Examples from the Web for geophone
"The vibrodyne machine isn't running," he remarked finally after repeated adjustments of the geophone.
The geophone expert was at his bedside, waiting impatiently.
There was a tense five minutes as the geophone expert listened.
The first geophone used by the western powers in the war was invented by the French.America's Munitions 1917-1918|Benedict Crowell
Nothing at all of any value was being recorded by the geophone when Kennedy glanced quickly at his watch.