Historical tsunamis · Oct 6, 1987, 4:19 AM UTC
1987 Tonga Islands tsunami
Tonga
The tsunami of Oct 6, 1987, 4:19 AM UTC originated near Tonga Islands (Tonga).
Key facts
- Date
- Oct 6, 1987, 4:19 AM UTC
- Cause
- Earthquake
- Magnitude
- M7.3
- Depth
- 16 km
- Maximum documented water height
- 0.25 m
- Observation records
- 2
- Countries affected
- 2
It was triggered by a magnitude 7.3 earthquake at a depth of 16 km.
The highest documented water height was 0.25 m.
2 observation sites in 2 countries are recorded.
Outside the source country, the earliest documented arrival was at Pago Pago, American Samoa (USA Territory) after 0:51 h.
Map of observation sites
2Each dot is a documented observation site; colour and size show the observed water height. The triangle marks the source.
Tsunami arrival times
Documented arrival times from the NOAA/NCEI database, showing the earliest recorded location per country. Coverage is incomplete: a country without an entry was not necessarily spared.
- 0:00 hEarthquake (origin) · Oct 6, 1987, 4:19 AM UTC
- 0:51 hUSA Territory · Pago Pago, American Samoa · 0.12 m
1 places with a documented arrival time
Observations by country
| Country | Observation records | Maximum documented water height | Deaths | Earliest arrival |
|---|---|---|---|---|
| USA Territory | 1 | 0.12 m Pago Pago, American Samoa | — | 0:51 h |
 Samoa | 1 | 0.02 m Apia, Upolu 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 |
|---|---|---|---|
| Pago Pago, American Samoa · As | 0.12 m | 437 km | USA Territory |
| Apia, Upolu Island | 0.02 m | 458 km | Samoa |
More tsunamis
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.