[time-nuts] Using oscillators to measure earthquakes
holrum at hotmail.com
Wed Jan 7 02:50:12 EST 2015
Today the Dallas area has been experiencing several eathquakes. The largest were magnitude 3.2, 3.6, and 3.1 at a depth of around 4km. They happened around every three hours. I am around 5 miles from the epicenter. They are strong enough to shake the house quite a bit. The largest put a hairline crack in some sheetrock.
After the second one I cobbled up a sensor using an old "tight pll" type of circuit that I was playing with several years ago, 24 bit A/D, and an AVR based touch-screen microcontroller. I hacked up some quick code to monitor and graph the A/D. Inputs to the circuit were an HP5065 and a rather woogedy 5 MHz OCXO. The oscillator was placed on my garage floor and weighted down with a 2kg calibration weight. Woo hoo! the last quake did produce a measurable signal... Now I have to figure out a way to get the data off the micro-controller...
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