Volcanic eruptions differ enormously in their size and impacts, ranging from quiet lava flow effusions along the volcano flanks to colossal events with the potential to affect our entire ...civilization. Knowledge of the time and size distribution of volcanic eruptions is of obvious relevance for understanding the dynamics and behavior of the Earth system, as well as for defining global volcanic risk. From the analysis of recent global databases of volcanic eruptions extending back to more than 2 million years, I show here that the return times of eruptions with similar magnitude follow an exponential distribution. The associated relative frequency of eruptions with different magnitude displays a power law, scale-invariant distribution over at least six orders of magnitude. These results suggest that similar mechanisms subtend to explosive eruptions from small to colossal, raising concerns on the theoretical possibility to predict the magnitude and impact of impending volcanic eruptions.
The May 2018 rift intrusion and eruption of Kīlauea Volcano, Hawai'i, represented one of its most extraordinary eruptive sequences in at least 200 years, yet the trigger mechanism remains elusive
. ...The event was preceded by several months of anomalously high precipitation. It has been proposed that rainfall can modulate shallow volcanic activity
, but it remains unknown whether it can have impacts at the greater depths associated with magma transport. Here we show that immediately before and during the eruption, infiltration of rainfall into Kīlauea Volcano's subsurface increased pore pressure at depths of 1 to 3 kilometres by 0.1 to 1 kilopascals, to its highest pressure in almost 50 years. We propose that weakening and mechanical failure of the edifice was driven by changes in pore pressure within the rift zone, prompting opportunistic dyke intrusion and ultimately facilitating the eruption. A precipitation-induced eruption trigger is consistent with the lack of precursory summit inflation, showing that this intrusion-unlike others-was not caused by the forceful intrusion of new magma into the rift zone. Moreover, statistical analysis of historic eruption occurrence suggests that rainfall patterns contribute substantially to the timing and frequency of Kīlauea's eruptions and intrusions. Thus, volcanic activity can be modulated by extreme rainfall triggering edifice rock failure-a factor that should be considered when assessing volcanic hazards. Notably, the increasingly extreme weather patterns associated with ongoing anthropogenic climate change could increase the potential for rainfall-triggered volcanic phenomena worldwide.
Central-Southern Italy and the Tyrrhenian Sea are the sites of extensive Plio-Quaternary magmatic activity. The rock compositions include crustal anatectic granites and rhyolites, tholeiitic, ...calc-alkaline, shoshonitic volcanics, and potassic to ultrapotassic and Na-alkaline volcanics. This very wide compositional variation makes Italian magmatism one of the most complex petrological issues, the understanding of which is a challenge for modern petrology and geochemistry. This book summarises the petrological, geochemical and volcanological characteristics of Italian Plio-Quaternary volcanism, and discusses petrogenetic hypotheses and possible geodynamics settings. The book is written for petrologists and geochemists, but fundamental geochemical information is well presented and the use of excessive jargon is avoided, making the book readable to a wide audience of Earth scientists. The book is accompanied by a CD-ROM containing a database of volcanic rock analyses compiled in the last two to three decades.
The caldera collapse of Deception Island Volcano, Antarctica, was comparable in scale to some of the largest eruptions on Earth over the last several millennia. Despite its magnitude and potential ...for far-reaching environmental effects, the age of this event has never been established, with estimates ranging from the late Pleistocene to 3370 years before present. Here we analyse nearby lake sediments in which we identify a singular event produced by Deception Island's caldera collapse that occurred 3980 ± 125 calibrated years before present. The erupted tephra record the distinct geochemical composition of ejecta from the caldera-forming eruption, whilst an extreme seismic episode is recorded by lake sediments immediately overlying the collapse tephra. The newly constrained caldera collapse is now the largest volcanic eruption confirmed in Antarctica during the Holocene. An examination of palaeorecords reveals evidence in marine and lacustrine sediments for contemporaneous seismicity around the Antarctic Peninsula; synchronous glaciochemical volcanic signatures also record the eruption in ice cores spread around Antarctica, reaching >4600 km from source. The widespread footprint suggests that this eruption would have had significant climatic and ecological effects across a vast area of the south polar region.
Abstract
Measurements of volcanic tephra fallout deposits provide useful information about the magnitude and intensity of explosive volcanic eruptions and potential for remobilization of deposits as ...dangerous volcanic flows. However, gathering information in the vicinity of erupting craters is extremely dangerous, and moreover, it is often quite difficult to determine deposit thickness proximal to volcanic craters because the thickness of the deposit is too great to easily measure; thus, airborne remote sensing technologies have generally been utilized during the intermission between eruptions. As an alternative tool, a muographic tephra deposit monitoring system was developed in this work. Here we report the performance of this system by applying the muographic data acquired at Sakurajima volcano, Japan as an example. By assuming the average density of the deposit was 2.0 g cm
−3
, the deposit thicknesses measured with muography were in agreement with the airborne results, indicating that volcanic fallout built up within the upper river basin, showed its potential for monitoring the episodic tephra fallouts even during eruptions.
