Quote from above “A geophone works by translating ground movement into voltage, which can easily be read by a microcontroller”
Please SF provide a schematic “application circuit” to interface your Geophone to an Arduino! It is not that simple to hookup to the Arduino A/D input. You probably need a precision OPA (24 bit) and some low pass cut off filters.
http://arduino.cc/forum/index.php?topic=73149.0