A critical magma chamber size for volcanic eruptions

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 431-435 ◽  
Author(s):  
Meredith Townsend ◽  
Christian Huber
Keyword(s):  
Magma Chamber ◽  
Scaling Law ◽  
Volcanic Eruptions ◽  
Elastic Response ◽  
Chamber Pressure ◽  
Pressure Drops ◽  
Chamber Volume ◽  
Intermediate Chamber ◽  
History Of ◽  
Chamber Size

Abstract We present a model for a coupled magma chamber–dike system to investigate the conditions required to initiate volcanic eruptions and to determine what controls the size of eruptions. The model combines the mechanics of dike propagation with internal chamber dynamics including crystallization, volatile exsolution, and the elastic response of the magma and surrounding crust to pressure changes within the chamber. We find three regimes for dike growth and eruptions: (1) below a critical magma chamber size, eruptions are suppressed because chamber pressure drops to lithostatic before a dike reaches the surface; (2) at an intermediate chamber size, the erupted volume is less than the dike volume (“dike-limited” eruption regime); and (3) above a certain chamber size, dikes can easily reach the surface and the erupted volume follows a classic scaling law, which depends on the attributes of the magma chamber (“chamber-limited” eruption regime). The critical chamber volume for an eruption ranges from ∼0.01 km3 to 10 km3 depending on the water content in the magma, depth of the chamber, and initial overpressure. This implies that the first eruptions at a volcano likely are preceded by a protracted history of magma chamber growth at depth, and that the crust above the magma chamber may have trapped several intrusions or “failed eruptions.” Model results can be combined with field observations of erupted volume, pressure, and crystal and volatile content to provide tighter constraints on parameters such as the eruptible chamber size.

scholarly journals The dynamics of dual-magma-chamber system during volcanic eruptions inferred from physical modeling

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Tomofumi Kozono
Keyword(s):  
Analytical Solution ◽  
Magma Chamber ◽  
Volcanic Eruptions ◽  
Chamber Pressure ◽  
Deformation Pattern ◽  
Chamber System ◽  
Plumbing System ◽  
Magma Chambers ◽  
Magma Flow ◽  
Magma Plumbing System

AbstractA magma plumbing system with dual magma chambers beneath active volcanoes is commonly observed through petrological and geophysical measurements. This paper developed a physical model for the dynamics of a dual-magma-chamber system during volcanic eruptions. The model consists of the plumbing system where two elastically deformable magma chambers are connected in series with non-deformable conduits. Based on this model, we obtained an analytical solution that describes temporal changes in pressures at the two chambers accompanied by the eruption. The analytical solution showed that the feature of the chamber pressure changes is mainly controlled by two non-dimensional numbers $$C'$$ C ′ and $$\Omega '$$ Ω ′ . Here, $$C'$$ C ′ is the ratio of the parameter controlling the magnitude of pressure change in the shallower chamber to that in the deeper chamber, and $$\Omega '$$ Ω ′ is the ratio of conduit’s conductivity (inverse of resistivity to magma flow) between the shallower chamber and the surface to that between the chambers. For smaller $$C'$$ C ′ and $$\Omega '$$ Ω ′ , the shallower chamber’s pressure is kept constant during the decrease in the pressure at the deeper chamber in the initial phase of the eruption. This corresponds to a deformation pattern commonly observed in some eruptions, in which the deflation of the deeper chamber was predominant. The estimation of $$C'$$ C ′ and $$\Omega '$$ Ω ′ based on the parameters related to magma properties and geometries of the chambers and the conduits revealed that the smaller $$C'$$ C ′ and $$\Omega '$$ Ω ′ conditions are satisfied under realistic magmatic and geological parameters. This indicates that the magma dynamics in the dual-chamber system generally cause the dominance of the deeper chamber’s deflation.

scholarly journals The Earliest History of the Skaergaard Magma Chamber: a Textural and Geochemical Study of the Cambridge Drill Core

2015 ◽  
Vol 56 (6) ◽  
pp. 1199-1227 ◽  
Author(s):  
Marian B. Holness ◽  
Christian Tegner ◽  
Olivier Namur ◽  
Llewellyn Pilbeam
Keyword(s):  
Magma Chamber ◽  
Drill Core ◽  
Geochemical Study ◽  
History Of

