نتایج جستجو برای: magma

تعداد نتایج: 7321  

2001
Kari M. Cooper Mary R. Reid Michael T. Murrell David A. Clague

Previous estimates of crustal storage time of magmas at Kilauea Volcano, Hawaii, range from a few years to a few thousand years, leading to considerable uncertainty in the time scales of processes of magmatic storage and differentiation. We present a new approach for determining minimum magma residence times which involves dating phenocrysts in a magma using 226Ra^230Th disequilibria, and apply...

2013
C. Plattner F. Amelung S. Baker R. Govers

[1] Multiple mechanisms have been suggested to explain seaward motion of the south flank of Kīlauea Volcano, Hawai‘i. The consistency of flank motion during both waxing and waning magmatic activity at Kīlauea suggests that a continuously acting force, like gravity body force, plays a substantial role. Using finite element models, we test whether gravity is the principal driver of long-term moti...

1997
D. S. Stevenson

The rates of passive degassing from volcanoes are investigated by modelling the convective overturn of dense degassed and less dense gas-rich magmas in a vertical conduit linking a shallow degassing zone with a deep magma chamber. Laboratory experiments are used to constrain our theoretical model of the overturn rate and to elaborate on the model of this process presented by Kazahaya et al. (19...

2013
D. Ferguson D. Ayalew A. Calvert

Crustal extension at mature continental rifts and oceanic ridges occurs by a combination of normal faulting and magma injection, which interact to create rift morphology. Quantifying the relative roles of faulting and melt intrusion in accommodating extension at magmatic rifts remains difficult and requires studies at sufficient spatial and temporal scales to resolve the interaction between the...

2017
M. Grace Bato Virginie Pinel Yajing Yan

In monitoring active volcanoes, the magma overpressure is one of the key parameters used in forecasting volcanic eruptions. This parameter can be inferred from the ground displacements measured on the Earth’s surface by applying inversion techniques. However, in most studies, the huge amount of information about the behavior of the volcano contained in the temporal evolution of the deformation ...

2006
E. M. Parmentier

Introduction: Volatile content of a planetary magma ocean has significant effects on the process of magma ocean solidification, on formation of an initial planetary atmosphere, and on subsequent mantle composition [1-5]. The heterogeneous partitioning of volatile phases during accretion and differentiation of the Earth and Mars can account for current volatile budgets without the need to invoke...

2007
LIONEL WILSON

Geological and physical observations and constraints are applied to the development of a model of the ascent and emplacement of basaltic magma on the earth and moon. Mathematical models of the nature and motion of gas/liquid mixtures are developed and show that gas exsolution from terrestrial and lunar magmas commonly only occurs at shallow depths (less than 2 km); thus the ascent of bubble-fre...

2008

Volcano monitoring uses knowledge of volcanic processes and extensive data gathering to analyze areas of volcanic activity. The main goal is to learn the nature of the volcano, the magmatic processes occurring, and the likelihood of a future eruption. Volcano monitoring centers around three aspects of volcanic processes: ground deformation, seismic activity, and gas emissions. These techniques ...

2010
AXEL K. SCHMITT FLORIAN WETZEL KARI M. COOPER HAIBO ZOU

Uranium-series dating of carbonatitic ejecta clasts constrains the crystallization and differentiation timescales of the Laacher See volcano, which erupted 6·3 km of magma (dense rock equivalent) during one of the largest Late Quaternary eruptions in Central Europe. Carbonatites form a distinct population among plutonic ejecta that are present in the middle and late erupted Laacher See tephra. ...

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