July 9, 1847 Tsunami: Azores, Portugal
A tsunami caused by a landslide began at Azores, Portugal on July 9, 1847. The water rose as high as 7 meters. Its effects were recorded at 2 places. It killed 10 people, counting the earthquake or eruption that caused it.
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
- July 9, 1847
- Source
- Azores, Portugal
- Cause
- Landslide
- Maximum water height
- 7 m (23.0 ft)
- Runups recorded
- 2
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 39.483° N, 31.233° W
The toll
- Deaths
- 10
- Missing
- 100 with the earthquake or eruption that caused it
- Injuries
- 100
Where the literature gives no number, NCEI records a description on a scale of 1 to 4, printed here in its words. Damage is in millions of US dollars of the year of the event, not adjusted for inflation.
What the record says
NCEI’s account, from the sources it cites.
Reference #13057:
On 9 July 1847 a major landslide occurred on Ponta dos Fenais (39°29′ N, 31°14′ W), between Faja Grande and Ponta Delgada, Flores Island, where, according to Macedo [1871] 1981, there fell a ‘large portion of a rock, which filled more than 770 metres of sea offshore with more than 1100 metres width and 66 metres depth, forming two separated islets being one continued to land and the other distant of it 220 metres both with grove that collapsed along with the mountain and that seems to have been born there. It was this collapse felt throughout the island and still in Corvo, rising at the place of the disaster great smoke and boil of water that rose to 60 metres, appearing on the waters and on the coast an immensity of dead fish’ (vol. II, pp. 120–121)
[...]This current swept along the entire coast of Flores Island for about half an hour, leaving vast areas of the sea bottom uncovered. The sea then returned with great energy and velocity and some people were caught completely unaware: about 100 were wounded and 10 died, five between Faja Grande and Fajazinha, three in Santa Cruz and two on Corvo Island.
Ferreira (2005) and Pacheco et al. (2006) consider that the Quebrada Nova landside was a rotational slip landslide and Borges et al. (2008) estimate a tsunami run-up of around 5–7 m on Flores and Corvo islands.
[...]The waves generated by the Quebrada Nova event affected the entire coast of Flores Island, also reaching Corvo Island, causing a total of 10 deaths and hundreds of wounded in these islands. This is, in fact, the deadliest tsunami in the Azores archipelago.
Reference #11861:
the 1847 failure of a sea-cliff at Quebrada Nova on the western seaboard of Flores island which produced a 5-7 m-high tsunami that killed 10 people and injured around 100 on the islands of Corvo and Flores.
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 |
|---|---|---|---|---|---|---|---|
| Flores Island, Azores | Azores | 3 | 7 | Eyewitness observation of water height | 8 | ||
| Corvo Island, Azores | Azores | 27 | 7 | Eyewitness observation of water height | 2 |
More
Every tsunami in 1847The 1800sTsunamis of PortugalThis 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 5810.