Preview of Chapter 2 of "Are You Ready?"

Are you ready?

Chapter 2

Difficult to predict and almost impossible to escape

Roger Smith

Figure 2.3a The PNG coast near Vanimo

Photograph courtesy of Heather McElroy and Kerry Marshall

A taste of Chapter 2

This page gives a few images and a snippet or two of text to give a flavour of Chapter 2.

The booklet is printed in black and white (greyscale). You may wish to download, and possibly print, the sample pdf file to see what the booklet looks like.

Location of the tsunami disaster

Figure 2.1 Location of the undersea seismic disturbance (17 July 1998) which caused the tsunami in Papua New Guinea.
The earthquake that caused the tsunami in north-west Papua New Guinea in the early evening of 17 July 1998 occurred at 6:49 pm local time (8:49 GMT) and measured 7.1 on the Richter scale. It was located at 3.08°S and 141.76°E, about 18 to 20 kilometres off-shore and its focus was at a relatively shallow 33 kilometres from the surface. There was a major aftershock less than an hour later. There had been an earlier tremor (5.5 on the Richter scale) at 4.32°S and 143.52°E on 4 July 1998.

Figure 2.2 The PNG region and villages hit by the tsunami on 17 July 1998

Aspects of tsunami impact

An interview with Dr. Sairere also revealed that:

there were three waves not one.
as the waves approached, they changed from being parallel to the coast into a perpendicular position and swept sideways along the beach collecting the villages as they went.
the first wave washed away the trees, houses and canoes.
the first wave threw these objects into the tops of trees and broke them into small pieces.
many people tried to take refuge in the tops of trees but were ripped out of these as the waves swept by.
one of the worst affected areas was along the narrow spit and at the mouth of the Sissano lagoon.
the worst affected villages were Sissano, Warapu and Arop.
these villages had a combined population of approximately 4700 before the catastrophe.
two days after the tsunami struck these villages were found to have lost approximately 560 residents.
many of those who died were buried under sand or mud or drowned in the lagoon.
the hospitals at Aitape and Vanimo (the provincial capital of West Sepik) were quickly filled with the badly injured.
the injuries included bad bruises and abrasions, fractures, internal and head injuries.

Coastal settlement before the tsunami
	Figure 2.3b A beach scene in north west Papua New Guinea
Photograph courtesy of Heather McElroy and Kerry Marshall


	Figure 2.3c Typical village house in NW PNG	Figure 2.3d Typical coastal settlement in NW PNG
	Photographs courtesy of Heather McElroy and Kerry Marshall

A snippet of the immediate aftermath

Within a few days of the disaster life was depicted as being even more difficult for the survivors because of the many dead bodies (humans and animals) and uprooted and tangled vegetation that was beginning to rot in the hot tropical sun. The air had become filled with an overpowering stench. The huge mass of debris that had been created by the bulldozing tsunami was shown dumped into the coastal lagoon or in great matted piles in locations hundreds of metres away from the coast where the waves had finally run out of energy.

There are simple explanations

Figure 2.4 A simple explanation of the cause of the tsunami

Box 2.1 Tsunami
Tsunami was adopted as a hazard term, for general use, in 1963 by an international scientific conference. It is a Japanese word represented by two characters:
'tsu' - meaning harbour
'nami' - meaning wave

A tsunami can be generated by any disturbance (e.g. earthquake, landslide, volcanic eruption) in the ocean floor that displaces a large water mass from its equilibrium position. Disturbances can occur in oceans, seas, bays or lakes. The similar, but oscillating effect in a lake is called a 'seiche' and may also result from strong winds or atmospheric pressure variations. Once the series of waves (created by this sudden distortion of the earth's crust under the sea) starts moving, it causes no perceptible rise in the open sea. Each wave can be hundreds of kilometres long but only a few centimetres or metres from trough to crest (See Figure 2.4).

Even though tsunamis have their greatest impacts on coasts through the action of giant coastal waves they are considered as geological hazards because they are initiated by movement of the earth's crust. For people on shore there is little warning of an approaching tsunami. The first indication is often a sharp swell followed by a sudden outrush of water that often exposes the shore area. This exposure takes place just before the first wave arrives.

The worst recorded tsunami disaster in recent history followed the volcanic eruption of the island of Krakatoa in 1883 when 35 metre waves travelling at 560 to 720 km/h crashed into Java and Sumatra drowning 36,420 people.

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