August 1840 Tsunami: East Cape, New Zealand
A tsunami of unknown cause began at East Cape, New Zealand in August 1840. The water rose as high as 1 meters. Its effects were recorded at 2 places.
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 1840
- Source
- East Cape, New Zealand
- Cause
- Unknown
- Maximum water height
- 1 m (3.3 ft)
- Runups recorded
- 2
- Waters
- Ocean
- How certain
- Questionable tsunami
- Source location
- 37.610° S, 178.350° 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.
Reference #5324:
1840, August. Location of source is unknown. Tsunami observed at Hicks Bay and Te Araroa.
According to McKay (1966): Seismic waves had been experienced on the East Coast on several earlier occasions. In August, 1840 a wave of this character threw H.M.S. Buffalo on shore at Whitianga (Mercury Bay) and wrecked her. Tokato block (between Te Araroa and Hicks Bay) was strewn with fish.
The validity of this event is uncertain. The wrecking of the HMZ Buffalo at Whitianga, supposedly at the same time as the effects at Tokato, was caused by a storm in July 1840 rather than a tsunami (see for example, Riddle, J. 1996. Saltspray and sawdust; also reportedly in NZ shipwrecks). On the other hand, the stranding of fish that occurred west of East Cape often occurs in a tsunami, and in fact, could be considered an identifying feature of a tsunami. In-depth searching of diaries, few of which would be available along the east coast for this time, has not been carried out, and it is not known whether any unusual sea-level disturbances were experienced elsewhere. There are no trans-Pacific events in the ITDB database in 1840 that seem capable of reaching NZ.
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 |
|---|---|---|---|---|---|---|---|
| Te Araroa | New Zealand | 3 | 1 | Eyewitness observation of water height | |||
| Hicks Bay | New Zealand | 6 | 1 | Eyewitness observation of water height |
More
Every tsunami in 1840The 1800sTsunamis of New ZealandAlerts 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 5522.