Reviewed by USGSOregon42y ago
M4.6 earthquake 250 km WNW of Bandon, Oregon
Thursday, March 14, 1985, 05:53:13 UTC · 43.760°N, 127.375°W
A magnitude 4.6 earthquake struck 250 km WNW of Bandon, Oregon on Thursday, March 14, 1985, 05:53:13 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M6.5 on March 13, 1985.
- Magnitude
- 4.6
- Light · mb
- Depth
- 10 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
120 tons of TNT
That is about 1/126 of the Hiroshima bomb. A magnitude 5.0 releases about 4 times more energy.
Tectonic setting
40 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
10 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 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M4.4 on April 11, 1985. 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 102 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 6.5259 km W of Bandon, OregonMarch 13, 1985 · 32 km SW of this epicenter
- 6.5235 km W of Port Orford, OregonAugust 5, 1910 · 111 km S of this epicenter
- 6.4213 km W of Port Orford, OregonAugust 20, 1952 · 101 km S of this epicenter
- 6.4169 km W of Crescent City, CaliforniaMarch 24, 1949 · 263 km S of this epicenter
- 6.4187 km W of Trinidad, CaliforniaDecember 31, 1915 · 297 km S of this epicenter
- 6.4off the coast of OregonSeptember 11, 1928 · 257 km W of this epicenter
- 6.3off the coast of OregonMay 8, 1968 · 64 km W of this epicenter
- 6.3off the coast of OregonSeptember 25, 1936 · 159 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 · 234 km away
Severe damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.