Ralf Gertisser | Keele University (original) (raw)
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Papers by Ralf Gertisser
Journal of Volcanology and Geothermal Research, Jun 1, 2012
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Basaltic volcanoes can remain active for tens to thousands of years with the continual presence o... more Basaltic volcanoes can remain active for tens to thousands of years with the continual presence of magma, requiring storage and transport conditions that can sustain persistently eruptible melt. Magma storage conditions beneath these volcanoes may significantly change with time, leading to sudden and dramatic changes in explosivity. Determining the rates and causes of these changes and how they modulate eruptive style over societally relevant timescales is of paramount importance for evaluating potential hazards. In June-August 2019, one major explosion and two paroxysms occurred at Stromboli volcano (Southern Italy) within only 64 days offering a unique opportunity to study the short-term variations in a basaltic plumbing system that can lead to paroxysmal events.Stromboli is an active open conduit basaltic volcano well-known for its persistent mild (normal) Strombolian activity occasionally interrupted by sudden, short-lived events ranging in size and intensity from major (violent Strombolian) to paroxysmal explosions. Strombolian activity, effusive eruptions and major explosions, all involve a degassed, highly porphyritic (hp) magma from a shallow reservoir. Deep-seated more mafic and, volatile-rich low-porphyritic (lp) magma is erupted, alongside hp-magma, during paroxysms, and in smaller quantities during some of the major explosions. Both lp- and hp-magmas were erupted during the 3 July and 28 August 2019 paroxysms, whereas only hp-magma was erupted during the major explosion on 25 June 2019.Via a multifaceted approach using clinopyroxene from the summer 2019 paroxysms, we reveal a key role for batches of volatile-rich lp-magma recharge arriving in the shallow reservoir up to a few days before these events. Our data indicate a rejuvenated Stromboli plumbing system where the extant crystal mush is efficiently permeated by recharge lp-magma with minimum remobilisation promoting a direct linkage between the deeper (lp) and shallow (hp) reservoirs. This sustains the current variability of eruptive styles with near immediate eruptive response to mafic magma recharge. The remarkable agreement between our calculated recharge timescales and the observed variation in time of various monitoring signals strongly supports such a model.Our approach provides vital insights into magma dynamics and their effects on monitoring signals demonstrating that detailed petrological studies integrated with volcano monitoring signals are fundamental for a fast response during a volcanic unrest phase or crisis.This work has been published in Nature Communication: Petrone, C.M., Mollo, S., Gertisser, R. et al. Magma recharge and mush rejuvenation drive paroxysmal activity at Stromboli volcano. Nat Commun 13, 7717 (2022). https://doi.org/10.1038/s41467-022-35405-z.
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AGUSM, May 1, 2009
The dynamics and depositional processes associated with block-and-ash flows (BAFs) are most commo... more The dynamics and depositional processes associated with block-and-ash flows (BAFs) are most commonly inferred to be a function of granular or inertial grain flow, similar to debris flows and cold rock avalanches. Existing geophysical mass flow models are either based on frictional (Mohr-Coulomb) behavior (the Titan2D model developed at the University of Buffalo, USA) or another rheological law (i.e., a
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Quaternary Science Reviews, Nov 1, 2018
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Journal of Volcanology and Geothermal Research, Nov 1, 2008
... 1 partly buried by overbank pyroclastic-flow deposits resulting from impact of the basal aval... more ... 1 partly buried by overbank pyroclastic-flow deposits resulting from impact of the basal avalanche; (g) pyroclastic surge deposits in the proximal part of Kali Gendol 1; (h) pyroclastic surge deposits decoupled from the basal avalanche below a 30-m-high cliff in Kali Gendol 1 ...
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Journal of Petrology, Mar 1, 2003
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Springer eBooks, 2022
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Springer eBooks, 2022
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Geology Today, Mar 1, 2017
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Applied Clay Science, Sep 1, 2018
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Journal of Quaternary Science, Aug 1, 2016
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Earth-Science Reviews, 2020
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Geology Today, May 1, 2010
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Geological Magazine, Nov 1, 2004
The Jurassic of Denmark and Greenland is rightly claimed by the publishers as a milestone publica... more The Jurassic of Denmark and Greenland is rightly claimed by the publishers as a milestone publication from GEUS, the now combined Geological Surveys of Denmark and Greenland. It represents the first issue of the new serial pub-lication, the Geological Survey of Denmark and ...
