Earthquake · reviewed by a seismologist
M 4.4mw
Earthquake near Humboldt Hill, CA
No earthquake was likely felt in Humboldt Hill in the 24 hours to 1:50 am PST (09:50 UTC). The last one was M 5.0, 123 km (76 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 Humboldt Hill
This page: a magnitude 4.4 earthquake was recorded 17 km (11 mi) west of Humboldt Hill, CA, at 9:24 am PDT on 22 March 2018 (16:24 UTC), 25 km deep. 1,236 people have reported feeling it to USGS.
USGS: 17km W of Humboldt Hill, CA
- When
- 9:24 am PDT on 22 March 2018 ()
- Where
- 17 km (11 mi) west of Humboldt Hill, CA · earthquakes near Humboldt Hill
- Magnitude
- M 4.4 (mw)
- Depth
- 25 km below the surface
- Felt
- 1,236 reports · strongest reported intensity V
- Measured shaking
- intensity V (ShakeMap)
- USGS impact alert
- green
- Tsunami
- USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
- Nearest
- Humboldt County, 39 km E
- Nearest mapped fault
- Little Salmon 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 2426 days ago
Earthquake alerts for Humboldt Hill, CA
Get a notification in this browser when USGS records an earthquake near Humboldt Hill, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
At this magnitude and depth, people at rest would likely notice it out to about 129 km (80 mi) from the epicentre. In Humboldt Hill, 17 km away, the estimate is intensity III (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: Humboldt Hill 17 km, intensity III · Eureka 20 km, intensity III · Ferndale 22 km, intensity III · Fortuna 26 km, intensity III · Bayside 29 km, intensity III · McKinleyville 33 km, intensity III · Rio Dell 37 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 64 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.4 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 2,600× the energy of this one
- Mineral, Virginia 2011 M 5.8 120× the energy of this one
- Magna, Utah 2020 M 5.7 83× the energy of this one
- This earthquake M 4.4 about 64 tons of TNT
- Around the size people start to feel M 3.0 this one released 130× 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 3.8 times the energy of this one.
Before 2016, the USGS record lists 32 earthquakes of M5 or more within 50 km; the five largest:
- 7.2 The 1980 Eureka, California Earthquake · 42 km NNE of this epicentre
- 7.2 The 1992 Petrolia, California Earthquake · 48 km SSE of this epicentre
- 6.6 32 km SW of Ferndale, California · 43 km SSW of this epicentre
- 6.5 The 1932 Eureka, California Earthquake · 9 km ESE of this epicentre
- 6.5 30 km WSW of Ferndale, California · 39 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 40.7513, -124.3892. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Humboldt County, CA | 39 km (24 mi) | E | earthquakes near Humboldt County |
| Trinity County, CA | 108 km (67 mi) | E | earthquakes near Trinity County |
| Del Norte County, CA | 116 km (72 mi) | NNE | earthquakes near Del Norte County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
47 earthquakes have been recorded within 50 km since this one.
- 2.8 28km NW of Ferndale, CA
- 1.6 16km NNW of Petrolia, CA
- 2.0 16km WNW of Petrolia, CA
- 1.8 12km SSW of Ferndale, CA
- 1.7 14km WNW of Petrolia, CA
- 1.8 15km SE of Blue Lake, CA
- 1.7 12km S of Rio Dell, CA
- 1.7 2km SSE of Hydesville, CA
- 2.3 6km SSE of Pine Hills, CA
- 2.0 13km W of Ferndale, CA
- 1.7 10km WSW of Petrolia, CA
- 2.7 5km WNW of Arcata, CA
- 2.5 34km WNW of Petrolia, CA
- 1.7 21km NW of Petrolia, CA
- 2.7 35km WNW of Ferndale, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.