Eject! for Matlab

By Karen Strehlow1, Laura Sandri2, Jo Gottsmann3, Geoff Kilgour4, Alison Rust3, Roberto Tonini5

1. GEOMAR Helmholtz Centre for Ocean Research Kiel 2. Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Italy 3. University of Bristol 4. GNS Science 5. Istituto Nazionale di Geofisica e Vulcanologia, Italy

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The program "Eject!" calculates the trajectories of ballistic projectiles from volcanic eruptions (Mastin, 2001; 2011). The code was originally written in Visual Basic, which we have now translated into an editable Matlab procedure (Strehlow et al., 2017). Input parameters used here are exemplary for the case of Ruapehu volcano, but can be adapted to any specific case. Additionally, we have written a short script that compares the flight trajectory to the topography of the volcano to determine the flight distance.


We would like to acknowledge Larry Mastin for providing his original code for Eject! and his assistance with the translation into Matlab.



Mastin, LG (2001) A simple calculator of ballistic trajectories for blocks ejected during volcanic eruptions: U.S. Geological Survey Open-File Report 01-45, 16p; https://pubs.usgs.gov/of/2001/0045/.

Mastin, L (2011) eject model. https://vhub.org/resources/455.

Strehlow, K, Sandri, L, Gottsmann, JH, Kilgour, G, Rust, AC, Tonini, R (2017) Phreatic eruptions at crater lakes: occurrence statistics and probabilistic hazard forecast. Journal of Applied Volcanology, 6 (4), DOI 10.1186/s13617-016-0053-2.

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Researchers should cite this work as follows:

  • Karen Strehlow; Laura Sandri; Jo Gottsmann; Geoff Kilgour; Alison Rust; Roberto Tonini (2019), "Eject! for Matlab," https://vhub.org/resources/4543.

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