One record stated that 2000 years ago, "Earthquakes in Ninghsia usually come in the spring and winter. When they do, the well water becomes agitated, and the dogs bark, as if to ward off the disaster."
兩千年前，寧夏省就有「寧夏地震，春冬居多，若井水渾濁，寧犬同吠，得防此患」的說法，鄧大量據此製造了「渾濁度儀」，用來測量地震前的井水變化。