Reviewed by USGS75y ago
M7.5 earthquake in South Indian Ocean
Saturday, December 8, 1951, 04:14:16 UTC · 34.229°S, 57.470°E
A magnitude 7.5 earthquake struck in South Indian Ocean on Saturday, December 8, 1951, 04:14:16 UTC, at a depth of 15.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.5
- Major · 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
3.0 megatons of TNT
That is about 198 times the Hiroshima bomb. It released about 6,237 times the energy of a magnitude 5.0.
Tectonic setting
84 km
from the nearest mapped plate boundary, between the Somali and Antarctic 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 200 km
USGS has not published any M2.5+ earthquake within 200 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 37 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.1Southwest Indian RidgeJanuary 21, 1933 · 33 km NE of this epicenter
- 7.0South Indian OceanApril 11, 1925 · 121 km E of this epicenter
- 7.0South Indian OceanSeptember 2, 1926 · 61 km E of this epicenter
- 6.9South Indian OceanMay 3, 1925 · 54 km SE of this epicenter
- 6.6South Indian OceanMay 19, 1925 · 50 km E of this epicenter
- 6.6Southwest Indian RidgeOctober 7, 1949 · 45 km NE of this epicenter
- 6.5South Indian OceanNovember 8, 1927 · 67 km E of this epicenter
- 6.5South Indian OceanMay 28, 1925 · 264 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:
- 1951M7.9
S
8 Dec 1951 · 50 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.