Is it normal for the geophone to sound like something is loose?


I received my RS 4D yesterday. Is it normal for the geophone to sound like something is loose inside? I haven’t powered it up yet.


The noise you are hearing is the sensitive mass in the geophone. It is that mass that “remains motionless” as the earth moves and generates electric signals that become your seismic signal.

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Thanks @OBSeismo. @kerniew This might be of interest to you as well!:



Great! Thanks much. I was afraid that it had been broken during shipping.


Oh no chance, those geophone are tough!

Have fun Shaking



Absolutely, we are having fun shaking here in Ridgecrest, California.

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I found a great description of a seismometer from the 1970 paper on the Lunar Passive Seismic Experiment (Apollo 11 and 12):

Passive Seismic Experiment
Gary V Latham, Maurice Ewing, Frank Press, George Sutton, James Dorman, Yosio Nakamura, Nafi Toksoz, Ralph W iggins and Robert Kooache

“A seismometer consists simply of a mass free to move in one direction that is suspended by means of a spring or a combination of springs and hinges from a framework The suspended mass is provided with damping to suppress vibrations at the natural frequency of the system The framework rests on the surface whose motions are to be studied and moves with the surface The suspended mass tends to remain fixed in space because of its own inertia while the frame moves around the mass The resulting relative motion between the mass and the frame can be recorded and used to calculate original ground motion if the instrumental constants are known.”

Science, 167 (3918), 455-457