High-resolution monitoring techniques for fault reactivation during the 2024 Kīlauea Southwest Rift Zone eruption

Kīlauea volcano, on the Island of Hawaiʻi, is one of the most active volcanoes on Earth.  Eruptive activity alternates between the summit caldera and two rift zones, to the east and southwest. On June 3, 2024, Kīlauea experienced its first eruption along the Southwest Rift Zone (SWRZ) in 50 years. This brief eruption was preceded by multiple seismic swarms, some associated with dike intrusions, that started in November 2023. These dikes did not reach the surface but reactivated pre-existing faults and generated new structures, reshaping the rift’s near-surface deformation patterns.
To quantify these surface changes, we used high-resolution topographic datasets derived from our helicopter photogrammetry surveys conducted in April 2022 and September 2024. These campaigns produced centimeter-scale DEMs (~8 cm) and orthomosaics (~4 cm), enabling detailed mapping of newly formed fractures, vertical offsets, and extensional opening across the ~12 × 2 km study area. To expand spatial coverage and better constrain multi-year deformation patterns, we complemented these products with airborne LiDAR acquisitions from missions in July 2019 and September 2024. The integration of these multi-temporal topographic datasets reveals the subtle and rapid morphological changes associated with magma intrusion and fault reactivation.
To better understand the kinematics of fault reactivation and magma propagation, we integrated these structural observations with seismic data recorded before, during, and after the June 2024 eruption. This approach reveals the along-rift migration of magma from the summit reservoir, its interaction with pre-existing faults, and the formation of new surface structures. Our analyses highlight the role of flank instability in controlling both rift dynamics and surface faulting during the eruptive episode.
By merging LiDAR, photogrammetry, InSAR, and seismic datasets, this study demonstrates a multi-method approach for capturing near-field deformation with unprecedented detail. Our analysis provides new insights into the mechanics of magma-driven faulting, the propagation of eruptive activity along rift zones, and the interplay between shallow and deep processes. These results not only enhance the fundamental understanding of volcanic rifting dynamics but also inform the development of more accurate hazard monitoring and forecasting models, offering practical applications for risk assessment and mitigation at Kīlauea and similar rift-controlled volcanic systems worldwide.
This study illustrates how integrating multi-temporal, high-resolution geospatial datasets with geophysical observations can advance both scientific knowledge and hazard management strategies. Our approach provides a framework for future eruptions, enabling rapid detection of surface deformation, tracking of magma pathways, and improved preparedness for volcanic crises.