Implication of Geothermal Conduits with the Relationship Between Fracture Intensity and Fault Distribution in the Central Mountain Area of Taiwan
Journal
Transactions Geothermal Resources Council
Series/Report No.
Transactions Geothermal Resources Council
Journal Volume
48
Date Issued
2024-01-01
Author(s)
Abstract
In recent years, Taiwan has become actively to develop renewable energy sources and investigate geothermal resources. One area of interest is the Lushan region, known for its numerous hot spring outcrops. Preliminary surveys suggest that it holds potential for geothermal development. Successful geothermal energy development relies on the existence of an enough heat source and appropriate pathways for the heat to rise to shallow depths, and a detailed geological map is a must for effective and cost-efficient exploration. This study bases on the previous geological map covering the western fringe at the middle part of the Central Mountain Range and zooming in the Lushan area with more detailed mapping. While the ongoing Quaternary orogeny in Taiwan has created a unique geological environment and the rapid uplift has brought in abundant heat sources, the compressed slate and meta-sandstone formations have resulted in complex subsurface structures, and the rugged mountain ranges and deep valleys also prevent a thorough geological field work. Finding additional and creative methods to build more precise geological map in such a challenging area for interpreting underground rock types and structures has become a pressing need. Our approach is to gather data from field survey works, digital elevation model (DEM), and previous literatures for exploring various geological structure patterns, then fracture network analysis is executed to categorize those data for the fracture strength map. Five factors, including outcrop fracture density, rock porosity, outcrop fracture intensity, outcrop fracture connectivity, and surface lineament intensity, are determined for the analytical process. The normalized score from each factor is calculated and assigned into grid map for the final fracture strength index. The existence and trend of projected fault zones and other structural features are confirmed by comparison with the fracture strength index map in the Lushan area. Our integrated results strongly indicate the important value of digital processing, which is not only capable of consistently describing outcrop information, but also effectively complements field surveys in a remote area. Through the fracture strength index map, this study also implies the potential areas of the geothermal reservoir and hot fluid conduits, providing valuable information for geothermal exploration.
Subjects
Fracture intensity
Geological map
Geothermal conduits
Structural features
SDGs
Type
conference paper