2. Introduction Next Chapter
2.1 The Need For A Deeper Understanding.
The July 17, 1998 tsunami of Aitape, Papua New Guinea brought to the public awareness with shocking reality not only the power of nature, but also our lack of understanding and preparedness against it. Three earthquake-triggered tsunami's, the largest only 10m in height, struck a 30 km stretch of coastline that housed 13,000 people over 7 villages, and completely wiped them off the face of the earth. While only 2,000 bodies have been found, as many as 8,000 are reported missing. Sissano Lagoon, the heart of the devastated area and where most of the casualties lie, was reported as being so contaminated by rotting corpses that all efforts to recover the bodies were officially abandoned, and a 120 sq. kilometre region was declared a "no-go zone". (Phillips, 1998)
Coastal populations are growing rapidly at rates higher than the national average due to migration from inland. According to the UNEP, most people in the (Asia -Pacific) region live along the coasts, with one quarter of the world's 75 largest cities being near or on the region's coastlines (www.unep.org 1997)
In a report for the American Association for the Advancement of Science, Hinrichsen observed that "of China's 1.2 billion people, over 677 million (56 percent) reside in 13 southeast and coastal provinces and two coastal municipalities -- Shanghai and Tianjin. Along much of China's 18,000 kilometers of continental coastline, population densities average over 600 per square kilometer" (www.aaas.org/ 1995)
Earthquakes will continue to occur as a natural phenomenom, and as some suggest, they are on the increase. Tsunamis will continue to be generated by oceanic earthquakes and affect the coastal populations. Since coastal populations are growing rapidly, and the fact that there is the possibility of earthqukes of greater magnitude, I believe the threat of a huge loss of human life and damage to property is growing at a rate that far exceeds the growing capacity for disaster warning, emergency response, and clean-up procedures. This, I also believe, will lead to a repeat of the situation found at Aitape, in Papua New Guinea, but with much greater devastating effect, especially if it were to occur on a densely populated coastal region such as the Pearl River Delta, in Guangdong province, China.
2.2 Identify and discuss important aspects of the inundation scenario which need to be examined in the project
The most important issue regarding the study of tsunami's is of course the destructive effects upon the human environment. Understanding tsunami's will help save lives. To assess the threat level and vulnerability of any given area, we need to take into consideration a number of factors.
Proximity to earthquakes zones is the primary factor, although all countries around the Pacific Rim are likely to experience tsunamis from quakes occurring anywhere in the Pacific. Earthquake magnitude, sea-floor depth (bathymetry) coastline topography and populations are all factors that contribute to an event and determine whether or not it will have disastrous effects. Not to be ignored however, is the emergency response and clean-up procedures that follow such an event, for these factors can also contribute heavily to loss of life. If for any reason, the emergency response crews are delayed or hindered in their work, or clean-up procedures are mishandled, these factors can add to the loss of human life well after the tsunami event itself. The 1998 PNG event is a prime example of a lack of disaster warning, excessively slow emergency response times, and poorly handled clean-up precedures, which, if prperly executed, could have resulted in minimising the death toll of the event.
The nature of the problem discussed in this paper is constructed of two very different sets of information which deal with two very different types of environments, ie. that which occurs in the water, and that which occurs on land. Both of these can be observed separately, and the problem itself does not exist until the two are brought together. For reasons discussed below, the Pearl River delta and environs is not at as great a risk of tsunami damage as Hawaii or Japan, yet the physical conditions present at Guangzhou are representative of the typical tsunami vulnerable environment at many places around the world. These two sets of information will be discussed separately, under the headings of Water and Land. Next I will examine existing models and work done by several researchers at the forefront of the field, to use as a basis for the hypothetical model which will be later applied as a hypothetical scenario with which to illustrate the disastrous effects of inundation upon coastal populations. As a visual aid to examining the problem, a special interactive map presentation (see below) has been devised to compare various types of maps with specific sets of data. Next I will set the parameters for a hypothetical scenario, and review the inundation process step by step as it would possibly apply to the Zhujiang estuary. Finally, I will discuss interesting or valuable issues that arise from examining such an event,
Guide To Navigating This Project In A WWW Browser
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Interactive Map Presentation
To take advantage of this facility, click on "Map Analysis" from the contents menu on the left, which brings up the map analysis text on the right. At the top, click "Map Menu" to bring up a map menubar in the left column. This has a selection of maps on various subjects from the Zhujiang delta region, that can be toggled easily for comparison. Once all the pages have been visited, the bwoser cache memory will store all the information, so flicking between maps will not be slow. Any map that has been selected has a toggle back to the analysis text, and most maps have additional toggels to allow you to rapidly compare certain maps. This presentation is designed to make the most of the "frames" capability of web browsers in enabling viewers an unique way of comparing maps. Feel welcome to toggle as much as you like!