QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Fortuna, CA

No earthquake was likely felt in Fortuna in the 24 hours to 10:15 am PST (18:15 UTC). The last one was M 5.0, 123 km (76 mi) W, at 8:56 pm PST on 4 November 2026, estimated intensity II (weak) in town; 145 felt reports to USGS. Every earthquake near Fortuna

This page: a magnitude 1.6 earthquake was recorded 6 km (4 mi) east-northeast of Fortuna, CA, at 7:47 am PDT on 15 July 2019 (14:47 UTC), 21 km deep.

USGS: 6km ENE of Fortuna, CA

7:47 am PDT, Jul 15, 2019 · · 21 km deep · released about 8.4 lb of TNT

10 km30 km60 km120 km N Humboldt County 17 kmTrinity County 83 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
7:47 am PDT on 15 July 2019 ()
Where
6 km (4 mi) east-northeast of Fortuna, CA · earthquakes near Fortuna
Magnitude
M 1.6 (md)
Depth
21 km below the surface
Felt
no reports yet
Nearest
Humboldt County, 17 km ENE
Nearest mapped fault
Little Salmon fault, 4 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 2677 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 Fortuna, 6 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.

Earthquakes near other towns within 30 km: Hydesville, Pine Hills, Humboldt Hill, Rio Dell, Ferndale, Cutten.

How big was it?

This earthquake released about 8.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. This earthquake M 1.6 about 8.4 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

The largest earthquake within 50 km since 2016 was M 5.6 on 2019-06-23 — about 840,000 times the energy of this one.

Before 2016, the USGS record lists 33 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1992 Petrolia, California Earthquake · 34 km SSW of this epicentre
  2. 6.6 32 km SW of Ferndale, California · 47 km SW of this epicentre
  3. 6.5 The 1932 Eureka, California Earthquake · 20 km NW of this epicentre
  4. 6.5 30 km WSW of Ferndale, California · 45 km WSW of this epicentre
  5. 6.4 The 1954 Eureka-Arcata, California Earthquake · 30 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 40.6258, -124.0948. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 17 km (10 mi) ENE earthquakes near Humboldt County
Trinity County, CA 83 km (51 mi) E earthquakes near Trinity 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. 2.0 8km W of Petrolia, CA
  2. 1.9 12km WNW of Petrolia, CA
  3. 2.2 11km W of Petrolia, CA
  4. 2.5 17km W of Petrolia, CA
  5. 1.8 16km W of Petrolia, CA
  6. 2.4 13km SSW of Rio Dell, CA
  7. 2.3 16km WSW of Petrolia, CA
  8. 2.1 16km ENE of Hydesville, CA
  9. 1.8 11km SSW of Ferndale, CA
  10. 1.8 6km SW of Petrolia, CA
  11. 1.6 11km WSW of Ferndale, CA
  12. 2.4 2km WSW of Ferndale, CA
  13. 2.8 16km SSE of Rio Dell, CA
  14. 2.6 7km SE of Pine Hills, CA
  15. 2.8 12km NNE of Petrolia, 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.