|21 October 2003
Catastrophes formed Alaska
Rather than a slow shaping over the countless eons of geological time, Alaska has been repeatedly blown apart by cataclysmic jolts that have had immediate and profound effects on the landscape and its inhabitants. Alaskan catastrophes provided examples and the subject matter of a number of papers presented at a conference called to discuss the continuing impact of extreme events on lives, landscape and planning. ‘Extreme Events: Understanding Perturbations to the Physical and Biological Environment’ was sponsored by the Arctic Division of the American Association for the Advancement of Science and inspired by the 7.9 quake that struck three Alaskan faults in November 2002, causing the biggest slip-strike earthquake in North America for 150 years. The quake produced more change in the landscape in 100 seconds than would have occurred through 1,000 years of geological slip.
The conference, in Fairbanks, was attended by hundreds of geologists biologists, glaciologists, volcanologists, anthropologists and climate modellers. Explaining the background to the conference, volcanologist John Eichelberger argued that discoveries in the 1960s revolutionised scientific thinking about the way catastrophes have changed the world. Previously, scientists had tended to dismiss the notion that the Earth was molded by sudden extreme events as the product of superstition and religion. Earth was thought to have evolved through gradual processes that could be measured, tracked and projected into past or future. But realisation of the role of tectonic plates, and the discovery of the six-mile-wide impact crater on the Yucatan Peninsula, produced a fundamental shift in the scientific world view.
Alaska “is definitely where the action is” says Eichenberger, citing earthquakes, volcanic eruptions, landslides, tsunamis, floods and fires and the impact of human agency – disease epidemics, the detonation of hydrogen bombs close to tectonic faults, oil spills at sea and global warming. Examples were the five colossal volcanic explosions that occurred during the last 10,000 years. One eruption, in 1400 BCE, created the 6-mile-wide Aniachak caldera and pulverised 17 cubic miles of rock, covering the Alaskan peninsula along Bristol Bay with 45 feet of ash. The resulting 120-mile biological dead zone may have been the major factor in separating Aleut and Eskimo cultures.
Still at human scale, in 300 BCE a large earthquake dropped the western Alaskan Peninsula by nine to 15 feet, altering the lives of the ancient Aleuts to a degree difficult to imagine today. Archaeology has revealed intricate carvings suggesting a shamanistic culture centred on the sockeye salmon, the primary resource upon which villages and social structure was based. The quake led to the complete inundation and destruction of almost every sockeye salmon lake on the peninsula, according to one of several anthropological reports describing how disasters have repeatedly wrecked the lives of Alaskan people.
More about the Extreme Events conference can be found at arctic.aaas.org/meetings/2003/
Source: Anchorage Daily News (13 October 2003)
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