Testing Volcano Deformation Models Against 3D Seismic Reflection Imagery of Ancient Intrusions
Year: 2026
Type: article
Abstract: Magma intrusion often drives uplift of the overburden and free surface. Analytical modeling of such surface uplift at active volcanoes allows us to estimate intrusion geometries and positions, as well as volume and pressure changes; these insights have proven critical to forecasting volcanic unrest and eruptions. However, it is rarely possible to compare geodetic source parameters retrieved from analytical models to known intrusion geometries. Seismic reflection data offer an opportunity to image and quantify ancient, buried intrusion geometries and their overburden deformation (i.e., a forced fold). Here, we use 3D seismic reflection data offshore NW Australia to investigate an Early Cretaceous forced fold developed above a laccolith emplaced at ∼0.6–1 km depth. We remove the effects of post‐emplacement, burial‐related compaction and estimate surface displacement patterns for the forced fold. Analytical modeling of these surface displacements, using both thin plate bending and elastic half‐space solutions, suggest source (intrusion) estimates of position and lateral dimensions are similar to those of the actual laccolith. There are some differences between measurements of the laccolith and modeled source estimates, which we attribute to syn‐intrusion space‐making mechanisms (e.g., compaction). We particularly find penny shaped crack and rectangular dislocation elastic half‐space solutions underestimate source emplacement depth by ∼0.2–0.9 km, probably reflecting a lack of heterogeneity (layering) in our models. Our novel approach highlights seismic reflection data is a powerful tool for understanding and testing how magma emplacement translates into surface deformation at active volcanoes.
DOI: 10.1029/2025jb032007
Authors: C. Magee, S. K. Ebmeier, J. Hickey
Institutions: University of Leeds, University of Exeter
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,070
OpenAlex ID: W7127968118