August 20, 2011 Tsunami: Vanuatu Islands
A tsunami caused by a magnitude 7.1 earthquake began at Vanuatu Islands on August 20, 2011 at 16:55:02 UTC. The water rose as high as 0.19 meters. Its effects were recorded at 4 places in at least 2 countries.
Where the waves reached
The source (white) and every runup with a place, colored by the water height recorded there. A ring is a runup NCEI marks doubtful.
- Under 1 m
- 1 to 3 m
- 3 to 10 m
- 10 to 30 m
- 30 m and more
- Height not recorded
The tsunami
- Date
- August 20, 2011, 16:55:02 UTC
- Source
- Vanuatu Islands
- Cause
- Earthquake
- Earthquake
- Magnitude 7.1, 32 km deep
- Maximum water height
- 0.19 m (0.6 ft)
- Runups recorded
- 4
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 18.365° S, 168.143° E
The toll
The record gives no deaths, injuries or damage for this tsunami.
What the record says
NCEI’s account, from the sources it cites.
A major earthquake with a moment magnitude of 7.1 (USGS magnitude) occurred at 16:55:02 UTC 20 August 2011 (day 232) and was located 39 miles/63 km SSW of Port-Vila, Efate, Vanuatu (18.260S, 168.069E, 25.2 mi/40.6 km depth--USGS location).
A second major earthquake with a moment magnitude of 7.0 (USGS magnitude) occurred at 18:19:02 UTC 20 August 2011 (day 232) and was located 42 miles/69 km SSW of Port-Vila, Efate, Vanuatu (18.287S, 168.132E, 17.7 mi/28.5 km depth--USGS location).
(all above from reference 9763)
Every runup
Nearest the source first. Heights are above sea level at the time; a tide gauge reads half the wave’s full height.
| Where | Country | Km from source | Water height, m | Inland, m | Measured by | First wave, UTC | Deaths |
|---|---|---|---|---|---|---|---|
| Port Vila, Efate Island | Vanuatu | 70 | 0.19 | Tide gauge (half the maximum wave height) | day 20, 17:08 | ||
| Luganville | Vanuatu | 331 | 0.07 | Tide gauge (half the maximum wave height) | day 20, 17:40 | ||
| Hienghene | New Caledonia | 423 | 0.08 | Tide gauge (half the maximum wave height) | day 20, 17:49 | ||
| Ouinne | New Caledonia | 429 | 0.14 | Tide gauge (half the maximum wave height) | day 20, 17:46 |
More
Every tsunami in 2011The 2000sTsunamis of VanuatuThe earthquakeThis day in weather historyAlerts in force
Sources
Tsunami events and runups from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. NCEI tsunami event 5437.