DETECTION OF SUBSURFACE CAVITIES

Abstract

RESEARCH HAS BEEN IN PROGRESS SINCE JULY 1970 TO DETERMINE WHICH GEOPHYSICAL AND REMOTE-SENSING METHODS OFFER THE MOST PROMISING RESULTS FOR DETECTING SUBSURFACE CAVITIES AND WHAT MIGHT BE DONE TO FURTHER DEVELOP THEM. THROUGH EXTENSIVE FIELD TESTS, IT HAS BEEN DETERMINED THAT NONE OF THE STANDARD ELECTRICAL RESISTIVITY PROCEDURES GIVE CONSISTENTLY GOOD RESULTS. AS A RESULT OF THE INITIAL FIELD TESTING, A NEW PROCESS OF DATA INTERPRETATION HAS BEEN DEVELOPED FOR ONE SPECIFIC ELECTRODE CONFIGURATION. CAVITIES LESS THAN 10 FEET IN DIAMETER AND AT DEPTHS GREATER THAN 100 FEET WERE LOCATED. RESEARCH IS CONTINUING TO ADAPT THIS PROCESS FOR LOCATING WATER- OR MUD-FILLED CAVITIES.