Home Built Seismograph

This project was started on a dare by a friend of mine. We went to a local sale here at work (UC Riverside) which had a bunch of chart recorders. Well, I said that someday I should buy one of them and try building size or seismograph. As it turns out, it was my birthday in my dear friend Paul Lowe bought me one.

Well, now I was committed. I came up with some pretty strange stuff. Wires hanging from the garage, weights everywhere.

It dawned on me the to use the power of the Internet. I got hold of a group through a news site called the PSN. (Public Seismic network). After I did this, tons of information came following down on top of me. This is where I was introduced to a unit called the Lehman.

Being into electronics and lazy at the same time, I did not want to wind a coil and used something called a Hall Effect Transducer.

It worked fairly well with the circuit I built. Going back to the sale on campus again, I was astonished to find 3 PS -1 portable seismographs built by Kinemetrics. I called a friend of mine here at the University and we went over and bought two of them.

Kinemetrics was wonderful and sent me a complete set of instructions on the PS -1. Kudos to them!

Twenty-five dollars apiece! I was in heaven! One small problem was that the drum was missing and that it was setup to use smoked paper.

With a little work and help from my next-door neighbor John Allen, we made new drums out of five inch Plexiglas. The stylis is ink fed now and works great. Jerry Sorrels from here at work found a place that sold low frequency Geo phones. So now I have both a short period and long period system. It has since been outfitted with a coil pickup and has happily picked up quakes from all over the place. Now with the Kinemetrics satellite clocked, I know right when they arrive.

Here you can see the PS-1 on top of my old Stereo cabinet. Underneath is a VCR and a Kinemetrics Satellite clock. I get 12 hours on a paper. The best paper I have found is chart recorder paper. I cut the one end off with a saw. This allows the pen to go over to the end without getting stuck. I put the paper in an old aluminum sheet dispenser and tear off what I need. I also use a glue pen to mount it. I can mount a piece in about 10 seconds.

This is the Lehman that I built. The weight is an old 4" socket used for large equipment. I welded in 2 nuts which thread over the boom's arm. This way I can move the mass in and out easily.

I was using salad oil for damping. I now use hydraulic fluid. My dog was attracted to the salad oil, but has no interest in the hydraulic fluid. The boom now sits under my new addition's stairwell. The weight blocks are just there for added benefit. The round item is a magnetic level indicator.