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60 years of ground deformation analysis at Kīlauea volcano using geodetic measurements and air photos correlation

Stefano Mannini1,2, Joël Ruch2, Steven Lundblad3, Nicolas Oestreicher1,4,5, Richard Hazlett3, Ingrid Johanson6

  • Affiliations:  1Department of Earth Sciences, University of Geneva, Geneva, Switzerland; 2ISTE -- Institute of Earth Sciences, University of Lausanne, Geopolis 3793, 1015, Lausanne, Switzerland; 3Department of Geology, University of Hawai'i at Hilo, Hilo, HI 96720, USA; 4WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland; 5Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland; 6U.S. Geological Survey, Hawaiian Volcano Observatory, Hilo, HI 96720, USA 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 120

  • Programme No: 3.15.25

  • Theme 3 > Session 15

Abstract

Normal faults, extensional fractures and grabens are common features observed at basaltic volcanic islands. They are often associated with volcano-tectonic events such as magma propagation and earthquakes. Here, we analyse the case of the Koa'e fault system, part of the Kīlauea volcano, Hawaii.  Magmatic intrusions propagate along two volcanic rift zones, the Southwest and the East Rift Zone, respectively. However, sometimes magma finds barrier and intrudes into the Koa'e fault system (e.g. 1973, 2018 or 2024 event). These intrusions and other volcano-tectonic events cause ground displacement and reactivate specific portions of the fault system. Although this area is monitored by scientists since 1966, we lack a continuous ground deformation analysis over the entire period. Thus, we aim to combine different geodetic methods at different temporal and spatial scale to highlight the fault reactivation during the last 60 years.  In the 1965, scientists from the Hawaiian Volcano Observatory installed different benchmarks to survey regularly and monitor the deformation in the Koa'e area using geodetic techniques. Over time, with the advent of satellites, new methods have been developed and continue to advance research striving to achieve more complementary methods. Results show evidence of fault reactivation during four periods, 1973, 1975, 2018 and 2024. We observed different phases of compression and extension at normal faults and propose a simple structural model to explain these deformation types. These evidence reveal important understanding about fault reactivation and fault processes during volcano-tectonic events that involve long-term instability with short term dike intrusions and fault motion.