Reviewed by USGS102y ago
M7.0 earthquake in South Indian Ocean
Saturday, April 11, 1925, 10:42:07 UTC · 34.565°S, 58.728°E
A magnitude 7.0 earthquake struck in South Indian Ocean on Saturday, April 11, 1925, 10:42:07 UTC, at a depth of 10.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.0
- Major · 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 earthquakeDashed circle: 200 km aftershock search area
In context
How big was it, and why here?
Energy released
548 kilotons of TNT
That is about 36 times the Hiroshima bomb. It released about 1,148 times the energy of a magnitude 5.0.
Tectonic setting
190 km
from the nearest mapped plate boundary, between the Somali and Antarctic plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
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 200 km
USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M6.9 on May 3, 1925. 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 1 M5.0+ earthquake within 300 km before this one (catalog from 1900; older records are less complete). The strongest: