付録4-4 カントリーレポート(2) インドネシア代表；Dr. Ilafude
NATURAL MARINE AND CLIMATE HAZARDS INDONESIA
By A.G. Ilahude*
Introduction
Indonesia is an archipelagic country, consisting of more than 17.000 islands, five of which are among the largest in the world. Stradling the equator, the archipelago is located between two continents, Asia and Australia and two oceans, the Indian and the Pacific. The total marine zone of Indonesia, inclusive Extended Economic Zone, is about 5 million square km, and the land area is 1.9 million square km.
The geology of Indonenia indicates that the western part of the archipelago, consisting of the islands of Sumatra, Jawa, Kalimantan and the adjacent small islands, is part of the Eurasian stable continental plate. The eastern part of the archipelago, consisting of Irian Jaya and Aru Islands is part of the actively moving continental Astralian plate. The middle part, consisting of the Sulawesi Island and the rest of the small islands, comprising the Maluku (Halmahera, Taliabu, Buru, Seram, Kai, Tanimbar and associated islands) and the Nusu Tenggara (Lombok, Sumbawa, Flores, Wetar, Sumba, Timor and their associated islands) are separate moving micro-plates.
Within Indonesia, the Eurasian continental plate is riding the Indian or Sundrayan oceanic plate which subducts under the former. The Astralian continental plate is pushing the Nusa Tenggara micro-plates and part of the Maluku (Tanimbar, Kai, Buru and Seram) micro-plates north and northwestward. In geological actuality these micro-plates belong to the Banda Arcs which is connected westward to the Sunda Arcs of Sumatra and Jawa. The two continuous Aros are generated and in collision with the Indian oceanic and Australian continental plates. The Sulawesi (Selayar, Muna, Buton, Peleng, Togiain etc.) and put of the Maluku (Taliabu, Mangole, Halmahera, Obi and others) micro-plates are pushed by the Caroline-Pacific plates into the fold formed by the Euracian and Indo-Astralian plates.
Most of the numerous tectonic plates of the Indonesian archipelago and the adjacent regions, large and small, are moving under each other, or against each other, at all times, through million of years. These activities produce complex geological feautures such as island arcs, mountain ranges, volcanoes, large and small faults, ocean basins, etc. that make up the geological condition found in Indonesia at present.
After million years of weathering processes many islands of the archipelago are covered by fertile soil, enriched by volcanic materials. In combination with the monsoon rain the soil is very much capable of supporting the growth of large tropical rain forest, large farming and plantation of various agricultural crops.
* Research and Development Center of Oceanology, Indonesian Institute of Sciences, Jakarta. Paper presented at the Meeting of Promoting and Strengthening the Oceanogr. Obs. For Clim. Change Prediction, October 5, 2000, Tokyo Japan.
