-
- Eleonora Rivalta
- Department of Physics University of Bologna Bologna Italy.
-
- Paul Segall
- Department of Geophysics Stanford University Stanford California USA.
書誌事項
- 公開日
- 2008-02
- 権利情報
-
- http://onlinelibrary.wiley.com/termsAndConditions#vor
- DOI
-
- 10.1029/2007gl032521
- 公開者
- American Geophysical Union (AGU)
この論文をさがす
説明
<jats:p>Dike intrusions are often accompanied by localized deflation, interpreted as depressurizing magma chambers feeding the dike. In some cases the inferred volume decrease is a factor of 4 or 5 less than the volume increase of the dike. Here we explore whether this discrepancy can be explained by compressibility of the magma combined with the fact that cracks are much more compliant than equidimensional magma chambers. If pressure changes are small, the magma compressibility <jats:italic>β</jats:italic><jats:sub><jats:italic>m</jats:italic></jats:sub> is constant, and the dike ends up in hydrostatic equilibrium with an ellipsoidal magma chamber at the same depth, the ratio <jats:italic>r</jats:italic><jats:sub><jats:italic>V</jats:italic></jats:sub> of the volume of the crack to the volume lost by the chamber is <jats:italic>r</jats:italic><jats:sub><jats:italic>V</jats:italic></jats:sub> = 1 + 4<jats:italic>μβ</jats:italic><jats:sub><jats:italic>m</jats:italic></jats:sub>/3 > 1, where <jats:italic>μ</jats:italic> is the host rock rigidity. For gas poor magmas, <jats:italic>β</jats:italic><jats:sub><jats:italic>m</jats:italic></jats:sub> = 0.6–2 · 10<jats:sup>−10</jats:sup> Pa<jats:sup>−1</jats:sup> and <jats:italic>μ</jats:italic> = 3–25 GPa, we find 1.2 < <jats:italic>r</jats:italic><jats:sub><jats:italic>V</jats:italic></jats:sub> < 7.7. Large changes in magma compressibility due to gas exsolution increase <jats:italic>r</jats:italic><jats:sub><jats:italic>V</jats:italic></jats:sub>.</jats:p>
収録刊行物
-
- Geophysical Research Letters
-
Geophysical Research Letters 35 (4), L04306-, 2008-02
American Geophysical Union (AGU)
