Geothermal characteristics of the Paolai hot spring area, Taiwan

Abstract

In order to understand the geothermal potential of Paolai Hot Spring area, we conducted extensive geological surveys, collected seismic data, and analyzed geochemistry of hot springs in this region. Two hydrological circulation models are assessed here that are based on previous campaigns and studies: 1) the single fault (the reverse Chaozhou Fault) model and 2) a dual fault model considering the reverse Meilunshan Fault as an additional regional rupture zone. In the single fault model, the Chaozhou Fault serves as the controlling boundary with groundwater replenished from the eastern mountainous area and circulating downward into the subsurface and heated. The deeply circulated hot fluid would be directed upward along the highly ruptured, permeable zone within the fault system. In the dual fault model, the Chaozhou and Meilunshan Faults compartmentalize the hydrological circulation into two systems. To the east of the Meilunshan Fault, groundwater is replenished from the
mountainous area, circulating downward, heated, and migratesto the surface along the open fissures on the hanging wall of the Meilunshan Fault to form hot springs. The western compartment would be controlled by the Chaozhou Fault. Our field results concur the occurrence of the Meilunshan Fault while the seismic and geochemical data also suggest distinct characteristics across the fault. To better evaluate the geothermal potential in Paolai area, further investigation towards the complex structures in this region should be thoroughly considered.