Reviewed by USGS94y ago
M6.1 earthquake south of Africa
Tuesday, August 22, 1933, 10:57:15 UTC · 49.849°S, 30.097°E
A magnitude 6.1 earthquake struck south of Africa on Tuesday, August 22, 1933, 10:57:15 UTC, at a depth of 10.0 km (shallow). It is the strongest earthquake within 300 km since an M6.1 on February 29, 1924.
- Magnitude
- 6.1
- 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
23 kilotons of TNT
That is about 2 times the Hiroshima bomb. It released about 48 times the energy of a magnitude 5.0.
Tectonic setting
19 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 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 1 M5.0+ earthquake within 300 km before this one (catalog from 1900; older records are less complete). The strongest: