Yang lebih menakutkan justru malah gunung api. dimana Indonesia ini merupakan 1/3 ring of fire (rentetan gunung api di Asia Pasific) Toba, Sumatra meletus 73 000 tahun lalu, padahal siklus gunung meletus besar biasanya setiap 50 000 sedang impact meteor tiap 100 000 tahun sekali.
Kayaknya manusia ini sukanya mencari penyebab dari luar. Padahal kemungkinan "threat" lebih banyak ya dari dalam bumi sendiri. Yang mambahayakan kita .... ya kita sendiri kali ya ... rdp ================= Volcanos a bigger threat than comets A volcanic super-eruption could pose twice as much of a threat to civilisation as a collision with an asteroid or comet. Every 100,000 years, a cosmic body with a diameter of more than one kilometre slams into the Earth but Michael Rampino, of New York University, warned that a massive volcanic eruption capable of causing as much devastation occurs once every 50,000 years. "Volcanoes in Yellowstone Park and Long Valley in California have erupted three times in the past 1 million years, each time coating the whole of the US with ash," New Scientist magazine said. "But the biggest and most recent super-eruption happened at Toba, on the island of Sumatra, 73,000 years ago." According to Mr Rampino's research, Toba blasted a crater 100 kilometre long and sent 3 billion tonnes of sulphur dioxide into the atmosphere and a dense volcanic cloud around the globe. "He also suspects that Toba's super-eruption was responsible for the population crash of 70,000 years ago, when the number of people fell to no more than 10,000," the magazine added. Ash and aerosols from super-eruptions block the sun and send global temperatures plummeting. Another Toba super-eruption could push temperatures down and cause regional cooling, according to Mr Rampino. "That's going to kill off most of the above-ground vegetation in Africa," he said, adding global vegetation could be reduced by 25 per cent. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] Visit IAGI Website: http://iagi.or.id IAGI-net Archive 1: http://www.mail-archive.com/iagi-net%40iagi.or.id/ IAGI-net Archive 2: http://groups.yahoo.com/group/iagi ===================================================================== Indonesian Association of Geologists [IAGI] - 31st Annual Convention September 30 - October2, 2002 - Shangri La Hotel, SURABAYA
