A seismic monitoring station in a neighborhood (Upper Ringwood, NJ) that is prone to dangerous sinkholes. The neighborhood sits above a netwok of fomer iron mines which were filled by toxic waste by Ford Motor Company in the 1960's and 70's. Now, with Ford removing the toxic sludge from the mine shafts (it is a Superfund site) there have been sinkholes created that have threatened homes in the area.