ARE SURFACE FAULTS ACTIVATED BY SUBSIDENCE INDUCED BY GROUNDWATER PUMPAGE?

In the 1920's it became apparent that high volume pumpage of shallow water, oil and gas caused ground surface subsidence in the Houston Metropolitan Area. By the late 1960's the subsidence contours extended over most of the metropolitan area, and geologists observed that most known active faults were within the subsidence basin. This led to the notion that groundwater pumpage also activated previously dormant faults. That notion has become so deeply entrenched that many accept it for fact, and even begin to assume that present controls on pumpage will render the faults inactive. This presentation challenges that notion on grounds that it: 1) fails to account for active faults located where insignificant groundwater is produced in insignificant amounts; 2) fails to account for fault activity prior to man's residence in the Gulf Coastal Plain; 3) is not based on a formal, testable scientific theory for the mechanism of faulting; 4) is not in accord with the firmly established principle of effective stress, which, over 7 decades, has been proven repeatedly in laboratory and field experiments; 5) attributes movements on faults that extend to depths over 20,000 feet to soil compaction at depths less than 2000 feet.

Data from fault displacement monitoring over the past 18 years provide additional concerns that the mechanism of fault movement cannot be attributed to a single, simple process.