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Geological Magazine, Nov 1, 2006
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Bulletin of Volcanology, Mar 29, 2019
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Journal of Petrology, Oct 13, 2012
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Earth and Planetary Science Letters, Feb 1, 2005
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Geological Society, London, Memoirs, 2013
Stratigraphic, structural, volcanological and geochemical data allow a detailed reconstruction of... more Stratigraphic, structural, volcanological and geochemical data allow a detailed reconstruction of the geological history of the island of Salina (central Aeolian sector). Its subaerial volcanism (c. 244 ka to 15.6 ka) developed through six successive Eruptive Epochs interrupted by major quiescence periods, volcano-tectonic collapses and recurrent episodes of marine terrace formation during MIS 7 and MIS 5. Several stratovolcanoes were constructed by strombolian and effusive (Pizzo Capo, Monte Rivi, Monte Fossa delle Felci, Monte dei Porri) to hydromagmatic and subplinian (Monte dei Porri, Pollara) activity, with a general east–west shift of active vents, controlled primarily by the dominant NNW–SSE and minor NE–SW regional tectonic trends, and a progressive chemical differentiation of the erupted products from calc-alkaline basalts to rhyolites. The magma compositions and variations through time are the result of contamination of primary magmas derived from a subduction-modified mantle source with the Calabro–Peloritano lower crust and subsequent differentiation dominated by polybaric fractional crystallization. Magma mixing and mingling processes occurred during individual eruptions. The early basalts were fed from deep reservoirs located near the crust–mantle boundary, whereas the later andesitic to dacitic and, ultimately, rhyolitic magmas originated through combined assimilation and fractional crystallization processes in magma reservoirs at mid- to upper-crustal levels.DVD:The 10 000 scale geological map of Salina is included on the DVD in the printed book and can also be accessed online at http://www.geolsoc.org.uk/Memoir37-electronic. Also included is a full geochemical dataset for Salina.
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Journal of Volcanology and Geothermal Research, May 1, 2006
The eruptive history of Santorini was dominated by twelve major Plinian eruptions. Six of these (... more The eruptive history of Santorini was dominated by twelve major Plinian eruptions. Six of these (Middle Pumice, Vourvoulos, Upper Scoriae 1, Upper Scoriae 2, Cape Riva and Minoan) occurred during the past ∼150 ky. This study focuses on the stratigraphy and geochemistry of the interplinian pyroclastic deposits between 145 ka (Middle Pumice) and 3.6 ka (Minoan). Five interplinian eruptive intervals
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Journal of Volcanology and Geothermal Research, Jun 1, 2012
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Basaltic volcanoes can remain active for tens to thousands of years with the continual presence o... more Basaltic volcanoes can remain active for tens to thousands of years with the continual presence of magma, requiring storage and transport conditions that can sustain persistently eruptible melt. Magma storage conditions beneath these volcanoes may significantly change with time, leading to sudden and dramatic changes in explosivity. Determining the rates and causes of these changes and how they modulate eruptive style over societally relevant timescales is of paramount importance for evaluating potential hazards. In June-August 2019, one major explosion and two paroxysms occurred at Stromboli volcano (Southern Italy) within only 64 days offering a unique opportunity to study the short-term variations in a basaltic plumbing system that can lead to paroxysmal events.Stromboli is an active open conduit basaltic volcano well-known for its persistent mild (normal) Strombolian activity occasionally interrupted by sudden, short-lived events ranging in size and intensity from major (violent Strombolian) to paroxysmal explosions. Strombolian activity, effusive eruptions and major explosions, all involve a degassed, highly porphyritic (hp) magma from a shallow reservoir. Deep-seated more mafic and, volatile-rich low-porphyritic (lp) magma is erupted, alongside hp-magma, during paroxysms, and in smaller quantities during some of the major explosions. Both lp- and hp-magmas were erupted during the 3 July and 28 August 2019 paroxysms, whereas only hp-magma was erupted during the major explosion on 25 June 2019.Via a multifaceted approach using clinopyroxene from the summer 2019 paroxysms, we reveal a key role for batches of volatile-rich lp-magma recharge arriving in the shallow reservoir up to a few days before these events. Our data indicate a rejuvenated Stromboli plumbing system where the extant crystal mush is efficiently permeated by recharge lp-magma with minimum remobilisation promoting a direct linkage between the deeper (lp) and shallow (hp) reservoirs. This sustains the current variability of eruptive styles with near immediate eruptive response to mafic magma recharge. The remarkable agreement between our calculated recharge timescales and the observed variation in time of various monitoring signals strongly supports such a model.Our approach provides vital insights into magma dynamics and their effects on monitoring signals demonstrating that detailed petrological studies integrated with volcano monitoring signals are fundamental for a fast response during a volcanic unrest phase or crisis.This work has been published in Nature Communication: Petrone, C.M., Mollo, S., Gertisser, R. et al. Magma recharge and mush rejuvenation drive paroxysmal activity at Stromboli volcano. Nat Commun 13, 7717 (2022). https://doi.org/10.1038/s41467-022-35405-z.
