Reviewed by USGSCalifornia78y ago
M6.4 earthquake 169 km W of Crescent City, California
Thursday, March 24, 1949, 20:56:56 UTC · 41.555°N, 126.213°W
A magnitude 6.4 earthquake struck 169 km W of Crescent City, California on Thursday, March 24, 1949, 20:56:56 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.5 on October 3, 1941.
- Magnitude
- 6.4
- Strong · mw
- Depth
- 15 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 earthquake
In context
How big was it, and why here?
Energy released
69 kilotons of TNT
That is about 5 times the Hiroshima bomb. It released about 145 times the energy of a magnitude 5.0.
Tectonic setting
76 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
15 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 100 km
USGS lists 1 M2.5+ earthquake within 100 km in the following 30 days. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 67 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 · 65 km SE of this epicenter
- 7.1The 1923 Humboldt County, California EarthquakeJanuary 22, 1923 · 155 km SE of this epicenter
- 6.884 km W of Ferndale, CaliforniaFebruary 9, 1941 · 128 km SE of this epicenter
- 6.8off the coast of Northern CaliforniaJuly 6, 1934 · 69 km SE of this epicenter
- 6.552 km WNW of Big Lagoon, CaliforniaJuly 15, 1918 · 127 km E of this epicenter
- 6.5235 km W of Port Orford, OregonAugust 5, 1910 · 165 km NW of this epicenter
- 6.568 km W of Ferndale, CaliforniaOctober 3, 1941 · 153 km SE of this epicenter
- 6.5The 1932 Eureka, California EarthquakeJune 6, 1932 · 186 km SE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 1 recorded deaths. The most severe:
- 1932M6.5
Eureka
6 Jun 1932 · 186 km away · intensity VIII
1 deathModerate damage ($1–5M)
- 1865
Fort Humboldt, Eureka
1 Oct 1865 · 156 km away · intensity IX
Moderate damage ($1–5M)
- 1922M7.6
Northern
31 Jan 1922 · 86 km away
Limited damage (under $1M)
- 1923M7.1
Northern
22 Jan 1923 · 155 km away · intensity VIII
Limited damage (under $1M)tsunami
- 1873M6.7
Northern
23 Nov 1873 · 190 km away · intensity VIII
Limited damage (under $1M)tsunami
- 1941M6.6
Northern
9 Feb 1941 · 142 km away · intensity VI
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.