August 15, 1984 Tsunami: Lake Monoun, Cameroon
A tsunami caused by a volcano, an earthquake and a landslide began at Lake Monoun, Cameroon on August 15, 1984. The water rose as high as 5 meters. Its effects were recorded at 1 place. It killed 37 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
Travel times
How long the first wave took to reach each part of the ocean, one line for each hour up to 24, estimated from the source and the depth of the sea.
The travel times are computed in your browser, which needs JavaScript.
- 1 to 4 hours
- 5 to 6 hours
- 7 to 14 hours
- 15 hours and more
Computed in your browser the way NOAA’s own travel time maps are: the wave travels at the square root of gravity times the depth, over NOAA’s ETOPO1 depths averaged to a 10 arc-minute grid. Checked against NOAA NCEI’s maps for 21 tsunamis over the first 24 hours, these lines fall within 10 minutes of NCEI’s at half the points compared and within 52 minutes at 9 in 10. They give when the first wave could arrive, not how high it is; bays, harbors and island chains finer than the grid can see it later. Not for use in a warning: see tsunami.gov.
The tsunami
- Date
- August 15, 1984
- Source
- Lake Monoun, Cameroon
- Cause
- Volcano, earthquake and landslide
- Volcano
- The eruption that caused it
- Maximum water height
- 5 m (16.4 ft)
- Runups recorded
- 1
- Waters
- Ocean
- How certain
- Probable tsunami
- Source location
- 6.250° N, 10.500° E
The toll
- Deaths
- 37 with the earthquake or eruption that caused it
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.
On 15 August 1984, Lake Monoun exploded in such a limnic eruption killing 37 people. Lake Monoun is located in the West Province of Cameroon within the Oku Volcanic Field. Its maximum length is about 1.5 km and it has a maximum depth of 60 m. Several people reported hearing a loud noise coming from the lake. A gas cloud reportedly emanated from a crater in the bottom of the eastern part of the lake. Survivors said that the whitish, smoke-like cloud, which smelled bitter and acidic, emerged from the water. Vegetation was flattened around the eastern part of the lake, probably by a tsunami-type wave that resulted from the large-scale disturbance of water produced by an emerging gas bubble. (reference #13041)
During the night of 15 to 16 August 1984, the density-stratified water mass within the deep crater in Lake Monoun overturned (Fig. 8B). The overturn was probably caused by a landslide from the crater's eastern rim, which in turn could have been triggered by a reported earthquake. The resulting break-down in stratification of the lake caused upwelling of deep water, effervescence and large-scale ebullition of the water in the crater basin. The sudden volumetric expansion of the escaping gas was of sufficient magnitude to cause locally a 5-m-high water wave on the eastern lake shore (Fig. 8C). (reference #13035)
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 |
|---|---|---|---|---|---|---|---|
| Lake Monoun | Cameroon | 75 | 5 | 100 | Eyewitness observation of water height |
More
Every tsunami in 1984The 1900sTsunamis of CameroonThe eruptionThis 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 5807.