Reviewed by USGSOregon75y ago
M6.4 earthquake 213 km W of Port Orford, Oregon
Wednesday, August 20, 1952, 15:25:07 UTC · 42.874°N, 127.096°W
A magnitude 6.4 earthquake struck 213 km W of Port Orford, Oregon on Wednesday, August 20, 1952, 15:25:07 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M6.4 on March 24, 1949.
- 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
28 km
from the nearest mapped plate boundary, between the Pacific and Juan de Fuca 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 has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 46 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 · 224 km SE of this epicenter
- 6.884 km W of Ferndale, CaliforniaFebruary 9, 1941 · 290 km SE of this epicenter
- 6.8off the coast of Northern CaliforniaJuly 6, 1934 · 229 km SE of this epicenter
- 6.552 km WNW of Big Lagoon, CaliforniaJuly 15, 1918 · 261 km SE of this epicenter
- 6.5235 km W of Port Orford, OregonAugust 5, 1910 · 26 km SW of this epicenter
- 6.4169 km W of Crescent City, CaliforniaMarch 24, 1949 · 164 km SE of this epicenter
- 6.4187 km W of Trinidad, CaliforniaDecember 31, 1915 · 197 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 4 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1700M9.0
Cascadia Subduction Zone
27 Jan 1700 · 290 km away
Severe damage ($5–24M)tsunami
- 1865
Fort Humboldt, Eureka
1 Oct 1865 · 299 km away · intensity IX
Moderate damage ($1–5M)
- 1922M7.6
Northern
31 Jan 1922 · 247 km away
Limited damage (under $1M)
- 1873M6.7
Northern
23 Nov 1873 · 272 km away · intensity VIII
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.