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AGUSM, May 1, 2009
The dynamics and depositional processes associated with block-and-ash flows (BAFs) are most commo... more The dynamics and depositional processes associated with block-and-ash flows (BAFs) are most commonly inferred to be a function of granular or inertial grain flow, similar to debris flows and cold rock avalanches. Existing geophysical mass flow models are either based on frictional (Mohr-Coulomb) behavior (the Titan2D model developed at the University of Buffalo, USA) or another rheological law (i.e., a
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Quaternary Science Reviews, Nov 1, 2018
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Journal of Volcanology and Geothermal Research, Nov 1, 2008
... 1 partly buried by overbank pyroclastic-flow deposits resulting from impact of the basal aval... more ... 1 partly buried by overbank pyroclastic-flow deposits resulting from impact of the basal avalanche; (g) pyroclastic surge deposits in the proximal part of Kali Gendol 1; (h) pyroclastic surge deposits decoupled from the basal avalanche below a 30-m-high cliff in Kali Gendol 1 ...
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Journal of Petrology, Mar 1, 2003
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Springer eBooks, 2022
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Springer eBooks, 2022
Bookmarks Related papers MentionsView impact
Geology Today, Mar 1, 2017
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Applied Clay Science, Sep 1, 2018
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Journal of Quaternary Science, Aug 1, 2016
Bookmarks Related papers MentionsView impact
Earth-Science Reviews, 2020
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Geology Today, May 1, 2010
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Geological Magazine, Nov 1, 2004
The Jurassic of Denmark and Greenland is rightly claimed by the publishers as a milestone publica... more The Jurassic of Denmark and Greenland is rightly claimed by the publishers as a milestone publication from GEUS, the now combined Geological Surveys of Denmark and Greenland. It represents the first issue of the new serial pub-lication, the Geological Survey of Denmark and ...
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Geological Magazine, Nov 1, 2006
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Bulletin of Volcanology, Mar 29, 2019
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Journal of Petrology, Oct 13, 2012
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Earth and Planetary Science Letters, Feb 1, 2005
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Geological Society, London, Memoirs, 2013
Stratigraphic, structural, volcanological and geochemical data allow a detailed reconstruction of... more Stratigraphic, structural, volcanological and geochemical data allow a detailed reconstruction of the geological history of the island of Salina (central Aeolian sector). Its subaerial volcanism (c. 244 ka to 15.6 ka) developed through six successive Eruptive Epochs interrupted by major quiescence periods, volcano-tectonic collapses and recurrent episodes of marine terrace formation during MIS 7 and MIS 5. Several stratovolcanoes were constructed by strombolian and effusive (Pizzo Capo, Monte Rivi, Monte Fossa delle Felci, Monte dei Porri) to hydromagmatic and subplinian (Monte dei Porri, Pollara) activity, with a general east–west shift of active vents, controlled primarily by the dominant NNW–SSE and minor NE–SW regional tectonic trends, and a progressive chemical differentiation of the erupted products from calc-alkaline basalts to rhyolites. The magma compositions and variations through time are the result of contamination of primary magmas derived from a subduction-modified mantle source with the Calabro–Peloritano lower crust and subsequent differentiation dominated by polybaric fractional crystallization. Magma mixing and mingling processes occurred during individual eruptions. The early basalts were fed from deep reservoirs located near the crust–mantle boundary, whereas the later andesitic to dacitic and, ultimately, rhyolitic magmas originated through combined assimilation and fractional crystallization processes in magma reservoirs at mid- to upper-crustal levels.DVD:The 10 000 scale geological map of Salina is included on the DVD in the printed book and can also be accessed online at http://www.geolsoc.org.uk/Memoir37-electronic. Also included is a full geochemical dataset for Salina.
