April 30, 1919 Tsunami: Tonga Islands
A tsunami caused by a magnitude 8.1 earthquake began at Tonga Islands on April 30, 1919 at 07:17:17 UTC. The water rose as high as 2.5 meters. Its effects were recorded at 9 places in at least 5 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
- April 30, 1919, 07:17:17 UTC
- Source
- Tonga Islands
- Cause
- Earthquake
- Earthquake
- Magnitude 8.1, 25 km deep
- Maximum water height
- 2.5 m (8.2 ft)
- Runups recorded
- 9
- Tsunami intensity (Soloviev-Imamura)
- 1.5
- Tsunami magnitude (Iida)
- 1.3
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 18.352° S, 172.515° W
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.
1919, April 30 (erroneously the 9th). [30.IV; 7h17m05s; 19S., 172.5W; M=8.3 G&R]. On the Ha'apai Islands there was an earthquake lasting 2 1/2 minutes; on the island of Tongatapu there was a weak earthquake of 50 seconds duration.
The tsunami reached the island of Ha'apai 0.6 hours after the quake began where it had a height of 2.5 m, and it appeared at Apai [Apia] about 0.9 hours after the quake started, with a height of 0.4 m.
In Punaluu, on the Hawqiian Islands, a bay was completely drained at 7:30 [Local Time]. The water gradually returned, but on two occasions it rapidly receded - at about 09:00 and again at 10:30 [Local Time]. In Hilo, the tsunami had a amplitude of 0.6 m and a period of 70 minutes. In Honolulu, the tsunami had a height of 0.1 m and a period of 25 minutes.
The tsunami was recorded by tide gauges in California. The time of its passage to San Francisco was 11 hours, 23 minutes; to San Diego, 11 hours, 28 minutes.
(above from Reference #415)
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 |
|---|---|---|---|---|---|---|---|
| Ha'Apai | Tonga | 249 | 2.5 | Eyewitness observation of water height | day 30, 07:53 | ||
| Pago Pago, American Samoa, AS doubtful | US Territories | 491 | 2.4 | Eyewitness observation of water height | |||
| Apia, Upolu Island | Samoa | 507 | 0.4 | Tide gauge (half the maximum wave height) | day 30, 08:11 | ||
| Punaluu, Hawaii, HI, HI | United States | 4,545 | 0.9 | Tide gauge (half the maximum wave height) | day 30, 17:29 | ||
| Hilo, Hawaii, HI, HI | United States | 4,624 | 0.6 | Tide gauge (half the maximum wave height) | |||
| Honolulu, Oahu, HI, HI | United States | 4,669 | 0.1 | Tide gauge (half the maximum wave height) | day 30, 13:47 | ||
| San Francisco, CA, CA | United States | 8,126 | Tide gauge (half the maximum wave height) | day 30, 18:40 | |||
| San Diego, CA, CA | United States | 8,160 | 0.03 | Tide gauge (half the maximum wave height) | day 30, 18:41 | ||
| Tofino (Clayoquot),british Columbia, BC | Canada | 8,779 | 0.08 | Tide gauge (half the maximum wave height) | day 30, 20:00 |
More
Every tsunami in 1919The 1900sTsunamis of TongaThe 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 1472.