Minggu, 17 Oktober 2010

Anak Krakatau


View of Anak Krakatau from the W (May 2008). The 2007 crater is seen degassing on the left, the principle cone is in the center, the rim of pre-1960 cone is slightly to the right.
Location of Anak Krakatau in the Krakatau archipelago (N at top)
Rough sketch of Anak Krakatau in 2008
Following the 1883 eruption, the former cones of Danan and Perboewatan, as well as most of Rakata disappeared into the sea. Only the S flank of Rakata remained aswell as the older islands of Sertung and Panjang. Between these a nearly 300m deep depression (the 1883 caldera) was located. No significant eruptive activity was reported between 1883 and 1927. However, in December 1927, surtseyan submarine activity was reported in an area on the NE flank of the depression which had a depth of about 180m following the 1883 eruption. The activity was initially attributed to a series of vents along a 500m fissure trending along the same NNW-SSE fault line as the former craters of Perboewatan, Danan and Rakata. Activity

Krakatau Volcano - Indoneasa

Early in the morning of May 20, 1883, the captain of the German warship Elizabeth reported seeing an ~11-km-high cloud of ash and dust rising above the uninhabited island of Krakatau, thus documenting the first eruption from this Indonesian island in at least two centures. Over the ensuing two months, crews on commercial vessels and sightseers on charted ships would experience similar spectacles, all of which were associated with explosive noises and churning clouds of black to incandescent ash and pumice. From a distance, the largest of these natural fanfares impressed the local inhabitants on the coastal plains of Java and Sumatra, creating a near-festive environment. Little did they realize, however, that these awe-inspiring displays were only a prelude to one of the largest eruptions in historic times. A series of cataclysmic explosions began at mid-day on August 26, and ended on August 27 with a stupendous paroxysmal eruption. On this day, the northern two-thirds of the island collapsed beneath the sea, generating a series of devasting pyroclastic flows and immense tsunamis that ravaged adjacent coastlines. The events that began on August 26 would mark the last 24 hours on earth for over 36,000 people, and the destruction of hundreds of coastal villages and towns.