Diffuse CO2 degassing and volcanic activity at Cape Verde islands, West Africa

Dionis, Samara; Pérez, Nemesio M.; Hernández, Pedro A.; Melián, Gladys V.; Rodríguez, Fátima; Padrón, Eleazar; Sumino, Hirochika; Barrrancos, Jose; Padilla, Germán D.; Fernandes, Paulo M.; Bandomo, Zuleyka; Silva, Sónia; Pereira, José Manuel; Semedo, Helio; Cabral, Jeremías

doi:10.1186/s40623-015-0219-x

Cited by 18 publications

(10 citation statements)

References 78 publications

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“…After that procedure, spatial distribution maps were constructed with sequential Gaussian simulation (sGs, Deutsch and Journel 1998;Cardellini et al 2003). This method was applied by interpolating over parts of the study area where the measurement sites were not set and to assess the uncertainty of total soil CO 2 emissions (Padrón et al 2008;Padrón et al 2015).…”

Section: Statistical Analysis and Constructing Spatial Distribution Mapsmentioning

confidence: 99%

Diffuse carbon dioxide emissions from hidden subsurface structures at Asama volcano, Japan

et al. 2016

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We measured diffuse carbon dioxide (CO 2 ) flux and soil temperature around the summit of Asama volcano, Japan to assess the diffuse degassing structure around the summit area. Soil CO 2 flux was measured using an accumulation chamber method, and the spatial distributions of CO 2 flux and soil temperature were derived from the mean of 100 sequential Gaussian simulations. Results show that soil CO 2 flux was high on the eastern flank of Kamayama cone and the eastern rim of Maekake crater, the outer cone. These areas mostly correspond to high-temperature anomalies. The average emission rate of diffuse CO 2 was calculated to be 12.6 t day −1 (12.2-14.6 t day −1 ). Such diffuse emissions account for 12 % of the total (diffuse and plume) CO 2 emissions from the summit area. The diffuse CO 2 anomalies probably reflect permeable zones controlled by local topography and hidden fractures bordering Maekake crater. The permeable zones are connected to the low-electrical-resistivity zone inferred to indicate both a hydrothermal fluid layer and an upper sealed layer made of clay minerals. Magmatic gas from the main conduit ascends to the volcano surface through this fluid layer and the permeable zones. These insights emphasize that the pathways and the connection between the pathways and the source of diffuse CO 2 combine to create the pattern of heterogeneous diffuse CO 2 emission seen at the surface. Only by using a combination of gas measurements and geophysical tools can we begin to understand the dynamics of this system as a whole.

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Section: Statistical Analysis and Constructing Spatial Distribution Mapsmentioning

confidence: 99%

Diffuse carbon dioxide emissions from hidden subsurface structures at Asama volcano, Japan

et al. 2016

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“…Fogo volcano is an island in the southwest end of the Cape Verde Archipelago, located at ~800 km west of the coast of Western Africa (Figure ). The Cape Verde Archipelago is entirely volcanic in origin [ Day et al ., ], and Fogo is one of the youngest and most active volcanic islands [ Courtney and White , ; Dionis et al ., ]. Fogo has an asymmetric conical shape, characterized by a 9 km wide collapse‐related depression on the east flank.…”

Section: Geological Setting and Eruptive History Of Fogomentioning

confidence: 99%

Lava flow hazard modeling during the 2014–2015 Fogo eruption, Cape Verde

et al. 2016

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Satellite remote sensing techniques and lava flow forecasting models have been combined to enable a rapid response during effusive crises at poorly monitored volcanoes. Here we used the HOTSAT satellite thermal monitoring system and the MAGFLOW lava flow emplacement model to forecast lava flow hazards during the 2014–2015 Fogo eruption. In many ways this was one of the major effusive eruption crises of recent years, since the lava flows actually invaded populated areas. Combining satellite data and modeling allowed mapping of the probable evolution of lava flow fields while the eruption was ongoing and rapidly gaining as much relevant information as possible. HOTSAT was used to promptly analyze MODIS and SEVIRI data to output hot spot location, lava thermal flux, and effusion rate estimation. This output was used to drive the MAGFLOW simulations of lava flow paths and to continuously update flow simulations. We also show how Landsat 8 OLI and EO‐1 ALI images complement the field observations for tracking the flow front position through time and adding considerable data on lava flow advancement to validate the results of numerical simulations. The integration of satellite data and modeling offers great promise in providing a unified and efficient system for global assessment and real‐time response to effusive eruptions, including (i) the current state of the effusive activity, (ii) the probable evolution of the lava flow field, and (iii) the potential impact of lava flows.

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“…Fogo volcano and the fumaroles located within the summit crater of Pico do Fogo (Figure 1c) [40][41][42]). The 2014-2015 eruption was jointly monitored by researchers from the University of Cape Verde (UNICV) and from INVOLCAN directly in field, and remotely by the Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Etneo (INGV-OE) of Italy through satellite images [30,43].…”

Section: Methodsmentioning

confidence: 99%

Satellite and Ground Remote Sensing Techniques to Trace the Hidden Growth of a Lava Flow Field: The 2014–2015 Effusive Eruption at Fogo Volcano (Cape Verde)

et al. 2018

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Fogo volcano erupted in 2014-2015 producing an extensive lava flow field in the summit caldera that destroyed two villages, Portela and Bangaeira. The eruption started with powerful explosive activity, lava fountains, and a substantial ash column accompanying the opening of an eruptive fissure. Lava flows spreading from the base of the eruptive fissure produced three arterial lava flows. By a week after the start of the eruption, a master lava tube had already developed within the eruptive fissure and along the arterial flow. In this paper, we analyze the emplacement processes based on observations carried out directly on the lava flow field, remote sensing measurements carried out with a thermal camera, SO 2 fluxes, and satellite images, to unravel the key factors leading to the development of lava tubes. These were responsible for the rapid expansion of lava for thẽ 7.9 km length of the flow field, as well as the destruction of the Portela and Bangaeira villages. The key factors leading to the development of tubes were the low topography and the steady magma supply rate along the arterial lava flow. Comparing time-averaged discharge rates (TADR) obtained from satellite and Supply Rate (SR) derived from SO 2 flux data, we estimate the amount and timing of the lava flow field endogenous growth, with the aim of developing a tool that could be used for hazard assessment and risk mitigation at this and other volcanoes.

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Diffuse CO2 degassing and volcanic activity at Cape Verde islands, West Africa

Cited by 18 publications

References 78 publications

Diffuse carbon dioxide emissions from hidden subsurface structures at Asama volcano, Japan

Diffuse carbon dioxide emissions from hidden subsurface structures at Asama volcano, Japan

Lava flow hazard modeling during the 2014–2015 Fogo eruption, Cape Verde

Satellite and Ground Remote Sensing Techniques to Trace the Hidden Growth of a Lava Flow Field: The 2014–2015 Effusive Eruption at Fogo Volcano (Cape Verde)

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