Reviewed by USGS65y ago
M6.9 earthquake northern Mid-Atlantic Ridge
Saturday, March 17, 1962, 20:47:34 UTC · 10.767°N, 43.255°W
A magnitude 6.9 earthquake struck northern Mid-Atlantic Ridge on Saturday, March 17, 1962, 20:47:34 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on February 22, 1929.
- Magnitude
- 6.9
- Strong · mw
- 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 earthquake
In context
How big was it, and why here?
Energy released
374 kilotons of TNT
That is about 25 times the Hiroshima bomb. It released about 785 times the energy of a magnitude 5.0.
Tectonic setting
14 km
from the nearest mapped plate boundary, between the African and South American 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 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 9 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.1northern Mid-Atlantic RidgeOctober 13, 1925 · 107 km E of this epicenter
- 7.1northern Mid-Atlantic RidgeDecember 2, 1918 · 88 km NW of this epicenter
- 7.0northern Mid-Atlantic RidgeFebruary 22, 1929 · 136 km E of this epicenter
- 6.7northern Mid-Atlantic RidgeJuly 13, 1906 · 75 km E of this epicenter
- 6.6northern Mid-Atlantic RidgeSeptember 3, 1927 · 25 km W of this epicenter
- 6.2northern Mid-Atlantic RidgeOctober 20, 1957 · 142 km E of this epicenter
- 5.8northern Mid-Atlantic RidgeMarch 9, 1961 · 180 km E of this epicenter
- 5.7northern Mid-Atlantic RidgeJuly 26, 1954 · 67 km NW 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:
- 1925M7.5
North Atlantic Ridge
13 Oct 1925 · 139 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.