کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9531121 | 1638495 | 2005 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Structural and rheological constraints on source depth and overpressure estimates at the Campi Flegrei caldera, Italy
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
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چکیده انگلیسی
The 1982-1984 unrest episode at Campi Flegrei (CF) caldera, Italy, was characterized by huge deformation (more than 1.5 m uplift) concentrated inside the caldera. According to point source isotropic models in homogeneous elastic and visco-elastic half-spaces, the source depth is very shallow (â¼3 km). If the source radius is â¼1 km, this implies that magma is at a depth of â¼2 km depth. However, several independent observations show that the top of the magma chamber at CF must be deeper than â¼4 km. This paper investigates how the inferred source depth increases when rigidity heterogeneities (obtained through seismic tomography at CF) are considered and when the long-term deformation takes place under drained conditions. Finite element models indicate that overpressure needed at the source to reproduce the 1.5 m maximum uplift is however beyond typical rock strength values. This evidence, together with the high thermal anomalies, the presence of fluids and the low cohesion of tuffs filling the caldera, suggests the use of elasto-plastic constitutive laws. For elasto-plastic behavior, the same deformation is obtained using a deeper source (with center at â¼5 km depth) and a lower overpressure (than required by elastic models). The plastic deformation concentrates both at the source boundaries and above the source, where seismic activity has been recorded. These results indicate that the rheological properties of the shallow crust of CF have important implications for hazard estimate during unrest episodes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Volcanology and Geothermal Research - Volume 144, Issues 1â4, 15 June 2005, Pages 105-118
Journal: Journal of Volcanology and Geothermal Research - Volume 144, Issues 1â4, 15 June 2005, Pages 105-118
نویسندگان
E. Trasatti, C. Giunchi, M. Bonafede,