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Tsunami-Triggering-Earthquake Shook Entire Planet
Iphtashu Fitz writes "The earthquake that triggered last years tsunami was the largest one recorded in 40 years and kept the planet shaking for weeks according to new reports that are due to be released on Friday. This was the largest earthquake measured so far by a new worldwide array of digital seismic instruments, whose results will appear in six different reports being published in the journal Science tomorrow. The quake broke several records, including the longest fault line (720 to 780 miles) and longest duration (10 minutes). The water displaced by the rise of the sea floor in the quake zone also resulted in a rise of worldwide sea levels of 0.004 inch. In Sri Lanka, more than 1,000 miles from the epicenter, the ground moved nearly 4 inches. As many as 14 smaller quakes were triggered in Alaska when the tremors from this quake reached the northernmost U.S. state."
The rupture spread from south to north, resulting in a Doppler effect in instruments measuring it. Seismometers in Russia recorded the quake at a higher frequency because it was moving toward them, while those in Australia measured a lower frequency as it moved away.
I was wondering about this: Depending where you are measuring the signal, you should observe different frequencies. Science paper doesn't give too much details about this though.
Link to the Science article. Article has some interesting numbers as well:
It released 4.3 x 1018 J, equivalent to a 100-gigaton bomb, or about as much energy as is used in the United States in 6 months. Shifts in the sea floor displaced more than 30 km3 of seawater, generating a tsunami that traveled to the Antarctic, the east and west coasts of the Americas, and (with lessening amplitudes) the Arctic Ocean.