Reviewed by USGSOregon59y ago
M5.5 earthquake 230 km W of Langlois, Oregon
Thursday, May 9, 1968, 03:03:01 UTC · 43.312°N, 127.235°W
A magnitude 5.5 earthquake struck 230 km W of Langlois, Oregon on Thursday, May 9, 1968, 03:03:01 UTC, at a depth of 18.5 km (shallow). It is the strongest earthquake within 300 km since an M6.3 on May 8, 1968.
- Magnitude
- 5.5
- Moderate · mw
- Depth
- 19 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
3 kilotons of TNT
That is about 1/5 of the Hiroshima bomb. It released about 6 times the energy of a magnitude 5.0.
Tectonic setting
4 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
19 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 75 km
USGS has not published any M2.5+ earthquake within 75 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 61 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 · 271 km SE of this epicenter
- 6.8off the coast of Northern CaliforniaJuly 6, 1934 · 276 km SE of this epicenter
- 6.5235 km W of Port Orford, OregonAugust 5, 1910 · 62 km S of this epicenter
- 6.4213 km W of Port Orford, OregonAugust 20, 1952 · 50 km S of this epicenter
- 6.4169 km W of Crescent City, CaliforniaMarch 24, 1949 · 213 km SE of this epicenter
- 6.4187 km W of Trinidad, CaliforniaDecember 31, 1915 · 246 km S of this epicenter
- 6.4off the coast of OregonSeptember 11, 1928 · 266 km W of this epicenter
- 6.3off the coast of OregonMay 8, 1968 · 76 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 2 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 · 259 km away
Severe damage ($5–24M)tsunami
- 1922M7.6
Northern
31 Jan 1922 · 294 km away
Limited damage (under $1M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.