From: Stephen & Kathy skmort@............

Date: Sun, 25 Mar 2007 15:42:25 -0700

Calc. Problem #1 On my AS-1, it shows a P to P count of 147.48 with a period of 3.6 seconds for the P wave of the 7.2 Vanuatu quake on 3 March 07! I divide by 3.6 to get a one second count of approx. 41. Later, another event from Vanuatu gives me a count of 90.58 at 4.5 seconds,, which converts to a count of about 20. Assuming that the converted one second counts are proportional to ground motion, and that the second event produced about half, I found the log of .5 = about -.3,, summed to 7.2 = approx. 6.9 for an approx. mag for the second event!! distance and depth are about the same, is the distance to great for this kind of relative calculation? I'm about 6080 miles from the two events! Calc. Problem #2 Using the USGS quake distance calculator I find that my estimated one second ground motion for the 7.2 Vanuatu quake would be 1.4 micro meters! On my AS-1, 225 counts = one volt! Can I assume 41 / 1.4 = approx 29 count per micro meter per second = .13 volts per micro meter per second sensitivity????? (or convert to proper terminology????) and or does 2pi enter in somewhere??? I see the 2pi factor in the USGS calculator from micro meter to micro meter per sec? (.13 * 2pi = .82 v / micro meter / s) Any tutoring on my overly simple process, and or assumptions are welcome!!! Please make it as simple as possible, thanks. Stephen PSN Station #55 38.828N 120.979WCalc. Problem #1

On my AS-1, it shows a P to P count of 147.48 with a period of 3.6 seconds for the P wave of the 7.2 Vanuatu quake on 3 March 07! I divide by 3.6 to get a one second count of approx. 41.

Later, another event from Vanuatu gives me a count of 90.58 at 4.5 seconds,, which converts to a count of about 20.

Assuming that the converted one second counts are proportional to ground motion, and that the second event produced about half, I found the log of .5 = about -.3,, summed to 7.2 = approx. 6.9 for an approx. mag for the second event!! distance and depth are about the same, is the distance to great for this kind of relative calculation?

I'm about 6080 miles from the two events!

Calc. Problem #2

Using the USGS quake distance calculator I find that my estimated one second ground motion for the 7.2 Vanuatu quake would be 1.4 micro meters!

On my AS-1, 225 counts = one volt! Can I assume 41 / 1.4 = approx 29 count per micro meter per second = .13 volts per micro meter per second sensitivity????? (or convert to proper terminology????) and or does 2pi enter in somewhere??? I see the 2pi factor in the USGS calculator from micro meter to micro meter per sec? (.13 * 2pi = .82 v / micro meter / s)

Any tutoring on my overly simple process, and or assumptions are welcome!!!

Please make it as simple as possible, thanks.

Stephen

PSN Station #55

38.828N 120.979W