Reviewed by USGS59y ago
M6.3 earthquake off the coast of Oregon
Wednesday, May 8, 1968, 12:17:13 UTC · 43.549°N, 128.114°W
A magnitude 6.3 earthquake struck off the coast of Oregon on Wednesday, May 8, 1968, 12:17:13 UTC, at a depth of 13.4 km (shallow). It is the strongest earthquake within 300 km since an M6.4 on August 20, 1952.
- Magnitude
- 6.3
- Strong · mw
- Depth
- 13 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: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
47 kilotons of TNT
That is about 3 times the Hiroshima bomb. It released about 99 times the energy of a magnitude 5.0.
Tectonic setting
9 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
13 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 2 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.5 on May 9, 1968. 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 51 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 6.5235 km W of Port Orford, OregonAugust 5, 1910 · 106 km SE of this epicenter
- 6.4213 km W of Port Orford, OregonAugust 20, 1952 · 112 km SE of this epicenter
- 6.4169 km W of Crescent City, CaliforniaMarch 24, 1949 · 271 km SE of this epicenter
- 6.4187 km W of Trinidad, CaliforniaDecember 31, 1915 · 299 km SE of this epicenter
- 6.4off the coast of OregonSeptember 11, 1928 · 195 km W of this epicenter
- 6.3off the coast of OregonSeptember 25, 1936 · 106 km SW of this epicenter
- 6.3192 km WSW of Pistol River, OregonSeptember 28, 1945 · 245 km SE of this epicenter
- 6.2off the coast of OregonDecember 30, 1944 · 180 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 1 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 · 296 km away
Severe damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.