Lithological heterogeneities below the Kīlauea caldera before its 2018 collapse inferred from ground magnetic anomalies - Dataset
Organisation : Observatoire de Physique du Globe de Clermont-Ferrand
Licence : Creative Commons Attribution
Mots-clés : dataset,forward-and-inverse-modeling,geology,hydrothermal-alteration,magnetic-anomalies,volcanism,volcano-tectonic-inheritance,weakness-structures

The 2018 crisis of Kīlauea volcano stands as a major event in its evolution with a large down-rift effusive eruption that drained a shallow magma reservoir at the summit. The characterization of such active magmatic systems and associated hazardous events remains a necessity and a challenge. The summit area is hydrothermally active and strongly altered as indicated by geological mapping. A unique dataset of geophysical measurements was collected around Halemaʻumaʻu crater before its collapse. Magnetic data are interpreted here in combination with geological information, temperature anomalies at the surface, self-potential measurements, and a model of electrical conductivity. 3D forward models show that the main magnetic dipole-like anomaly observed around the crater is not only caused by the crater topography but suggest the presence of an important volume of weakly magnetic material beneath the crater, and which may be caused by higher temperature and/or hydrothermal alteration. 3D inversion of the data allows us to explore the first order geometry of the magnetic structures. We complemented it with 2D forward modeling in order to refine the geometry of major structures. The 2018 collapsed area was thus lithologically heterogeneous with several major mechanical contrasts that likely played a role in the geometry of the collapse. Therefore, mapping magnetic anomalies and monitoring their temporal evolution are of great interest for constraining the nature and mechanical properties of the underlying formations and their evolution in order to help predict future behavior.

How to cite:
Gailler, L.-S., Bouligand, C., Kauahikaua, J., Lénat, J.-F., & Cluzel, N. (2023). Lithological heterogeneities below the Kīlauea caldera before its 2018 collapse inferred from ground magnetic anomalies [Data set]. OPGC, LMV. https://doi.org/10.25519/6W2G-DR94