of Weaverville, CA
  9. 2.0 35km W of Hayfork, CA
  10. 2.4 24km NNW of Hayfork, CA
  11. 1.8 17km ESE of Pine Hills, CA
  12. 1.9 8km S of Blue Lake, CA
  13. 2.3 24km E of Hydesville, CA
  14. 3.8 16km ESE of Pine Hills, CA
  15. 2.9 22km NNW of Hayfork, 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.