Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 16, 1925-1951, 2016
https://doi.org/10.5194/nhess-16-1925-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
17 Aug 2016
Lava flow hazard at Fogo Volcano, Cabo Verde, before and after the 2014–2015 eruption
Nicole Richter1, Massimiliano Favalli2, Elske de Zeeuw-van Dalfsen1, Alessandro Fornaciai2,3, Rui Manuel da Silva Fernandes4, Nemesio M. Pérez5,6, Judith Levy1, Sónia Silva Victória7, and Thomas R. Walter1 1German Research Centre for Geosciences (GFZ), Potsdam, 14473, Germany
2Istituto Nazionale di Geofisica e Vulcanologia (INGV), Pisa, 56126, Italy
3Dipartimento di Fisica e Astronomia (DIFA), Alma Mater Studiorum – Università di Bologna, Bologna, 40127, Italy
4Instituto D. Luiz, University of Beira Interior, Covilhã, 6201-001, Portugal
5Instituto Volcanológico de Canarias (INVOLCAN), 38400 Puerto de la Cruz, Tenerife, Spain
6Instituto Tecnológico y de Energías Renovables (ITER), 38611 Granadilla de Abona, Tenerife, Spain
7Universidade de Cabo Verde, Praia, Cabo Verde
Abstract. Lava flow simulations help to better understand volcanic hazards and may assist emergency preparedness at active volcanoes. We demonstrate that at Fogo Volcano, Cabo Verde, such simulations can explain the 2014–2015 lava flow crisis and therefore provide a valuable base to better prepare for the next inevitable eruption. We conducted topographic mapping in the field and a satellite-based remote sensing analysis. We produced the first topographic model of the 2014–2015 lava flow from combined terrestrial laser scanner (TLS) and photogrammetric data. This high-resolution topographic information facilitates lava flow volume estimates of 43.7 ± 5.2 × 106 m3 from the vertical difference between pre- and posteruptive topographies. Both the pre-eruptive and updated digital elevation models (DEMs) serve as the fundamental input data for lava flow simulations using the well-established DOWNFLOW algorithm. Based on thousands of simulations, we assess the lava flow hazard before and after the 2014–2015 eruption. We find that, although the lava flow hazard has changed significantly, it remains high at the locations of two villages that were destroyed during this eruption. This result is of particular importance as villagers have already started to rebuild the settlements. We also analysed satellite radar imagery acquired by the German TerraSAR-X (TSX) satellite to map lava flow emplacement over time. We obtain the lava flow boundaries every 6 to 11 days during the eruption, which assists the interpretation and evaluation of the lava flow model performance. Our results highlight the fact that lava flow hazards change as a result of modifications of the local topography due to lava flow emplacement. This implies the need for up-to-date topographic information in order to assess lava flow hazards. We also emphasize that areas that were once overrun by lava flows are not necessarily safer, even if local lava flow thicknesses exceed the average lava flow thickness. Our observations will be important for the next eruption of Fogo Volcano and have implications for future lava flow crises and disaster response efforts at basaltic volcanoes elsewhere in the world.

Citation: Richter, N., Favalli, M., de Zeeuw-van Dalfsen, E., Fornaciai, A., da Silva Fernandes, R. M., Pérez, N. M., Levy, J., Victória, S. S., and Walter, T. R.: Lava flow hazard at Fogo Volcano, Cabo Verde, before and after the 2014–2015 eruption, Nat. Hazards Earth Syst. Sci., 16, 1925-1951, https://doi.org/10.5194/nhess-16-1925-2016, 2016.
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Short summary
We provide a comprehensive lava flow hazard assessment for Fogo volcano, Cabo Verde before and after the 2014–2015 eruption based on probabilistic lava flow simulations. We find that the probability of lava flow invasion has not decreased at the location of two villages that were destroyed during this eruption, but have already started to be rebuilt. Our findings will be important for the next eruption of Fogo volcano and have implications for future lava flow crises elsewhere in the world.
We provide a comprehensive lava flow hazard assessment for Fogo volcano, Cabo Verde before and...
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