The principle feauture of the tsunamis in the archipelago is that all of them are locally generated immediately followed the cause within minutes. Nothing can be done in terns of predicting their arrival. Only after the occurrence, help can be provided such as actions of ameliorating the consequences and aiding the affected people to start their life again.
Of the 81.000 km of the coastline in the archipelago, most of it are potentially threaten by tsunamis. Therefore it is necessary to indentify which part of the coast lines are close to faults or to areas often hit by earthquakes.
Red Tide
Red tide is a natural phenomenon caused by the growth explosion of certain species of marine phytoplankton. When the explosion occurs, the sea water colour of blueish or blue-greenish hue turns to red, redish-brown, yellowigh-green or even white, depending on the species of the plankton.
Red tide is often hazardous because of the toxic substances produced by the phytoplankton, both to other marine organisms, fisheries and man. The harmful plankton comprises three large groups the diatom such as Chaetoceros and Coscinodiscus, and the dinooflagelate such as Noctiluca and the cyanobacteria such as Trichodesmium.
About 25 species belonging to four genera that are mostly creating harmful algal bloom (HAB) hazardous to other marine organisms and man are known to be present in Indonesian Waters. The recorded red tide occurrences in Indonesia for example are at Lewotobi, Flores (23 November 1983), Sebatik Island, Kalimantan (9 January 1988), Lampung, Sumatra (September 1991) and Jakarta Bay (1992). Outside Indonesia, the harmfull algal blooms have also been recorded such as in Papua New Guinea (1972), Brunai Darul Salam (1983). The islands of Palau, Guam, Singapore, and those in Malaysia, Thailand, Australia and New Zealand have also been the locality of HAB.
The harms caused by HAB include paralythic and diarrhetic shellfish poisoning in man, mass mortality of organisms due to anoxyfication, damaging the shrimp aquaculture in ponds and fish poisoning of large areas. The resulting consequences in terms of dollar can be large.
Oceanographic Observation Needed
To face the occurrence of the natural marine hazards and to ameliorate their adverse consequences in people' lives and properties, and in the infrastructures of the country's economical and cultural developments, it is very necessary to know in advance and to predict when will the disasters occurrs. Effort toward this goal can be achieved if the oceanographical and meteorological conditions of the large areas of the archipelago can be observed and studied.
Data on wind strength and direction, air temperature, and pressure, air humidity and composition, solar radiation, rain and cloud cover need be collected to investigate the climate characteristics and their variability.
