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Amelung, F.
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Amelung, F.
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- PublicationRestrictedFeedback processes between magmatic events and flank movement at Mount Etna (Italy) during the 2002-2003 eruption(2005-10-27)
; ; ; ; ;Walter, T. R.; GeoForschungsZentrum Potsdam, Potsdam, Germany ;Acocella, V.; Dipartimento di Scienze Geologiche, Università di Roma TRE, Rome, Italy ;Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Amelung, F.; Marine Geology and Geophysics Division, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA; ; ; The 2002–2003 Mount Etna eruption and the associated deformation provide a unique possibility to study the relationships between volcanism and volcano instability. The sequence started with movement of the eastern volcano flank and was associated with earthquakes and the formation of surface ruptures. Then the eruption occurred from fissures at the north and south rift zones and was followed by additional flank movement, seismic swarms, and surface ruptures. The overall area of flank movement implicated more than 700 km2. In this paper we investigate how episodes of magmatic events (eruptions and intrusions) and flank movement interact. In three-dimensional numerical models we simulate the volcano-tectonic events and calculate changes in the static stress field. The models suggest that the 2002–2003 events are the result of interrelated processes consisting of (1) the preeruptive intrusion of magma and inflation of the volcano, which induced (2) the movement of the volcano east flank, (3) facilitated the eruption, and (4) led to the slip of a much larger part of the eastern and southeastern flanks. Understanding the precise interconnectivity of these processes may help to forecast the behavior during future volcanic crisis at Mount Etna, which is crucial in minimizing volcanic and seismic hazards on the highly populated eastern sector of the volcano.173 73 - PublicationRestrictedGravity changes and deformation at Kīlauea Volcano, Hawaii, associated with summit eruptive activity, 2009–2012(2014)
; ; ; ; ; ; ;Bagnardi, M.; School of Earth and Environment, University of Leeds, Leeds, UK ;Poland, M. P.; Hawaiian Volcano Observatory, U.S. Geological Survey, Hawaii, USA ;Carbone, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Baker, S.; UNAVCO, Boulder, Colorado, USA ;Battaglia, M.; Department of Earth Sciences, Sapienza, University of Rome, Rome, Italy ;Amelung, F.; Division of Marine Geology and Geophysics, RSMAS, University of Miami, Coral Gables, Florida, USA; ; ; ; ; Analysis of microgravity and surface displacement data collected at the summit of Kīlauea Volcano, Hawaii (USA), between December 2009 and November 2012 suggests a net mass accumulation at ~1.5 km depth beneath the northeast margin of Halema‘uma‘u Crater, within Kīlauea Caldera. Although residual gravity increases and decreases are accompanied by periods of uplift and subsidence of the surface, respectively, the volume change inferred from the modeling of interferometric synthetic aperture radar deformation data can account for only a small portion (as low as 8%) of the mass addition responsible for the gravity increase. We propose that since the opening of a new eruptive vent at the summit of Kīlauea in 2008, magma rising to the surface of the lava lake outgasses, becomes denser, and sinks to deeper levels, replacing less dense gas-rich magma stored in the Halema‘uma‘u magma reservoir. In fact, a relatively small density increase (<200 kgm_3) of a portion of the reservoir can produce the positive residual gravity change measured during the period with the largest mass increase, between March 2011 and November 2012. Other mechanisms may also play a role in the gravity increase without producing significant uplift of the surface, including compressibility of magma, formation of olivine cumulates, and filling of void space by magma. The rate of gravity increase, higher than during previous decades, varies through time and seems to be directly correlated with the volcanic activity occurring at both the summit and the east rift zone of the volcano.334 49