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East Anglia University, GB
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- PublicationRestrictedPre-eruptive vapour and its role in controlling eruption style and longevity at Soufrière Hills Volcano - Chapter 16(Geological Society, London, 2014)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ;; We use volatiles in melt inclusions and nominally anhydrous phenocrysts, with volcanic gas flux and composition, and textural analysis of mafic inclusions to estimate the mass of exsolved vapour prior to eruption at Soufrière Hills Volcano (SHV). Pre-eruptive andesite coexists with exsolved vapour comprising 1.6–2.4 wt% of the bulk magma. The water content of orthopyroxenes indicates a zone of magma storage at pressures of approximately 200–300 MPa, whereas melt inclusions have equilibrated at shallower pressures. Inclusions containing >3 wt% H2O are enriched in CO2, suggesting flushing with CO2-rich gases. Intruding mafic magma contains >8 wt% H2O at 200–300 MPa. Rapid quenching is accompanied by crystallization and vesiculation. Upon entrainment into the andesite, mafic inclusions may undergo disaggregation, where expansion of volatiles in the interior overcomes the strength of the crystal frameworks, thereby recharging the vapour content of the andesite. Exsolved vapour may amount to 4.3–8.2 vol% at 300 MPa, with implications for eruption longevity and volume; we estimate the magma reservoir volume to be 60–200 km3. Exsolved vapour may account for the small volume change at depth during eruptions from geodetic models, and has implications for magma flow: exsolution is likely to be in equilibrium during rapid magma ascent, with little nucleation of new bubbles.36 2 - PublicationOpen AccessRe-assessing volcanic hazard maps for improving volcanic risk communication: application to Stromboli Island, Italy.(2010-06-25)
; ; ; ; ;Nave, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Isaia, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Vilardo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Barclay, J.; University of East Anglia, UK.; ; ; Hazard and risk maps are tools for both mitigating against risk and informing and preparing the general public. Recent studies have highlighted that volcanic hazard and risk maps used during emergencies can be difficult to interpret. Our research focuses on evaluating and improving the efficacy of currently available maps of Stromboli volcano on Stromboli island (Italy) for the communication of volcanic hazard and risk information. Stromboli is an active volcano characterised by persistent explosive activity, sporadic lava effusions and landslides on the volcanos northwestern flank, which sometimes generates tsunamis, most recently in 2002. This study used semi-structured interviews conducted with local legislators, administrators and ‘enforcers’ to understand their perceptions of available risk information; to evaluate the respondents mental spatial maps; and to determine the most important components in encouraging risk-reducing behaviour in a hazardous situation. Respondents were asked to evaluate a contour map, an aerial photograph, a digital elevation model (DEM) and an innovative 3D tsunami risk map. These results enabled the development of different volcanic risk maps for use by ‘experts’ and ‘tourists’ using a contour map and a DEM (Scale 1:12.500). A 3D map focused on the tsunami risk (Scale 1:6.500) area was also produced.312 295 - PublicationOpen AccessRe-assessing Volcanic Hazard Maps for Improving Volcanic Risk Communication: Application to Stromboli Island, Italy(2010-05-31)
; ; ; ; ;Nave, Rosella; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Isaia, Roberto; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Vilardo, Giuseppe; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Barclay, Jenny; East Anglia University, GB; ; ; Hazard and risk maps are both sources of information about hazards and different risk levels, and tool for risk management and planning and in informing and preparing the general public. Recent studies have highlighted that volcanic hazard and risk maps, usually used during emergencies, are often difficult to be interpreted. Our research had the aim of assessing the efficacy of currently available hazard and risk maps through testing map understanding and comprehension, understanding and perception of the volcanic hazards and to elicit opinion about existing maps and the information that this group would like to see on map, in order to produce new, innovative and more suitable maps. The test area was Stromboli island, an active volcano characterised by a persistent low-to-moderate magnitude explosive activity, and by sporadic high magnitude explosive events and lava effusions. Landslides on the volcano North-Western flank have sometime generated tsunami. The study has been developed in different phases, using semi-structured interviews conducted with local legislators, administrators and ‘enforcers’, in order to highlight common misconceptions and perceptions, and to get information about respondents’ mental spatial maps. The maps to evaluate were respectively a contour, an aerial photo and a DEM maps, plus an innovative 3D tsunami risk map. On the basis of the obtained results two different volcanic hazard maps for both ‘expert’ and ‘tourist’ use, respectively using a contour map and a DEM and also a 3D map focused on the tsunami risk area have been produced.224 228