Cage size and flight speed of the tobacco hawkmoth Manduca sexta

1995 ◽  
Vol 198 (8) ◽  
pp. 1665-1672 ◽  
Author(s):  
R Stevenson ◽  
K Corbo ◽  
L Baca ◽  
Q Le
Keyword(s):  
Manduca Sexta ◽  
Flight Speed ◽  
Flight Behavior ◽  
Cube Root ◽  
The Third ◽  
Chamber Volume ◽  
Cage Size ◽  
Allometric Analysis ◽  
Size Limits ◽  
Chamber Size

Flight speeds and behaviors of the sphinx moth Manduca sexta were recorded in chambers of four different sizes (0.57, 8.5, 44 and 447 m3). Mean horizontal speed increased linearly with the cube root of chamber volume from 0.57 m s-1 in the smallest chamber to 3.4 m s-1 in the largest. The maximum horizontal speed observed was 5.3 m s-1 in the largest chamber. Speeds decreased linearly with the logarithm of hawkmoth proximity to the wall. In a tunnel chamber (the third largest), moths often flew in a scalloped-shaped path. At the top of the scallop, they glided for 1­5 wing beats. In the largest chamber, moths could be recorded flying at angles other than horizontal (0 °). At flight angles greater or less than 0 °, mean speed decreased linearly with angle until ±40 °. At greater angles, speeds remained between 1 and 2 m s-1. Moths also flew closer to the wall at flight angles deviating from the horizontal. An allometric analysis of the flight speeds of insects and birds suggests that M. sexta may be able to fly at 7­10 m s-1. We conclude that chamber size limits the flight speed and modifies the flight behavior of the tobacco hawkmoth.

Assessment of Fiber Strength in a Urinary Bladder by Using Experimental Pressure Volume Curves: An Analytical Method

1986 ◽  
Vol 108 (4) ◽  
pp. 301-305 ◽  
Author(s):  
A. To¨zeren
Keyword(s):  
Urinary Bladder ◽  
Analytical Method ◽  
Fiber Strength ◽  
Rate Of Change ◽  
Chamber Pressure ◽  
Fiber Stress ◽  
Chamber Volume ◽  
Volume Relation ◽  
Fiber Reinforced Material ◽  
Biochemical Activation

In the present study, an analytical method is developed to deduce the constitutive equations of fibers embedded in a thick shell from the time-variant pressure volume curves obtained by experimental procedures. It is assumed that the spherical shell under consideration is composed of a fiber reinforced material and undergoes radial deflection, modeling the behavior of some biological shells such as urinary bladder. The fiber stress is expressed as a function of fiber strain, rate of strain and the degree of biochemical activation. The function form is chosen such that equations of mechanical equilibrium can be integrated analytically to yield chamber pressure as a function of chamber volume, time rate of change of volume and activation. Arbitrary coefficients appearing in the fiber stress-equation are also present in the resultant time-variant pressure-volume relation. These coefficients can be determined by curve-fitting commonly used clinical data such as cystometry measurements.

Late Quaternary vegetation of the Aleutian Islands, southwestern Alaska

1990 ◽  
Vol 68 (6) ◽  
pp. 1320-1326 ◽  
Author(s):  
Calvin J. Heusser
Keyword(s):  
Late Quaternary ◽  
Thickness Distribution ◽  
Patch Dynamics ◽  
Volcanic Eruptions ◽  
Ice Age ◽  
Aleutian Islands ◽  
Fossil Pollen ◽  
History Of ◽  
Tephra Layers ◽  
Radiocarbon Chronology

Late Quaternary vegetational history of the Aleutian Islands is interpreted from fossil pollen and spore stratigraphy and radiocarbon chronology of sections of mires on the islands of Attu, Adak, Atka, and Umnak. Mires postdate the withdrawal of ice-age glaciers between approximately 12 000 and 10 000 years ago with the exception of the mire on Attu Island, where deglaciation apparently began as late as 7000 years ago. No uniform pattern of change in Pacific coastal tundra communities is evident in the fossil assemblages. Pollen assemblages, consisting variably of Gramineae, Cyperaceae, Empetrum, Umbelliferae, Salix, Ranunculaceae, Compositae, Polypodiaceae, and Lycopodium, reflect conditions in effect in different sectors of the Aleutian chain. Climate, soil, topography, volcanism, and seismic activity are noteworthy parameters influencing vegetation composition and distribution. Volcanism has been of major importance, as shown by thickness, distribution, and frequency of tephra layers that number 5 on Attu, 24 on Adak, 17 on Atka, and 5 on Umnak. A repeated condition of patch dynamics, created in the main by recurrent volcanic eruptions with widespread accompanying ashfalls, has apparently overprinted the effects of climatic change. Key words: Aleutian Islands, Quaternary, vegetation, fossil pollen, volcanism.

