Historical tsunamis · Nov 30, 1983, 5:46 PM UTC
1983 Chagos Archipelago Region tsunami
UK Territory
The tsunami of Nov 30, 1983, 5:46 PM UTC originated near Chagos Archipelago Region (UK Territory).
Key facts
- Date
- Nov 30, 1983, 5:46 PM UTC
- Cause
- Earthquake
- Magnitude
- M7.7
- Depth
- 10 km
- Maximum documented water height
- 1.50 m
- Damage
- limited (under US$ 1 million)
- Observation records
- 2
- Countries affected
- 2
It was triggered by a magnitude 7.7 earthquake at a depth of 10 km.
The highest documented water height was 1.50 m (Diego Garcia, Chagos Islands, UK Territory).
2 observation sites in 2 countries are recorded.
Damage is estimated at limited (under US$ 1 million).
Map of observation sites
2Each dot is a documented observation site; colour and size show the observed water height. The triangle marks the source.
Observations by country
| Country | Observation records | Maximum documented water height | Deaths | Earliest arrival |
|---|---|---|---|---|
| UK Territory | 1 | 1.50 m Diego Garcia, Chagos Islands | — | — |
 Seychelles | 1 | 0.04 m Victoria, Mahe Island | — | — |
Highest documented water heights
2 / 2Individual documented observations for this event. Heights come from different measurement types and sources; not every location has a measured height.
| Location / station | Observed height | Distance from source | Country |
|---|---|---|---|
| Diego Garcia, Chagos Islands | 1.50 m | 57 km | UK Territory |
| Victoria, Mahe Island | 0.04 m | 1,862 km | Seychelles |
Source: NOAA National Centers for Environmental Information (NCEI), Global Historical Tsunami Database. Confirmed events only. Deaths and damage are database estimates; older records are incomplete. Water heights come from different types of observation.