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Journal of Volcanology and Geothermal Research, May 1, 2006
The eruptive history of Santorini was dominated by twelve major Plinian eruptions. Six of these (... more The eruptive history of Santorini was dominated by twelve major Plinian eruptions. Six of these (Middle Pumice, Vourvoulos, Upper Scoriae 1, Upper Scoriae 2, Cape Riva and Minoan) occurred during the past ∼150 ky. This study focuses on the stratigraphy and geochemistry of the interplinian pyroclastic deposits between 145 ka (Middle Pumice) and 3.6 ka (Minoan). Five interplinian eruptive intervals
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The Middle Pumice A eruption of Santorini, Greece (144.6 ka) is a fine example of a welded Plinia... more The Middle Pumice A eruption of Santorini, Greece (144.6 ka) is a fine example of a welded Plinian air-fall deposit. Welding characteristics and factors controlling welding were determined through field observations and laboratory analysis such as pumice clast characterisation, Rf/phi strain analysis and physical eruption parameter calculations. Welding intensity varies vertically and laterally, with welding decreasing away from source, and increasing centrally. Lateral welding zones are defined by the highest observed welding grade: A = densely-welded (< 0.25 km from source); B = slightly- welded (0.25-2.38 km); C = tack-welded (2.38-3.71 km), and D = non-welded (> 3.71 km). With welding, there is increased density and decreased porosity. A density of 2.36 gcm-3 and porosity of 4.9% is found in the most densely-welded section. Distal, non-welded pumices have densities of 0.37 gcm-3 and porosities of > 75%. Strain calculations show the deposit is moderately flattened but relatively undeformed. Accumulation rates and deposit thicknesses decrease away from source, with ~10.5 mh-1 and 25.8 m in proximal areas, and 0.77-1.26 mh-1 and ~3 m at distal locations. Threshold values of accumulation rate are > 7.5 mh-1 for dense welding, 3.0-7.5 mh-1 for slight welding and < 3 mh-1 for tack- to non-welding. An eruption column height of 23 km and mass discharge rate of 3.0 x 107 kg s-1 were calculated. The deposit is dacitic to andesitic, becoming increasingly mafic with stratigraphic height. First order factors controlling welding are deposit thickness and accumulation rate. High emplacement temperatures and magmatic temperatures are secondary factors.
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Nature GeoScience, 2021
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Nature Geoscience, 2021
Sea-level change is thought to influence the frequencies of volcanic eruptions on glacial to inte... more Sea-level change is thought to influence the frequencies of volcanic eruptions on glacial to interglacial timescales. However, the underlying physical processes and their importance relative to other influences (for example, magma recharge rates) remain poorly understood. Here we compare an approximately 360-kyr-long record of effusive and explosive eruptions from the flooded caldera volcano at Santorini (Greece) with a high-resolution sea-level record spanning the last four glacial-interglacial cycles. Numerical modelling shows that when the sea level falls by 40 m below the present-day level, the induced tensile stresses in the roof of the magma chamber of Santorini trigger dyke injections. As the sea level continues to fall to −70 or −80 m, the induced tensile stress spreads throughout the roof so that some dykes reach the surface to feed eruptions. Similarly, the volcanic activity gradually disappears after the sea level rises above −40 m. Synchronizing Santorini’s stratigraphy with the sea-level record using tephra layers in marine sediment cores shows that 208 out of 211 eruptions (both effusive and explosive) occurred during periods constrained by sea-level falls (below −40 m) and subsequent rises, suggesting a strong absolute sea-level control on the timing of eruptions on Santorini—a result that probably applies to many other volcanic islands around the world.
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