scholarly journals Scaling properties of planetary calderas and terrestrial volcanic eruptions

2012 ◽  
Vol 19 (6) ◽  
pp. 585-593 ◽  
Author(s):  
L. Sanchez ◽  
R. Shcherbakov
Keyword(s):  
Solar System ◽  
Scaling Law ◽  
Geographical Location ◽  
Internal Heat ◽  
Volcanic Eruptions ◽  
Scaling Analysis ◽  
Scaling Properties ◽  
Caldera Formation ◽  
Planetary Bodies ◽  
Terrestrial Planetary Bodies

Abstract. Volcanism plays an important role in transporting internal heat of planetary bodies to their surface. Therefore, volcanoes are a manifestation of the planet's past and present internal dynamics. Volcanic eruptions as well as caldera forming processes are the direct manifestation of complex interactions between the rising magma and the surrounding host rock in the crust of terrestrial planetary bodies. Attempts have been made to compare volcanic landforms throughout the solar system. Different stochastic models have been proposed to describe the temporal sequences of eruptions on individual or groups of volcanoes. However, comprehensive understanding of the physical mechanisms responsible for volcano formation and eruption and more specifically caldera formation remains elusive. In this work, we propose a scaling law to quantify the distribution of caldera sizes on Earth, Mars, Venus, and Io, as well as the distribution of calderas on Earth depending on their surrounding crustal properties. We also apply the same scaling analysis to the distribution of interevent times between eruptions for volcanoes that have the largest eruptive history as well as groups of volcanoes on Earth. We find that when rescaled with their respective sample averages, the distributions considered show a similar functional form. This result implies that similar processes are responsible for caldera formation throughout the solar system and for different crustal settings on Earth. This result emphasizes the importance of comparative planetology to understand planetary volcanism. Similarly, the processes responsible for volcanic eruptions are independent of the type of volcanism or geographical location.

THE EARLY AND MIDDLE BRONZE AGE SETTLEMENT AT KOIMISIS, THERASIA: PERIODS OF HABITATION AND ARCHITECTURE

2020 ◽  
Vol 115 ◽  
pp. 105-132
Author(s):  
Kostas Sbonias ◽  
Iris Tzachili ◽  
Maya Efstathiou ◽  
Clairy Palyvou ◽  
Costas Athanasiou ◽  
...  
Keyword(s):  
Bronze Age ◽  
Volcanic Eruptions ◽  
Geological Structure ◽  
Archaeological Investigation ◽  
New Information ◽  
Surface Survey ◽  
History Of ◽  
Geophysical Investigations ◽  
Middle Bronze Age ◽  
Early Phases

The study of the history of the first excavations on prehistoric Therasia in the nineteenth century, which were carried out in the context of contemporary scientific interest in the volcanic eruptions of Santorini, has led to the systematic archaeological investigation of the island from 2007 onwards. The intensive archaeological surface survey, the geological survey of the geological structure and palaeotopography of Therasia, and geophysical investigations, undertaken in conjunction with the ongoing excavation of the prehistoric settlement at the site of Panaghia Koimisis at the southern end of modern Therasia, have created the conditions for a more comprehensive approach to the archaeological landscape of the island. Based on the results from the excavation trenches in the south and south-east terraces of the Koimisis hill, which have been excavated down to the virgin soil, we present findings on the organisation, architecture and habitation phases of the Koimisis settlement. The site emerges as an important settlement located on the imposing hilltop rising on the west side of the pre-eruption Santorini caldera in the Early Bronze Age, with a long period of habitation to the end of the Middle Cycladic period, when it was definitively abandoned. The excavation of the settlement provides new information on its architecture and spatial organisation during the Early and Middle Bronze Age, completing the picture from Akrotiri, whose early phases are preserved in a piecemeal fashion under the buildings of the Late Cycladic town.

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