Krakatoa is infamous for its violent Plinian eruption in , that destroyed the previous volcanic edifice and enlarged its caldera. Collapse of the former volcanic edifice, perhaps in AD, had formed a 7-km-wide caldera.
Remnants of this ancestral volcano are preserved in Verlaten and Lang Islands; subsequently Rakata, Danan and Perbuwatan volcanoes were formed, coalescing to create the pre Krakatoa island. Caldera collapse during the catastrophic eruption destroyed Danan and Perbuwatan volcanoes, and left only a remnant of Rakata volcano. This eruption, the 2nd largest in Indonesia during historical time the most violent being the eruption of Tambora in , caused more than 36, fatalities, most as a result of devastating tsunamis that swept the adjacent coastlines of Sumatra and Java.
Pyroclastic surges traveled 40 km across the Sunda Strait and reached the Sumatra coast. After a quiescence of less than a half century, the post-collapse cone of Anak Krakatoa "Child of Krakatoa" was constructed within the caldera at a point between the former cones of Danan and Perbuwatan.
Anak Krakatau has been the site of frequent eruptions since Krakatau volcano Caldera m 2, ft. Violent eruption of Krakatau showering the summit cone with incandescent bombs. Show interactive Map. Last earthquakes nearby. View recent quakes. Zoom onto the expanding ejected plug of the explosion; only few of the blocks are actually glowing red.
At night, this means that most blocks won't be visible! Photo: To Photo: V. A barrage of bombs hits the water, some quite far from the shore. Photo: Iris Karinkanta. Mount Krakatoa is an example of a stratovolcano, a tall, conical volcano with multiple strata of solidified lava, tephra, as well as volcanic ash.
Most of the popular eruptions have been made by stratovolcanoes. Other known stratovolcanoes are Mount St. Helens and Mount Pinatubo. Indonesia is the country that holds the biggest number of active volcanoes, at Iceland, another volcano-dotted country, holds about the same number of volcanoes but not all are as active as those in Indonesia.
We have some articles in Universe Today that are related to Mount Krakatoa. Here are two of them:. Tired eyes? We were obliged to cover up the skylights to save the glass, while our feet and heads had to be protected with boots and sou-westers.
About six the fall of larger stones ceased, but there continued a steady downpour of a smaller kind, most blinding to the eyes, and covering the deck to a depth of three or four inches very speedily. While an intense blackness covered the sky and land and sea, we sailed on our course, until at seven P. Chains of fire appeared to ascend and descend between it and the sky, while on the S.
The wind, though strong, was hot and choking, sulphurous, with a smell as of burning cinders, some of the pieces falling on us being like iron cinders. The lead came up from the bottom at thirty fathoms quite warm. The same impenetrable darkness continued, while the roaring of Krakatoa was less continuous but more explosive in sound; the sky one second intensely black, the next a blaze of light.
The mast-heads and yard-arms were studded with corposants, and a peculiar pink flame came from fleecy clouds which seemed to touch the mast-heads and yard-arms.
At eight hoisted our signal letter, but got no answer. We saw a wave rush right on to the Button island, apparently sweeping entirely over the southern part, and rising half-way up the north and east sides, fifty or sixty feet, and then continuing on to the Java shore. This was evidently a wave of translation, and not of progression, for it was not felt at the ship. This we saw repeated twice, but the helmsman said he saw it once before we looked.
At the same time the sky rapidly covered in; the wind came out strong from S. We set the side lights, placed two men on the lookout forward, the mate and second mate on either quarter, and one man washing the mud from the binnacle glass.
We had seen two vessels to the N. This horrible state and downpour of mud and debris continued until 1. By two P. Up to midnight the sky hung dark and heavy, a little sand falling at times, and the roaring of the volcano very distinct, although we were fully seventy-five miles from Krakatoa. Such darkness and such a time in general, few would conceive, and many, I dare say, would disbelieve.
The ship from truck to water-line was as if cemented; spars, sails, blocks, and ropes were in a horrible state; but, thank God, no one was hurt, nor was the ship damaged.
But think of Anjer, Merak, and other little villages on the Java coast! The northwestern part of Krakatoa Island had disappeared. The line of fracture began at a point south of Lang Island, and formed an arc of a circle passing through the peak to the western side of the island.
Boats from the U. Juniata entered the crater-like area, concave to the northward, and sounded along the face of the heights; but no bottom could be found with twenty fathoms of line. Prior to the eruption, Verlaten and Lang islands were green with trees and foliage; they are now covered with scoria. Eastward of Verlaten a small island had formed; small necks of land had been thrown out from the eastern side of Verlaten and the western point of Krakatoa.
The Polish Hat had disappeared, but a new rock, about twenty feet in height and as many in diameter, now existed in Krakatoa channel, near to the southern point of Lang Island. Within ten yards of this rock there were eight fathoms of water.
At the place occupied by the Polish Hat the boats found no bottom with twenty fathoms of line, while at the spot where the volcano had been so active later soundings showed no bottom at one hundred and sixty-four fathoms, nearly one thousand feet.
To the northward and eastward two new islands, Steers and Calmeyer, had formed, where before the eruption were thirty to forty fathoms of water. It has been thought that the first great waves on the evening of the 26th were caused by a portion of Krakatoa being shot out northwards for eight miles, and dropped where now is Steers Island; while the terrific detonation on the 27th, and the greater wave accompanying it, resulted perhaps from that still more titanic effort which lifted the greater portion of Krakatoa, hurled it through the air over Lang Island, and plunged it into the sea where Calmeyer Island now blocks the old East Passage.
The captain of the Juniata stated in his report that he anchored off the site of Anjer, and that "the buoys which mark the line of the submarine cable to Telok Betong, Sumatra, and the base of the light-house at Fourth Point are the only monuments of Anjer. The plain northward of Anjer peak was swept by the flood of waters, and nothing remains but the vine-like roots of the cocoa palm and some scattered and ghastly relics of the inhabitants Communication with Telok Betong is now interrupted by masses of floating pumice wedged in Lampong Bay.
And yet another reported that on December 21, , in the S. The tidal phenomena which followed this convulsion are particularly interesting. The waves formed in the narrow strait issued into the oceans east and west, and started on their journey around the globe. The undulations were registered at Mauritius, the Seychelles, in South Africa, and on the shores of the Pacific Islands on the same day that the Java villages were swept away.
The waves continued their course, crossed each other at the antipodes of Krakatoa, and returned to the spot from which they had started. Four times did they go around the earth before the equilibrium of the sea was so far restored as to be insensible to instruments.
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