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Insights from finite-element models into the origin of the Hilina Slump at Kilauea volcano (Hawaii, USA)

The offshore flank of Kilauea volcano (Hawaii, USA) is mobile, experiencing both earthquakes and intermittent landslides. A basal décollement underlies the entire mobile flank on which seaward movement occurs due to the gravitational loading and lateral push of the magmatic plumbing system. The Hilina Slump rides on top of the mobile flank, and the structures bounding the Hilina Slump activate concurrently with large earthquakes. The Midslope Basin is also located on the mobile flank northeast of the Hilina Slump and was likely formed by an ancient landslide, whereas the easternmost part of the mobile flank appears to be unaffected by landslide activity. We created two-dimensional finite-element models to understand why the Hilina Slump formed in its present location and why the eastern part of the mobile flank remains intact. The preliminary results show that movement of the mobile flank along the basal décollement leads to the formation of shear zones within the flank, suggesting that the Hilina Slump formed in response to long-term flank mobility. The implications for the current stability of the Hilina Slump are subject of further investigations. Ongoing research will include direct shear experiments on samples collected from the submarine flank of Kilauea to investigate the mechanical properties of the mobile flank and inform the finite-element models.

Details

Author
Fiene Matthies1, Julia K. Morgan2, Matt J. Ikari3, Morelia Urlaub1
Institutionen
1GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Germany; 2Rice University, Department of Earth Science, Houston, United States; 3Marum – Zentrum für Marine Umweltwissenschaften der Universität Bremen, Germany
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/ce3y-re52
Geolocation
Hawaii, USA