QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Fortuna, CA

No earthquake was likely felt in Fortuna in the 24 hours to 9:34 pm PST (05:34 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 1.7 earthquake was recorded 39 km (25 mi) south of Fortuna, CA, at 2:17 pm PDT on 18 April 2017 (21:17 UTC), 11 km deep.

USGS: 23 km WSW of Weott, California

2:17 pm PDT, Apr 18, 2017 · · 11 km deep · released about 11 lb of TNT

Every earthquake near Fortuna Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 56 kmTrinity County 100 kmMendocino 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
2:17 pm PDT on 18 April 2017 ()
Where
39 km (25 mi) south of Fortuna, CA · earthquakes near Fortuna
Magnitude
M 1.7 (md)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Humboldt County, 56 km NNE
Nearest mapped fault
San Andreas fault, 10 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 3493 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 5 km (3 mi) from the epicentre. In Fortuna, 39 km away, the estimate is intensity I (not felt). 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: Rio Dell.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 89× the energy of this one
  4. This earthquake M 1.7 about 11 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 4.4 on 2016-01-02 — about 13,000 times the energy of this one.

Before 2016, the USGS record lists 30 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1992 Petrolia, California Earthquake · 11 km NNW of this epicentre
  2. 6.6 32 km SW of Ferndale, California · 36 km WNW of this epicentre
  3. 6.5 30 km WSW of Ferndale, California · 39 km WNW of this epicentre
  4. 6.0 Near Rio Dell, California · 29 km N of this epicentre
  5. 6.0 53 km SW of Ferndale, California · 46 km W 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 40.2435, -124.1743. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 56 km (35 mi) NNE earthquakes near Humboldt County
Trinity County, CA 100 km (62 mi) ENE earthquakes near Trinity County
Mendocino County, CA 110 km (68 mi) SE earthquakes near Mendocino County

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

Aftershocks so far

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

  1. 1.9 30 km SW of Scotia, California
  2. 2.6 38 km SW of Ferndale, California
  3. 2.2 32 km SSW of Ferndale, California
  4. 1.7 8 km E of Redcrest, California
  5. 2.4 41 km SW of Ferndale, California
  6. 2.0 2 km N of Redway, California
  7. 1.6 19 km WSW of Scotia, California
  8. 2.4 43 km SW of Ferndale, California
  9. 2.0 26 km SSW of Scotia, California
  10. 2.2 28 km SW of Scotia, California
  11. 1.9 23 km WSW of Weott, California
  12. 2.6 38 km SW of Ferndale, California
  13. 1.5 8 km W of Rio Dell, California
  14. 2.3 8 km W of Rio Dell, California
  15. 1.5 11 km SW of Scotia, California

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.