Reviewed by USGSCalifornia21y ago
M2.5 earthquake 40 km WSW of Ferndale, California
Saturday, December 17, 2005, 19:16:51 UTC · 40.507°N, 124.728°W
A magnitude 2.5 earthquake struck 40 km WSW of Ferndale, California on Saturday, December 17, 2005, 19:16:51 UTC, at a depth of 24.7 km (shallow).
- Magnitude
- 2.5
- Minor · md
- Depth
- 25 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
91 kg of TNT
That is about 1/165,707 of the Hiroshima bomb. A magnitude 5.0 releases about 5,248 times more energy.
Tectonic setting
11 km
from the nearest mapped plate boundary, between the Juan de Fuca and North American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
25 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 50 km
USGS lists 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.3 on December 23, 2005. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 2.731 km SW of Scotia, California20y ago · 41 km SE of this epicenter
- 2.512 km SW of Scotia, California20y ago · 46 km E of this epicenter
- 2.634 km WSW of Ferndale, California21y ago · 15 km SE of this epicenter
- 4.385 km W of Ferndale, California21y ago · 45 km W of this epicenter
- 3.279 km WSW of Ferndale, California21y ago · 40 km W of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 190 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.4123 km W of Big Lagoon, CaliforniaJanuary 31, 1922 · 106 km NW of this epicenter
- 7.2The 1992 Petrolia, California EarthquakeApril 25, 1992 · 46 km SE of this epicenter
- 7.2The 1980 Eureka, California EarthquakeNovember 8, 1980 · 79 km NE of this epicenter
- 7.2153 km W of Big Lagoon, CaliforniaJune 15, 2005 · 135 km NW of this epicenter
- 7.1The 1923 Humboldt County, California EarthquakeJanuary 22, 1923 · 26 km W of this epicenter
- 7.1121 km W of Ferndale, CaliforniaSeptember 1, 1994 · 81 km W of this epicenter
- 7.0136 km WSW of Brookings, OregonAugust 17, 1991 · 161 km NW of this epicenter
- 6.9103 km W of Pistol River, OregonJuly 13, 1991 · 201 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 21 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 3 recorded deaths. The most severe:
- 1969M4.8
Santa Rosa
2 Oct 1969 · 286 km away · intensity VIII
1 death$8 million damage
- 1954M6.6
Humboldt County
21 Dec 1954 · 80 km away
1 death$2 million damage
- 1932M6.5
Eureka
6 Jun 1932 · 45 km away · intensity VIII
1 deathModerate damage ($1–5M)
- 1992M7.1
Humboldt County: Ferndale, Petrolia
25 Apr 1992 · 38 km away · intensity VIII
$75 million damagetsunami
- 1980M7.2
North Coast
8 Nov 1980 · 79 km away · intensity VII
$2 million damage
- 1991M6.2
Honeydew, Whitethorn, Petrolia
17 Aug 1991 · 44 km away · intensity VII
Moderate damage ($1–5M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.