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Gunawan, Hendra
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Gunawan, Hendra
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- PublicationOpen AccessCooperazione Italia-Indonesia:un sistema per il monitoraggio sismologico del vulcano Marapi (Sumatra)(2009)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Orazi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Peluso, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;D'Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Caputo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Demartin, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Franceschi, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Delladio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Budianto, A.; CVGHM (Directorate of Volcanology and Geological Hazard Mitigation) ;Gunawan, H.; CVGHM (Directorate of Volcanology and Geological Hazard Mitigation) ;Selva, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Garcia, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Giudicepietro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Marzocchi, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Surono; CVGHM (Directorate of Volcanology and Geological Hazard Mitigation) ;Boschi, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia; ; ; ; ; ; ; ; ; ; ; ; ; ; ; L’Italia e l’Indonesia hanno avviato nel 2005-2006 un progetto di cooperazione sulle tematiche della mitigazione del rischio vulcanico. Nell’ambito di questo progetto è stata individuata la zona ovest di Sumatra come area di intervento. In particolare è stato preso in considerazione il vulcanoMarapi. Questo vulcano ha avuto frequente attività eruttiva nelle ultime decine di anni. L’ultima eruzione si è verificata nel 2004. La sua attività, sebbene di moderata intensità, pone un problema di protezione civile, poiché dal 1980 ad oggi ha causato diversi feriti e alcune vittime tra i turisti che hanno visitato l’area craterica sommitale. Allo scopo di monitorare lo stato di attività del Marapi, nell’ambito del citato progetto è stata realizzata una rete sismica a larga banda composta da 4 stazioni e basata su sensori Guralp GMG-40T da 60s di periodo e su acquisitori di tipo GAIA2, prodotti presso l’Istituto Nazionale di Geofisica e Vulcanologia. La strumentazione è stata portata dall’Italia ed è stata installata da un gruppo di lavoro formato da italiani ed indonesiani. Oltre all’installazione della strumentazione in campagna è stato necessario allestire un vero e proprio Centro di Monitoraggio presso l’Osservatorio di Bukittinggi, in prossimità delle pendici nordoccidentali del vulcano, dotato di calcolatori per l’acquisizione, l’analisi dei dati e la loro archiviazione. Il sistema per ilmonitoraggio sismologico realizzato alMarapi costituisce un importante strumento di prevenzione del rischio associato all’attività di questo vulcano e sta permettendo di creare un ricco data set utile a caratterizzare la sismicità della struttura vulcanica e dell’area circostante. Da un’analisi preliminare dei dati registrati nel periodo 19/10/2006 - 24/11/2008 si evidenzia che il vulcanomanifesta una sismicità di tipo VT ed LP. Nell’ agosto 2007 sono stati inoltre registrati segnali probabilmente attribuibili a modesta attività esplosiva nell’area sommitale. Italy and Indonesia started a cooperation project in 2005-2006 to cover issues for the mitigation of volcanic risk. In this project, the west area of Sumatra was identified as the area for intervention. In particular, the Marapi volcano was considered. This volcano has shown frequent eruptive activity over recent decades, with the last eruption occurring in 2004. Although its activity is of moderate intensity, it creates a civil protection problem, because since 1980 it has resulted in several injuries and a number of deaths among the tourists who visit the summit crater area. To monitor the activity of Marapi volcano as part of this project, a broadband seismic network has been implemented that consists of four stations based on Guralp GMG 40T sensors with period of 60 s and on GAIA2 data-loggers, which are produced at the INGV. The instrumentation was brought from Italy and was installed by a working group comprising Italians and Indonesians. In addition to the instrumentation in the field, it was necessary to set up a monitoring centre in the Bukittinggi Observatory, which is