Various discussions have been made by many authors as respects the eruption mechanism of Krakatau caldera (e.g. Williams, 1941; Yokoyama, 1981; Self and Rampino, 1982; Yokoyama, 1982). Accumulation of geophysical data may provide important information to clarify the problem. Yokoyama and Hadikusumo (1969) have already established the gravity stations Krakatau Islands. The low residual anomalies…
The gravity survey on Krakatau Islands was first carried out by means of a land gravimeter in 1968 ( Yokoyama and Hadikusumo, 1969) and was supplemented by the present authors in 1982. The gravity points on the islands has reached 40 in number.
The author (1981) put an interpretation of the 1883 Krakatau eruption from the standpoint of geophysics. In the present paper, mainly the generation of the tsunami in the eruption will be discussed to supplement the previous interpretation.
Present situation of the Sumatra Island seems to indicate the clockwise rotation of about 40 degrees for Jawa (Fig.1). Ninkovich (1970) proposed a hypothesis that in the Late Cenozoic Sumatra rotated clockwise about 20 degrees and formed the present configuration. Moreover, Sasajima et al (1980) said that after the Triassic until the Early Tertiary, Sumatra should have rotated clockwise by 62.4…
Nature gave one of its warnings in late May 1883. The uninhabited, largely ignored island of Krakatau, in the middle of the Sunda Straits between the Indonesian islands of Sumatra and Java, suddenly stirred. Billowing clouds of smoke and booming thunder caused a small shiver of terror among the inhabitants of the nearby islands.
Indonesia is at the same time one of the most populous (5th in the world after PR China, India, USSR, USA), and one of the most volcanic, areas in the world, lying as it does at the intersection of three major plates. (The Geological background has been covered by Dr. Barber's contribution).
For the post-World War II period, most of the data are derived from observations by the then Volcanological Survey Division of the Geological Survey of Indonesia, where one of us (I.S) was attached since 1952.
Volcanic disaster and mitigation concern sany institution and its aspects with five principal elements and play such as) role volcanic crisis 1. Source of the crisis it self(the volcano) 2. Team of the Scientiste who study it 3. The administrative authorities 4. The Media 5. The population who live near by. In Indonesia the five elements of risk are coordinated by the government under sin…
The Quaternary volcanic rocks of Wilis Mountains can be divided into three morphocets : i.e the Jeding - Patukbanteng Morphocet, the Pawonsewu Morphocet, and the Argokalangan Morphocet. A sub-division of a morphocet is called a "morphonits", and eight morphonits have been recognized.
This is the sixth report on the progress of the project Volcano Monitoring and Research in Indonesia, covering the first quarter of 1987. Background information on the project and the organizational status of the Volcanological Survey of Indonesia (VSI) and the U.S. Geological Survey (USGS) were reported in an earlier report (Casadevall, 1985).