Seismic Microphone as C/V source

[Echophazer at aol.com]

Hello,
 Seeing this post reminded me that I had picked up a seismic microphone at a 
local surplus store awhile back. 

On it is listed: 
14 Hz  335 Ohm 

I would like to build a circuit that would allow me to output an increasing 
control voltage as the magnitude of a seismic event increases. I have a few 
ideas already of what I'd like to do with the finished circuit but I need 
help in designing one. If anyone has any ideas I could try I would be very 
grateful. 

All the best,
Peter B.