Mt. Spurr is the largest active volcano in Alaska of high explosive potential. The most recent activity, including two recent magmatic eruptions in 1953 and 1992, has occurred via the flanking Crater ...Peak. From 2004 to 2006, strong seismicity, gas flux, and heating were observed in the summit area, which had remained inactive for more than 5 Ka. To understand the cause of this reactivation, we performed repeated tomography inversions that clearly imaged the magma reservoir beneath Mt. Spurr and showed temporal changes in its shape and intensity. During the two years preceding the unrest, we observed ascension of the upper limit of the reservoir-related anomaly from a depth of 5 to 3 km below the surface, accompanied by strong seismicity. During the following years, the shape of the anomaly remained unchanged, but its intensity weakened. These observations may indicate the release of fluids from the ductile reservoir and fast upward ascent through the brittle cover that caused intensive seismicity and gas flux during the unrest from 2004 to 2006. The origin of this zone will possibly cause a resumption of explosive eruptions in the summit area of Mt. Spurr.
We present a detailed study of specific ion effects, volcano plots and the law of matching solvent affinities by means of a conceptual density functional theory (DFT) approach. Our results highlight ...that specific ion effects and the corresponding implications on the solvation energy are mainly due to differences in the electric chemical potentials and chemical hardnesses of the ions and the solvent. Our approach can be further used to identify reliable criteria for the validity of the law of matching solvent affinities. Basic expressions are derived, which allow us to study the limiting conditions for this empirical observation with regard to matching chemical reactivity indices. Moreover, we show that chaotropic and kosmotropic concepts and their implications for the stability of ion pairs are directly related to a generalized strong and weak acids and bases (SWAB) principle for ions in solution, which is also applicable to rationalize the shape of volcano plots for different solvents. In contrast to previous assumptions, all empirical findings can be explained by the properties of local solvent‐ion complexes which dominate the specific global behavior of ion pairs in solution.
Keep it local: We present a detailed study of specific ion effects and the law of matching solvent affinities by means of conceptual density functional theory calculations. Our results underline the strong influence of the solvent in combination with the electronic chemical potential and the chemical hardness of the species. Further analytical considerations shed light on the principles of ion pair formation and ion pair dissociation with regard to a new formulation within the framework of strong and weak acids and bases.
Searching for low-cost electrocatalysts with high activity towards the hydrogen evolution reaction (HER) is of great significance to enable large-scale hydrogen production via water electrolysis. In ...this study, by using inverse spinel MFe2O4(M = Mn, Fe, Co, Cu) nanoparticles (NPs) as the precursors, monodisperse bimetallic phosphide M-Fe-P NPs/C with hollow structures were readily obtained by a gas-solid annealing method. These hollow phosphide NPs displayed excellent HER activity in an acidic medium with a low loading amount of 0.2 mg cm−2. In particular, the Co–Fe–P NPs/C shows highest HER activity that only requiring an overpotential of 97 mV to retain a current density of 10 mA cm−2. A volcano relation between activity and incorporated elements was revealed. Incorporation of cation with high electronegativity stabilized the FeP active centres, while phase segregation resulted in the loss of activity for Cu–Fe–P NPs/C.
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•Hollow bimetallic phosphide NPs were prepared via a facile synthetic method.•The bimetallic phosphide NPs exhibited superior HER activity in acidic medium.•A volcano-type correlation between activity and doped cations was established.•Incorporation of cation with high electronegativity prevented FeP from oxidation.•Phase segregation of Cu3P resulted in inferior HER activity of Cu–Fe–P NPs/C.
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•The hot-water pretreatment can generate new Brønsted acid sites.•The hot-water pretreated H-MOR shows high activity for DME carbonylation.•The hot-water pretreated H-MOR accelerates ...the formation of methoxy groups.•The residue water molecules will inhibit DME carbonylation.
Herein, we report the effect of the hot-water pretreatment on the catalytic activity of the H-mordenite (H-MOR) zeolite for DME carbonylation. The structure and acidity of the H-MOR catalysts pretreated by hot water were systematically characterized by XRD, nitrogen adsorption, SEM, H2O-TPD, NH3-TPD, 1H NMR and NH3-DRIFTS technologies. With the increase of the duration of the hot-water pretreatment, the catalytic activity shows a volcano-type variation. The H-MOR catalyst pretreated by hot water for 10 min at 573 K displays the highest catalytic activity among all of the catalysts. The appropriate duration of the hot-water pretreatment can generate new medium strong and strong Brønsted acid sites, which changes the microenvironment in the pores of H-MOR. Additionally, the newly generated Brønsted acid sites will accelerate the first step of DME carbonylation, that is, DME reacts with the Brønsted acid sites of the zeolite forming surface methoxy groups and methanol, improving the catalytic activity of the catalysts. However, too long duration of the hot-water pretreatment will remain water molecules in H-MOR, which inhibits DME carbonylation.
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