near the north-western slopes of the Marapi volcano. This is equipped with computers for data acquisition, analysis and archiving. The system for seismological monitoring that has been realized atMarapi volcano is an important tool in the prevention of the risk associated with this volcano, and it is providing a rich dataset that will be of great use for the characterization of the seismicity of the Marapi volcanic structure and the surrounding area. A preliminary analysis of the data recorded during the period 19/10/2006 - 24/11/2008 evidences that the volcano shows VT and LP seismicity. In August 2007 were also recorded signals probably attributable to small explosive activity in the summit area.759 169 - PublicationRestrictedFirst determination of magma-derived gas emissions from Bromo volcano, eastern Java (Indonesia)(2015-09-10)
; ; ; ; ; ; ; ; ;Aiuppa, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Bani, P.; Center for Volcanology and Geological Hazard Mitigation, Jl. Diponegoro No 57, Bandung, Indonesia ;Moussallam, Y.; Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK ;Di Napoli, R.; DiSTeM, Università di Palermo, Italy ;Allard, P.; Institut de Physique du Globe de Paris, UMR7154 CNRS, 75005 Paris, France ;Gunawan, H.; Center for Volcanology and Geological Hazard Mitigation, Jl. Diponegoro No 57, Bandung, Indonesia ;Hendrasto, M.; Center for Volcanology and Geological Hazard Mitigation, Jl. Diponegoro No 57, Bandung, Indonesia ;Tamburello, G.; DiSTeM, Università di Palermo, Italy; ; ; ; ; ; ; The composition and fluxes of volcanic gases released by persistent open-vent degassing at Bromo Volcano, east Java (Indonesia), were characterised in September 2014 from both in-situ Multi-GAS analysis and remote spectroscopic (dual UVcamera)measurements of volcanic plumeemissions. Our results demonstrate that Bromo volcanic gas is water-rich (H2O/SO2 ratios of 56–160) and has CO2/SO2 (4.1 ± 0.7) and CO2/Stot (3.2 ± 0.7) ratios within the compositional range of other high-temperature magma-derived gases in Indonesia. H2/H2O and H2S/SO2 ratios constrain a magmatic gas source with minimal temperature of ~700 °C and oxygen fugacity of 10-17–10-18 bars. UV camera sensing on September 20 and 21, 2014 indicates a steady daily mean SO2 output of 166 ± 38 t d−1, which is ten times higher than reported from few previous studies. Our results indicate that Bromo ranks amongst the strongest sources of quiescent volcanic SO2 emission measured to date in Indonesia, being comparable to Merapi volcano in central Java. By combining our results for the gas composition with the SO2 plume flux, we assess for the first time the fluxes of H2O (4725 ± 2292 t d−1), CO2 (466 ± 83 t d−1), H2S (25 ± 12 t d−1) and H2 (1.1 ± 0.8) from Bromo. Our study thus contributes a new piece of information to the still limited data base for volcanic gas emissions in Indonesia, and confirms that much remain to be done to fully assess the contribution of this very active arc region to global volcanic gas fluxes.427 23 - PublicationRestrictedVolcano-hydrothermal system and activity of Sirung volcano (Pantar Island, Indonesia)Sirung is a frequently active volcano located in the remote parts of Western Timor (Indonesia). Sirung has a crater with several hydrothermal features including a crater lake. We present a timeseries of satellite images of the lake and chemical and isotope data from the hyperacid hydrothermal system. The fluids sampled in the crater present the typical features of hyperacidic systems with high TDS, low pH and d34SHSO4 –d34SS0 among the highest for such lakes. The cations concentrations are predominantly controlled by the precipitation of alunite, jarosite, silica phases, native sulfur and pyrite which dominate the shallow portions of the hydrothermal system. These minerals may control shallow sealing processes thought to trigger phreatic eruptions elsewhere. Sparse Mg/Cl and SO4/Cl ratios and lake parameters derived from satellite images suggest gradual increase in heat and gas flux, most likely SO2-rich, prior to the 2012 phreatic eruption. An acidic river was sampled 8 km far from the crater and is genetically linked with the fluids rising toward the active crater. This river would therefore be a relevant target for future remote monitoring purposes. Finally, several wells and springs largely exceeded the World Health Organization toxicity limits in total arsenic and fluoride.
