PSN-L Email List Message

Subject: Re: clock pendulums
From: Bill S wls@.........
Date: Tue, 15 Mar 2011 17:01:33 -0400


On October 16, 1999 I recorded the California " Hector Mine Earthquake" 
on a precision clock I was running in New Jersey using Bryan's Microset 
timer. Bryan kindly posted the Microset image on his site. I've provided 
a link here.

http://www.billtime.com/penpics/fedquake.JPG

What he said on his site at that time in 1999.

/"I was pretty pleased with myself after having recorded this earthquake 
in my pendulum. But later in the day I got an email from someone with a 
much bigger tale to tell. Bill Scolnik is an horologist who lives in New 
Jersey. Bill has collected some of the most precision pendulum clocks 
ever made. One of his most accurate clocks was made by the Russian F.M. 
Fedchenko. This clock is run in a vacuum tank, in a specially 
constructed temperature controlled room, and is mounted to a massive 
slab of concrete that rests on resilient pads set in a hole in the 
ground to isolate it from outside influences. Bill often records the 
performance of his Fedchenko with the MicroSet timer and the "GPS 
interface" with a rubidium reference. He happened to be recording his 
Fedchenko on the morning of October 16. Later that day he was working on 
the clock and noticed a small irregularity in his data. Close 
examination revealed that his precision Fedchenko pendulum had been 
disturbed by the earthquake in California 2,000 miles away!/

/The graph below shows Bill's data. The clock was running a tiny bit 
fast (2.1 seconds per month) but was generally flat. At about 6:04 AM, 
18 minutes after it shook southern California, the earthquake rolled 
through eastern New Jersey and jostled Bill's pendulum. The disturbance 
is clearly visible in the MicroSet graph.
/

/I suppose this should not surprise us. Scientists have long used 
precision pendulums to measure gravity and we know that the most 
accurate pendulums will change rate subtly when the moon passes 
overhead. Still, it's rather impressive to see a pendulum clock respond 
to an earthquake so far away."
/


  
    
  
  
    

On October 16, 1999 I recorded the California " Hector Mine Earthquake" on a precision clock I was running in New Jersey using Bryan's Microset timer. Bryan kindly posted the Microset image on his site. I've provided a link here.

http://www.billtime.com/penpics/fedquake.JPG

What he said on his site at that time in 1999.

"I was pretty pleased with myself after having recorded this earthquake in my pendulum. But later in the day I got an email from someone with a much bigger tale to tell. Bill Scolnik is an horologist who lives in New Jersey. Bill has collected some of the most precision pendulum clocks ever made. One of his most accurate clocks was made by the Russian F.M. Fedchenko. This clock is run in a vacuum tank, in a specially constructed temperature controlled room, and is mounted to a massive slab of concrete that rests on resilient pads set in a hole in the ground to isolate it from outside influences. Bill often records the performance of his Fedchenko with the MicroSet timer and the "GPS interface" with a rubidium reference. He happened to be recording his Fedchenko on the morning of October 16. Later that day he was working on the clock and noticed a small irregularity in his data. Close examination revealed that his precision Fedchenko pendulum had been disturbed by the earthquake in California 2,000 miles away!

The graph below shows Bill's data. The clock was running a tiny bit fast (2.1 seconds per month) but was generally flat. At about 6:04 AM, 18 minutes after it shook southern California, the earthquake rolled through eastern New Jersey and jostled Bill's pendulum. The disturbance is clearly visible in the MicroSet graph.

I suppose this should not surprise us. Scientists have long used precision pendulums to measure gravity and we know that the most accurate pendulums will change rate subtly when the moon passes overhead. Still, it's rather impressive to see a pendulum clock respond to an earthquake so far away."


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