Reviewed by USGS43y ago
M5.8 earthquake south of Africa
Saturday, February 25, 1984, 07:16:00 UTC · 47.909°S, 31.775°E
A magnitude 5.8 earthquake struck south of Africa on Saturday, February 25, 1984, 07:16:00 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M6.2 on August 21, 1978.
- Magnitude
- 5.8
- Moderate · 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
8 kilotons of TNT
That is about 1/2 of the Hiroshima bomb. It released about 16 times the energy of a magnitude 5.0.
Tectonic setting
22 km
from the nearest mapped plate boundary, between the Antarctic and African 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 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 11 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.01942 Southwest Indian Ridge EarthquakeNovember 10, 1942 · 240 km SW of this epicenter
- 6.2south of AfricaJune 8, 1968 · 116 km S of this epicenter
- 6.2Prince Edward Islands regionAugust 21, 1978 · 63 km NE of this epicenter
- 6.1south of AfricaAugust 22, 1933 · 248 km SW of this epicenter
- 6.1south of AfricaFebruary 29, 1924 · 225 km S of this epicenter
- 6.1Prince Edward Islands regionMay 9, 1926 · 157 km NE of this epicenter
- 5.7south of AfricaApril 9, 1969 · 180 km SW of this epicenter
- 5.3Prince Edward Islands regionAugust 26, 1978 · 102 km NE 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:
- 1942M7.9
Prince Edward Island
10 Nov 1942 · 178 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.