EGU General Assembly 2020
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Mechanical interactions between pressure sources and rift zones at Kilauea Volcano, Hawaii.

Fabio Pulvirenti1, Marco Aloisi2, Daniele Carbone2, Michael Poland3, and Sergio Vinciguerra4
Fabio Pulvirenti et al.
  • 1NASA-JPL, Pasadena, USA (
  • 2INGV Osservatorio Etneo, Sezione di Catania, Catania, Italy (,
  • 3Cascades Volcano Observatory, Vancouver, USA (
  • 4Department of Earth Science, University of Turin, Turin, Italy (

Underground pressure sources and rift zones may act jointly during phases of volcanic activity. Pressurization of magma bodies at shallow to intermediate depth, along with degradation of the mechanical properties of the host rock, can enhance tensile stress along zones of weakness, thus favoring magma intrusion. Such interactions were hypothesized at different volcanoes, including Mt. Etna, Piton de la Fournaise and Montserrat, from seismic, gravity and ground deformation data. Here we use a finite-element modeling approach to quantitatively understand possible mechanical interactions between a shallow pressure source beneath the summit caldera and the rift zones at Kīlauea Volcano (Hawai‘i). Past studies have demonstrated a strong connection between these structures, for example, with increases in seismic activity and extension across the rift, during phases of inflation of the summit. These observations suggest a coupling, which may modulate magma accumulation and transport processes along the rift.

How to cite: Pulvirenti, F., Aloisi, M., Carbone, D., Poland, M., and Vinciguerra, S.: Mechanical interactions between pressure sources and rift zones at Kilauea Volcano, Hawaii., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21540,, 2020

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Presentation version 1 – uploaded on 05 May 2020
  • CC1: Questions and answers from the live chat during EGU2020, Michael Heap, 11 May 2020

    Q: On what data did you basde your choice of Young's modulus?

    A: We started from the Lin tomography young modulus values. We start from Lin et al tomography data and we attempt to see how a reduction up to 50% of young's modulus fits the data at surface

    Q: What is causing the degradation of mechanical properties? Hydrothermal alteration?

    A: Then we consider percentages of degradation measured in the lab for basalts (heap et al., 2009)

    Q: In terms of number of sources used for the modelling, did you also incorporate the two reservoirs at the summit?

    A: We have one of the two sources inferred from geodetic, seimic and petrographic studies

    Q: What kind of source geometry do you invert with FEM?

    A: We do not inver for a source, we use a spherical source and we look for the parameters of pressure and position in a range of values

    Q: Inferred pressure values seem quite large. Can you comment on this?

    A: We are in the phase of assessing the overpressure versus lithostatic pressure, indeed a better pressure is obtained considering young's modukus reduction indeed

    Q: Nice work on the variations of mechanical properties! Would you be able to include anisotropic mechanical properties in your modeling?

    A: Absolutely, and also faults but that will be done after. We will also constraint better the model with insar data