## 3 Results and Analysis
### Geological Structure Characteristics of Zhongtang and Wentang Hotsprings
#### 3.2.4 Geological Characteristics of Shentang Geothermal Field
There is a structural fracture zone inclined northward along the profile at the depth of 420 m. The Cagniard resistivity is 400 \(\Omega\)\(\cdot\)m. The zone is supposed to be a structural fracture zone, but the resistivity is high, and the water content is small. Figure 11: Jc1 apparent resistivity profile of Shentang geothermal field. 2. Resistivity Characteristics There were three multi-electrode resistivity lines in Shentang field (W5, W6, W7; Figure 3). The profiles with anomalies in W5 line mainly included Profile 3 (P3) and Profile 4 (P4). P3 was 300 m long, with a point distance 2.5 m. There were 120 measuring points in total. As shown in Figure 13, there is a steep low resistivity layer with resistivity less than 52.9 \(\Omega\)-m below the depth of 50 m in the 120-160 m interval on the right side of W5. The low resistivity layer is inferred to be a water-bearing fracture zone. In the 200-300 m interval below the depth of about 30 m there is another low resistivity layer which is inferred to be shale. The parameters of P4 such as the length, the point distance, and the total measured points were same with P3. As shown in Figure 14, P4 coincides with some areas of P3, which proves that there is indeed a structural fracture zone on the right side of P4. The strata structure of P4 correspond to that of P3; both of them are sandy pebbles with high resistivity in the upper stratum, there are rock stratum with low resistivity in the middle part and completed stratum with high resistivity in the lower part. The two profiles P3 and P4 can verify each other. Figure 12: Jc2 apparent resistivity profile of Shentang geothermal field. The profile with anomalies in W6 line was Profile 1 (P1). P1 was 300 m long, with a point distance 2.5 m. There were 120 measuring points in total. Figure 15 shows the same strata of W6 line as those of W5 line, the structural fracture zone is obvious, and the stratum is the steepest in the 160 m area of the line. Comparing the analysis of W5 and W6 lines with geological map, it could be inferred that F1 fault fracture zone is located right in the steep area of structural fracture zone in P3 and P4 of W5 line and the structural fracture zone in P1 in the 160 m area of W6 line. The profiles with anomalies in W7 line was Profile 2 (P2). P2 was 300 m long, with a point distance 2.5 m. There were 120 measuring points in total. As shown in Figure 16, P2 shows the same strata as W5 and W6, and the structural fracture zone is obvious. In the 80-150 m interval of W7, the structure is developed, and generally the resistivity is less than 53.4 \(\Omega\)-m. Combined with the geological map, it is inferred that the structure may be the east extension of the Checun-Xiatang fault. According to W5, W6, and W7 analysis, the structural fracture zone in W5 and W6 is the NW F1 fault. In P2 of W7, the inferred fault is Checun-Xiatang fault. Figure 14: Profile 4 of W5 line in Shentang geothermal field. Figure 13: Profile 3 of W5 line in Shentang geothermal field. Figure 15: Profile 1 of W6 line in Shentang geothermal field. 3. Polarizability Characteristics  
A polarizability profile was completed in Shentang geothermal field. As shown in Figure 17, there is a polarizability anomaly at a depth of about 350 m in Shentang geothermal field, indicating that the geological body at this depth has a large polarizability and may be a better water storage stratum. When the line drops below the depth of 500 m, the polarization curve becomes relatively scattered, and it is not obvious of the polarization in deep strata. Therefore, the polarizability cannot accurately measure the geoelectric anomaly, so it is not recommended as the judgment standard. Figure 16: Profile 2 of W7 line in Shentang geothermal field. Figure 17: Polarization profile in Shentang field. Geological Drilling and Pumping Test  
According to the above geophysical results, a hole with a depth of 300 m was located and drilled in the south of Shentang hotspring.