July 17, 1998 Tsunami: Papua New Guinea

Ref #1315:

1998, July 17. A magnitude Ms 7.1 earthquake occurred near the northwest coast of Papua New Guinea 850 km northwest of Port Moresby, the capitol of Papua New Guinea (PNG). The earthquake, which occurred at 6:49 P.M. local time, was followed by a series of three catastrophic tsunami waves that devastated the villages of Sissano, Warupu, Arop (1 & 2) and Malol on the north coast of PNG killing at least 2,182, injuring 1,000, and displacing more than 10,000.

The earthquake was felt widely in PNG coastal communities. In the Aitape region, it was reportedly strong enough to make walking difficult and to knock objects over. The main shock was followed 20 min later by two moderate aftershocks that occurred so close together that they appeared to be a single event.

The three waves affected a 40-km length of coastline from the mouth of the Bliri River on the west to the town of Aitape on the east. This length of coastline was home to around 15,000 people before the tsunami. The area is predominantly tropical swamp land-a home to tribes that rely on subsistence farming and fishing and live in beach homes made of local materials. This section of coastline was particularly vulnerable because a narrow strip of land separates the ocean from Sissano Lagoon, a lagoon formed by a tsunami in 1907.

At many locations along this stretch of coastline the first wave arrived about 20 min. after the main shock (just after the first aftershocks). The trough of the first wave arrived soon after dark accompanied by loud sounds that drew curious tribesmen to the beach where they viewed the exposed sea floor. This was followed by an air blast that reportedly knocked people off their feet and a 7 to 10-meter tsunami crest. At Warupu and the Arop villages the second crest was described as riding on the back of the first and breaking over the villages, sweeping debris over the spit and washing it into the lagoon or 500 m inland from the coast. Trees were uprooted, and mature mangroves were broken off at distances of 1,300 m from the shore. Maximum wave heights reached nearly 15 m along a 20-km stretch of the lagoon area.

The villages of Arop and Warupu were entirely destroyed.

Ref #11882:

In 1998, the official estimate of deaths resulting from the tsunami was just over 2,200. Working back from the names listed on the memorials that were erected a year later, on 17 July 1999, authorities have been able to confirm 1,636 deaths (written communication from Tom Ritchie). The difference between the two figures remains unexplained. A further 1,000 were treated for serious wounds (p.48).

Ref #2707:

The death toll of the Aitape tsunami disaster has been confirmed at 2,182 as of 7 August 1998 while over 500 people are still missing. Major human damage are reported from three villages on sandbar of Sissano lagoon. Almost damage caused by the tsunami. Number of dead and missing is over 2,000. The population before the disaster was about 6,600 and the casualty reached a third of the population. Especially, over two thirds of the people were dead in Arop and Wrapu. The damage of this tsunami concentrated there. These two villages locate on a sand spit of Sissano Lagoon. Sissano Lagoon is 10 km in length, 3 km in width and 2 to 3 m in depth. It was made by the 1907 earthquake. Because the sand spit is 100 to 200 m in width and 2.5 to 3 m in height houses on this sand spit could be washed out easily by the tsunami. Its building was destroyed and only its foundation remained. The average maximum heights of the tsunami waves they crossed the Sissano sandbar was about 10 m. However, the wave height varies at different points long the sandbar and was as high as 15 m above the sea level at the former site of the Arop village. In this 1.2km long sector of the sandbar nothing was left standing now. There was a complete stripping of structures and trees.