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Sumarti, S.
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- PublicationRestrictedThe 2010 explosive eruption of Java's Merapi volcano—A ‘100-year’ event(2012)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Surono, N.; CVGHM ;Jousset, P.; BRGM ;Pallister, J.; USGS ;Boichu, M.; University of Cambridge ;Buongiorno, M. F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Budisantoso, A.; BPPTK ;Costa, F.; Earth Observatory of Singapore ;Andreastuti, S.; CVGHM ;Prata, F.; Norwegian Institute for Air Research ;Schneider, D.; USGS ;Clarisse, L.; Université Libre de Bruxelle ;Humaida, H.; BPPTK ;Sumarti, S.; CVGHM ;Bignami, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Griswold, J.; USGS ;Carn, S.; Norwegian Institute for Air Research ;Oppenheimer, C.; University of Cambridge ;Lavigne, F.; Laboratoire de Géographie Physique; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Merapi volcano (Indonesia) is one of the most active and hazardous volcanoes in the world. It is known for frequent small to moderate eruptions, pyroclastic flows produced by lava dome collapse, and the large population settled on and around the flanks of the volcano that is at risk. Its usual behavior for the last decades abruptly changed in late October and early November 2010, when the volcano produced its largest and most explosive eruptions in more than a century, displacing at least a third of a million people, and claiming nearly 400 lives. Despite the challenges involved in forecasting this ‘hundred year eruption’, we show that the magnitude of precursory signals (seismicity, ground deformation, gas emissions) was proportional to the large size and intensity of the eruption. In addition and for the first time, near-real-time satellite radar imagery played an equal role with seismic, geodetic, and gas observations in monitoring eruptive activity during a major volcanic crisis. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) issued timely forecasts of the magnitude of the eruption phases, saving 10,000–20,000 lives. In addition to reporting on aspects of the crisis management, we report the first synthesis of scientific observations of the eruption. Our monitoring and petrologic data show that the 2010 eruption was fed by rapid ascent of magma from depths ranging from 5 to 30km. Magma reached the surface with variable gas content resulting in alternating explosive and rapid effusive eruptions, and released a total of ~0.44Tg of SO2. The eruptive behavior seems also related to the seismicity along a tectonic fault more than 40km from the volcano, highlighting both the complex stress pattern of the Merapi region of Java and the role of magmatic pressurization in activating regional faults. We suggest a dynamic triggering of the main explosions on 3 and 4 November by the passing seismic waves generated by regional earthquakes on these days.359 71 - PublicationRestrictedStructure and CO2 budget of Merapi volcano during inter-eruptive periods(2009-02-19)
; ; ; ; ; ; ;Toutain, J. P.; Université de Toulouse; UPS (OMP); LMTG, ;Sortino, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Baubron, J. C.; JcbConsulting ;Richon, P.; CEA, DIF, Service Radiochimie Chimie Environnemen ;Surono; DVGHM ;Sumarti, S.; MVO – Merapi Volcanological Observatory; ; ;; ; Abstract Soil temperature and gas (CO2 concentration and flux) have been investigated at Merapi volcano (Indonesia) during two inter-eruptive periods (2002 and 2007). Precise imaging of the summit crater and the spatial pattern of diffuse degassing along a gas traverse on the southern slope are interpreted in terms of summit structure and major caldera organization. The summit area is characterized by decreasing CO2 concentrations with distance from the 1932 crater rim, down to atmospheric levels at the base of the terminal cone. Similar patterns are measured on any transect down the slopes of the cone. The spatial distribution of soil gas anomalies suggests that soil degassing is controlled by structures identified as concentric historical caldera rims (1932, 1872, and 1768), which have undergone severe hydrothermal self-sealing processes that dramatically lower the permeability and porosity of soils. Temperature and CO2 flux measurements in soils near the dome display heterogeneous distributions which are consistent with a fracture network identified by previous geophysical studies. These data support the idea that the summit is made of isolated and mobile blocks, whose boundaries are either sealed by depositional processes or282 34