Wednesday, February 25, 2009

History Channel: "Krakatoa" episode in "How the Earth Was Made"


On Tuesday, Feb. 24, 2009 the History Channel aired, at 9 PM, an important episode of “How the Earth Was Made” episode "Krakatoa". Unfortunately, this was the same time as President Obama’s speech, but it will be reshown several times and could be recorded; it is available on DVD at this link.

The episode resembles a similar “Mega-Disasters” episode aired in November 2007.

But the program starts with a focus on the “new” volcano Anak Krakatoa (the Son of Krakatoa) in the channel (Sundo Straits) between Java and Sumatra, Indonesia. One scientist says that the cone has grown 300 feet between two visits over just a few years. It is now 1030 feet high, but did not exist until 1927. It has had many small earthquakes and shows a lot of subsurface activity. The show presented analysis of “lava bombs”, which contain do not contain of silica as Krakatoa’s did. The magma comes from several miles deep. In time the magma of the new volcano will gradually become more viscous, a sign of another possible explosion.

The original explosion in 1883 (actually the last of a series over several days) created the loudest noise ever heard on Earth, according to the program (even louder than a thermonuclear explosion).

The program goes on to show how the pyroclastic blast rode along the ocean channel at 200 mph to the surrounding islands, and how the blast created a 120 foot tsunami.

It later looks at sulfuric acid levels in ice core samples near Ross Island, Antarctica, with another eruption in Roman times. The studies are done at the British Museum of Science.

Indonesia is literally composed of volcanoes. But there is a particularly dangerous “kink” underneath the Strait, as discovered in 1988. It is the geological equivalent of a knot in someone’s stomach.

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