161 4 - PublicationRestrictedDukono, the predominant source of volcanic degassing in Indonesia, sustained by a depleted Indian-MORB(2018)
; ; ; ; ; ; ; ; ; ; ;; ;; ; ; ; ; ;Located on Halmahera island, Dukono is among the least known volcanoes in Indonesia. A compilation of the rare available reports indicates that this remote and hardly accessible volcano has been regularly in eruption since 1933, and has undergone nearly continuous eruptive manifestation over the last decade. The first study of its gas emissions, presented in this work, highlights a huge magmatic volatile contribution into the atmosphere, with an estimated annual output of about 290 kt of SO2, 5000 kt of H2O, 88 kt of CO2, 5 kt of H2S and 7 kt of H2. Assuming these figures are representative of the long-term continuous eruptive activity, then Dukono is the current most prominent volcanic gas discharge point in Indonesia and ranks among the top-ten volcanic SO2 sources on earth. Combining our findings with other recent volcanic SO2 flux results, obtained during periodic campaigns at a number of volcanoes with DOAS and UV-Cameras, the SO2 emission budget for Indonesia is estimated at 540 kt year−1, representing 2–3% of the global volcanic SO2 contribution into the atmosphere. This figure should be considered as minimum as gas emissions from numerous other active volcanoes in Indonesia are yet to be evaluated. This voluminous degassing output from Dukono is sustained by a depleted Indian-MORB (I-MORB) mantle source. This latter is currently undergoing lateral pressure from the steepening of the subducted slab, the downward force from the Philippine Sea plate and the westward motion of a continental fragments along the Sorong fault, leading to high fluid fluxes to the surface. Over the course of Dukono eruptive activity, the magma reservoir has changed from a less differentiated source that fed the past voluminous lava flows to a more evolved melt that sustained the current ongoing explosive activity.318 7 - PublicationOpen AccessSynoptic analysis of a decade of daily measurements of SO2 emission in the troposphere from volcanoes of the global ground-based Network for Observation of Volcanic and Atmospheric Change(2021)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ;; ; ; ;; Volcanic plumes are common and far-reaching manifestations of volcanic activity during and be-tween eruptions. Observations of the rate of emission and composition of volcanic plumes are essential to rec-ognize and, in some cases, predict the state of volcanic activity. Measurements of the size and location of theplumes are important to assess the impact of the emission from sporadic or localized events to persistent orwidespread processes of climatic and environmental importance. These observations provide information onvolatile budgets on Earth, chemical evolution of magmas, and atmospheric circulation and dynamics. Space-based observations during the last decades have given us a global view of Earth’s volcanic emission, particularlyof sulfur dioxide (SO2). Although none of the satellite missions were intended to be used for measurementof volcanic gas emission, specially adapted algorithms have produced time-averaged global emission budgets.These have confirmed that tropospheric plumes, produced from persistent degassing of weak sources, dominatethe total emission of volcanic SO2. Although space-based observations have provided this global insight intosome aspects of Earth’s volcanism, it still has important limitations. The magnitude and short-term variabilityof lower-atmosphere emissions, historically less accessible from space, remain largely uncertain. Operationalmonitoring of volcanic plumes, at scales relevant for adequate surveillance, has been facilitated through the useof ground-based scanning differential optical absorption spectrometer (ScanDOAS) instruments since the be-ginning of this century, largely due to the coordinated effort of the Network for Observation of Volcanic andAtmospheric Change (NOVAC). In this study, we present a compilation of results of homogenized post-analysisof measurements of SO2flux and plume parameters obtained during the period March 2005 to January 2017of 32 volcanoes in NOVAC. This inventory opens a window into the short-term emission patterns of a diverseset of volcanoes in terms of magma composition, geographical location, magnitude of emission, and style oferuptive activity. We find that passive volcanic degassing is by no means a stationary process in time and thatlarge sub-daily variability is observed in the flux of volcanic gases, which has implications for emission budgetsproduced using short-term, sporadic observations. The use of a standard evaluation method allows for intercom-parison between different volcanoes and between ground- and space-based measurements of the same volcanoes.The emission of several weakly degassing volcanoes, undetected by satellites, is presented for the first time. Wealso compare our results with those reported in the literature, providing ranges of variability in emission notaccessible in the past. The open-access data repository introduced in this article will enable further exploitationof this unique dataset, with a focus on volcanological research, risk assessment, satellite-sensor validation, andimproved quantification of the prevalent tropospheric component of global volcanic emission.405 49