| Title | Favorable Structural Settings of Geothermal Systems in Active Tectonic Regions: A Global Perspective |
|---|---|
| Authors | James E. Faulds, Nicholas H. Hinz, Mary Hannah Giddens, Natalie Wigger, Isabelle Chambefort, Mark |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Favorable structural settings (FSS) control many higher temperature geothermal systems in active tectonic settings, including the Basin and Range province (western USA), western Turkey, East African rift, Taupo volcanic zone (New Zealand), many volcanic arcs, and elsewhere. They include various fault interaction zones, such as terminations, step-overs (relay ramps), and accommodation zones in extensional settings, pull-aparts and displacement transfer zones in transtensional domains, and fault intersections in collisional orogens. FSS are characterized by structural complexity, closely-spaced faults, and greater proportions of fault breccia vs. fault gouge, which enhance permeability and facilitate fluid flow. Identifying FSS is an important exploration tool used successfully in some regions to locate hidden geothermal systems. However, FSS are common, with only a fraction likely hosting a hidden system. Identifying FSS and assessing their geothermal potential requires integration of multiple geological and geophysical datasets. In most areas, this process is difficult to automate due to lack of high-resolution lidar, detailed geological maps, and detailed geophysical surveys. Further, many FSS (e.g. fault tips) are characterized by minor faults with minimal surface ruptures, making them difficult to recognize. Nonetheless, FSS can be ranked subjectively based on structural complexity, as well as more quantitatively based on slip rates, slip/dilation tendency, and recency of faulting. Where detailed geophysical surveys exist, terminating and intersecting gravity gradients and low resistivity anomalies can also be used to rank FSS. Analysis of the most conducive geometries for known geothermal activity for individual FSS types can also be employed to assess FSS for hidden systems. |