ABQ More on the Asian Tsunami 26 September 2005
It is officially known as the Sumatra-Andaman earthquake.
It seems from New Scientist edition 2501
dated 28 May 2005 page 10, that it was indeed a truly devastating event.
The Magnitude 9.15 was the highest number that I can recall. (The scale is
logarithmic and every increase of one number is an energy release of ten
times). Every spot on the surface of the globe moved by at least one
centimetre, although the seismic wave moved so slowly that it was imperceptible
in most places. "Every human took a ride on the wave"
Most earthquakes last only a few seconds, but the Sumatra-Andaman quake shook the ground violently for nearly ten minutes. For a given distance from the epi-centre of the quake the ground shook at least a hundred times more than during the 1994 Northridge earthquake in the Los Angeles area, or the San Francisco Bay area's Loma Prieta quake in 1989. Also unprecedented was the 1300-kilometre length of the rupture along the boundary of the Indo-Australian and south-eastern Eurasian tectonic plates. It was totally unpredictable said Charles Ammon of Pennsylvania State University.
The deductions were made from instruments in Japan and Germany, plus GPS readings of ground movements. Even as the Asian quake was unfolding it triggered the most distant small quakes ever detected: 11,000 kilometres away in Alaska, the Mount Wrangell volcanic area was shaken by fourteen tiny quakes in just eleven minutes that came precisely in sync with every passing pulse of the large earthquake, according to Michael West of the University of Alaska at Fairbanks (Science vol 308 p 1144).
A month after the main event there was an astonishing cluster of 150 quakes of magnitude 5 or greater in the Andaman area -- the most energetic cluster of earthquakes ever observed on Earth. The oscillations are still going on. It is reported that a distinctive vibration frequency left over from the 26 December quake was still detectable last week (now being May 2005) moving the ground by about half a micrometre. "It should remain detectable for a couple more months." says Park. "The earth is still ringing".
CDC comment When a bell is struck it will oscillate for a number of minutes before the movements of the metal are too small to detect. The movement that causes the air to vibrate, and is detected as an audible noise, will only last for a few seconds. The earth is a lot heavier than a bell, but it follows the same laws of motion and will ring in a similar manner. But the frequency of the oscillation is far below that that will cause an audible noise. The inertia of the material that the earth is made of will also make the ringing last very much longer than that of a bell.
In my opinion, there will be no intelligent life left on earth when the planet has finally settled to a quietitude. It is still very young and bubbling beneath our feet. Read my yarn on mankind leaving the earth (yet to be posted).