...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Volcanology and Geothermal Research >Structural and rheological constraints on source depth and overpressure estimates at the Campi Flegrei caldera, Italy
【24h】

Structural and rheological constraints on source depth and overpressure estimates at the Campi Flegrei caldera, Italy

机译：意大利Campi Flegrei破火山口的构造和流变学对震源深度和超压估算的限制

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

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 (～3 km). If the source radius is ～ 1 km, this implies that magma is at a depth of ～ 2 km depth. However, several independent observations show that the top of the magma chamber at CF must be deeper than ? 4 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 ～ 5 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.
机译：1982-1984年意大利Campi Flegrei（CF）破火山口的骚动事件集中在破火山口内部，变形巨大（超过1.5 m隆起）。根据均质弹性和粘弹性半空间中的点源各向同性模型，源深度很浅（〜3 km）。如果源半径为〜1 km，则表明岩浆深度为〜2 km。但是，一些独立的观察表明，位于CF处的岩浆室顶部必须比Φ？深。 4公里本文研究了当考虑刚性异质性（通过CF地震层析成像法获得）以及在排水条件下发生长期变形时，推断的震源深度如何增加。有限元模型表明，重现1.5 m最大隆起所需的源超压超出了典型的岩石强度值。该证据以及高热异常，流体的存在和填充火山口的凝灰岩的低内聚力，表明使用了弹塑性本构法。对于弹塑性行为，使用更深的震源（中心在〜5 km深度）和较低的超压（比弹性模型要求的压力低）可获得相同的变形。塑性变形既集中在震源边界，又集中在震源上方，记录了地震活动。这些结果表明，CF浅层壳的流变特性对动乱期间的危险性估计具有重要意义。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号