October 17, 1974 Tsunami: Ritter Island, Papua New Guinea

Name: October 17, 1974 Tsunami: Ritter Island, Papua New Guinea
Start: 1974-10-17
Location: Ritter Island, Papua New Guinea

October 17, 1974 · 0.5 m · Definite tsunami

A tsunami caused by a volcano began at Ritter Island, Papua New Guinea on October 17, 1974. The water rose as high as 0.5 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

Tsunami warnings in force

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: October 17, 1974
Source: Ritter Island, Papua New Guinea
Cause: Volcano
Volcano: The eruption that caused it
Maximum water height: 0.5 m (1.6 ft)
Runups recorded: 2
Tsunami magnitude (Iida): -1
Waters: Ocean
How certain: Definite tsunami
Source location: 5.520° S, 148.121° 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 submarine volcano erupted in Melanesia, 600-900 miles west of Ritter Island (Sakar). The eruption was preceded by an earthquake followed by almost continuous tremors. The explosion column rose to a height of 400-500 m above sea level. The explosion was of the phreomagmatic or phreatic type. A rumble was heard and a tsunami of low amplitude was generated. (reference #417)

Ritter erupted briefly 17 October. An almost continuous series of seismic events was felt on neighboring islands and recorded throughout Papua New Guinea from 0600 to 0650 local time. The eruption and small tsunamis were observed from islands west of Ritter. Minor land-sliding occurred on Ritter Island itself. The island was under observation by a volcanologist from 18 to 21 October, but there were no signs of eruptive activity and no visible traces of recent activity except landslides. (reference #1630)

The sea was observed to dome up at the site of these explosions immediately before one of them, and sea disturbances continued at the site afterwards. A small tsunami was observed shortly after one of the explosions, although there were conflicting stories as to which one. The sea retreated at both Umboi and Sakar Islands and came back after a few minutes; the total rise and fall was not greater than that of a normal tide (possibly 0.2-0.5 m). Soft rumbles continued for a few minutes after the second explosion, and then all activity ceased. The 1974 explosion site was estimated to be 600-900 m west of the southern half of Ritter Island.' (reference #2682)

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
Tupinier Island (Sakar)	Papua New Guinea	12	0.5		Eyewitness observation of water height
Umboi Island (Ruk, Rooke, Siassi)	Papua New Guinea	16	0.5		Eyewitness observation of water height

Every tsunami in 1974 The 1900s Tsunamis of Papua New Guinea The eruption This day in weather history Alerts 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 2069.