EGU24-11626, updated on 09 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Uncovering Lāna’i's hidden heat: geophysical insights on the subsurface hydrothermal activity of this Hawaiian island 

Xavier Bolós1, Nicole Lautze2, Mario Boijseauneau3,4, and Mattox Telwar2
Xavier Bolós et al.
  • 1Geosciences Barcelona (GEO3BCN), CSIC, Lluís Solé i Sabarís s/n, 08028 Barcelona, Spain.
  • 2Hawai’i Groundwater & Geothermal Resource Center, Institute of Geophysics and Planetology, University of Hawaiʻi, 1680 East-West Road, Honolulu, Hawaii 96822, United States of America.
  • 3Posgrado en Ciencias de la Tierra, UNAM, Campus Morelia, 58190, Morelia, Michoacán, México.
  • 4Mineral & GeoData Analytics, Uvas 41, Punta Roma, 58195, Morelia, Michoacán, México.

The Hawaiian Islands, characterized by volcanic activity and complex hydrogeological systems, encounter energy challenges due to reliance on imported fossil fuels. Therefore, exploring geothermal sources is crucial for sustainable development, given the islands' isolation. Simultaneously, understanding freshwater reservoirs is vital for sustainable water resource management. This multidisciplinary study on Lāna’i Island integrates geophysical, groundwater, and mineralogical data, unveiling insights into concealed deep hydrothermal activity and its heat source. Correlations observed in newly acquired self-potential (SP) data combined with earlier gravity and magnetotellurics (MT) data reveal the presence of a hydrothermal upflow, perhaps originating from deep magma reservoirs beneath the Pālāwai caldera. The concealed hydrothermal system emerges as a potential geothermal resource at >2 km depth, requiring further deep drilling research to confirm its presence. In addition, XRD analysis reveals varying degrees of hydrothermal alteration, indicating high temperatures during fluid-rock interactions. The alignment of surface alteration with current upflow zones suggests an active hydrothermal system persists in the caldera faults since the shield-building stage, which causes warm brackish water within the Pālāwai basin. This prompts a discussion about the possible presence of a geothermal resource. This subject has been under investigation for the past seven years as part of the Hawaii Play Fairway project. The impact of hydrothermal activity appears limited to the Pālāwai caldera and the Canyon zone, contrasting with the Munro Trail ridge area, which serves as an independent freshwater source with impounded aquifers. Understanding this convergence of geothermal investigation and freshwater reservoir analysis holds significant importance for fostering sustainability in the Hawaiian archipelago.

How to cite: Bolós, X., Lautze, N., Boijseauneau, M., and Telwar, M.: Uncovering Lāna’i's hidden heat: geophysical insights on the subsurface hydrothermal activity of this Hawaiian island , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11626,, 2024.