Application of CSAMT in hydrogeology exploration in Shandong Province - An example from geothermal exploration in Changdao County (south four islands)

The geophysical exploration in Changdao County is conducted using controlled source audio-frequency magnetotelluric (CSAMT) method. The inversion results reveal obvious evidences of one existed fault and five new blind faults, including their location, size, occurrence and development degree. Another two low resistance anomaly zones are delineated. According to the results, a geothermal well drilling test is applied in the middle of South Changshan Island, discovering a large flow of salt hotspring with bromine and strontium. The outlet temperature is 36 °C and the yield of a single well is 1 830 m3/d. This study on island hotspring exploration marks the first of its kind conducted in Shandong Province. It provides basic high-quality information for subsequent similar studies.