Electronic Supplementary Material: "Event trees and epistemic uncertainty in long-term volcanic hazard assessment of rift volcanoes: the example of Aluto (Central Ethiopia)", by Tierz, P., Clarke, B., Calder, E. S., Dessalegn, F., Lewi, E., Yirgu, G., Fontijn, K., Crummy, J. M., and Loughlin, S. C., submitted to Geochemistry, Geophysics, Geosystems. The datasets contain volcanological data on analogue (i.e. similar) volcanoes of Aluto volcano (Ethiopia), including conditional probabilities of eruption size, number of eruptions with specific volcanic phenomena reported and values of volcano analogy calculated using the VOLCano ANalogues Search tool (VOLCANS, Tierz et al., 2019, https://doi.org/10.1007/s00445-019-1336-3). These type of data can be used to parameterise event tree models (e.g. Newhall and Hoblitt, 2002, https://doi.org/10.1007/s004450100173; Marzocchi et al., 2010, https://doi.org/10.1007/s00445-010-0357-8) and, thus, quantify volcanic hazard at a particular volcano of interest, including the relevant sources of uncertainty. The production of the datasets was supported by the UK Natural Environment Research Council project: Rift Volcanism: Past, Present and Future (RiftVolc). Grant NE/L013460/1.

Diffuse CO2 degassing data from three campaigns across the Main Ethiopian Rift. Data are referenced in Hunt et al., 2017: Spatially variable CO2 degassing in the Main Ethiopian Rift: Implications for magma storage, volatile transport and rift-related emissions; https://doi.org/10.1002/2017GC006975.

Ar/Ar dating of samples from Aluto and Corbetti volcanoes, Ethiopia. Data are referenced in Hutchison et al., 2016b: A pulse of mid-Pleistocene rift volcanism in Ethiopia at the dawn of modern humans; https://doi.org/10.1038/ncomms13192

This dataset contains 204 ascending and 300 descending Sentinel-1 geocoded unwrapped interferograms and coherence, and 70 ascending and 102 descending Re-sampled Single Look Complex (RSLC) images for each acquisition date. This data set also includes the original size Digital Elevation Model (DEM) used during InSAR processing. Data used by: Moore et al, 2019, “The 2017 Eruption of Erta 'Ale Volcano, Ethiopia: Insights into the Shallow Axial Plumbing System of an Incipient Mid-Ocean Ridge”.

Isotopic geochemical analysis of volcanic samples from across Ethiopia. Data are referenced in Hutchison et al., 2018: The evolution of magma during continental rifting: New constraints from the isotopic and trace element signatures of silicic magmas from Ethiopian volcanoes; https://doi.org/10.1016/j.epsl.2018.02.027

Geochemical analysis of volcanic samples from Aluto, Fentale, and Kone volcanoes, Ethiopia. Data are referenced in Iddon et al., 2018: Mixing and Crystal Scavenging in the Main Ethiopian Rift Revealed by Trace Element Systematics in Feldspars and Glasses; https://doi.org/10.1029/2018GC007836.

This data set contains 119 unwrapped and geocoded inteferograms derived from Cosmo-SkyMed (CSK) SAR scenes aquired over the Northen Main Ethiopian Rift between June 2014 and December 2015. This data set also contains displacement time series derived from processed CSK and Sentinel-1 inteferograms at the locations specified in the accompanying README files

Geochemical analysis of and Ar/Ar dating for volcanic samples from Aluto volcano, Ethiopia. Data are referenced in Hutchison et al., 2016c: The eruptive history and magmatic evolution of Aluto volcano: new insights into silicic peralkaline volcanism in the Ethiopian rift; https://doi.org/10.1016/j.jvolgeores.2016.09.010

Petrological and geochemical analysis of tephra samples from Aluto volcano, Ethiopia. Data are referenced in McNamara et al., 2018: Using Lake Sediment Cores to Improve Records of Volcanism at Aluto Volcano in the Main Ethiopian Rift; https://doi.org/10.1029/2018GC007686.

Geochemical data has been collected on samples from new exposures of the 1883 deposits, revealed by the 2018 tsunamigenic flank collapse of Anak Krakatau, which provides improved stratigraphic context. Whole-rock data taken by X-ray Florescence shows no systematic stratigraphic correlation. Chemical data for transects across, and spot points on, plagioclase phenocrysts, including some trace element data, all obtained using Electron Probe Microanalysis (EPMA), with Backscatter electron (BSE) images of crystals, obtained using Scanning Electron Microscope, reveal complex zoning profiles. However, chemical data for transects across pyroxene phenocrysts, obtained using EPMA, show this phenocryst phase is largely unzoned. The dataset also includes chemical data for spots on Fe/Ti oxides, included on the rims of pyroxene, and obtained using EPMA. Matrix glass chemistry, obtained via EPMA, shows that the early eruptive ash is more evolved than the pyroclastic material that follows, and that there is a slight overall trend to a more homogenous, less evolved melt composition. The 1883 eruption of Krakatau was a large, cardera-forming eruption that caused approximately 36,000 fatalities. It is also the only eruption of its size to have accompanying written accounts.