• 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 >Subsidence of Askja caldera 2000-2009: Modelling of deformation processes at an extensional plate boundary, constrained by time series InSAR analysis
【24h】

Subsidence of Askja caldera 2000-2009: Modelling of deformation processes at an extensional plate boundary, constrained by time series InSAR analysis

机译：Askja Caldera 2000-2009的沉降：受时间序列InSAR分析约束的延伸板块边界处的变形过程建模

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

Many calderas in the world show long-term unrest in the form of elevated rates of deformation and seismicity, related to pressure changes and magma movements within their magmatic plumbing systems. We present new observations of the style of deformation at the Askja caldera, Iceland, since 2000, using interferometric analysis of synthetic aperture radar images (InSAR) acquired by the Canadian RADARSAT-2 satellite. When combined with previously acquired detailed geodetic observations, by various techniques, we obtain an overview of Askja's behaviour through more than four decades. The combined dataset reveals that, during this non-eruptive period, Askja continuously subsides at a rate of 2.5-3 cm/yr in 2000-2009, somewhat lower than the ～5 cm/yr rate inferred for the 1983-1998 period. This behaviour of Askja is evaluated and compared to those of other restless calderas. The wrapped interferograms show three main features: (1) concentric fringes depicting subsidence in the centre of the main Askja caldera, (2) oval fringes elongated along the rift portraying subsidence and (3) subsidence in an area north of the Vatnajoekull glacier. The average line-of-sight (LOS) velocity from ground to satellite was used as input for inverse modelling, of a deflating pressure source beneath the caldera, embedded in a homogeneous, elastic half-space. Two different source geometries were tested: a point pressure source and a horizontal penny shaped crack. The concentric fringes centred in the Askja caldera are best fit by a point source located at 65.05°N 16.78°W, at a depth of 3.2-3.8 km with a volume decrease of 0.0012-0.0017 km~3/yr from 2000 to 2009, consistent with previous studies. Provisional 2D FEM models including structural complexities in the crustal layers indicate that the tectonic setting of Askja plays an important role in the continuous, long-term high subsidence rates observed there. In order to fully understand the cause and effects of the complicated tectonic setting we encourage the use of a more realistic rheological model of the area, which could lead to reinterpretation of previous model results.
机译：世界上许多火山口都表现出长期动荡，形式是变形和地震活动率升高，与岩浆管道系统内的压力变化和岩浆运动有关。自2000年以来，我们使用加拿大RADARSAT-2卫星获取的合成孔径雷达图像（InSAR）的干涉测量分析，介绍了冰岛Askja火山口的变形样式的新观测结果。当与以前获得的详细的大地观测资料结合起来时，我们通过各种技术获得了超过40年的Askja行为概览。合并的数据集显示，在这个非喷发期，Askja在2000-2009年以2.5-3 cm / yr的速率连续消退，比1983-1998年推算的〜5 cm / yr的速率低一些。评估了Askja的这种行为，并将其与其他烦躁不安的破火山口的行为进行了比较。包裹的干涉图显示三个主要特征：（1）同心条纹，描绘了主要Askja破火山口中心的沉降；（2）椭圆形条纹沿裂谷描绘的沉降拉长；（3）沉降在Vatnajoekull冰川以北的地区。从地面到卫星的平均视线（LOS）速度被用作反演的输入，对破火山口下方的放气压力源进行了建模，该压力源嵌入均匀的弹性半空间中。测试了两种不同的源几何形状：点压力源和水平的便士形裂缝。从2000年到2009年，位于Askja破火山口中心的同心条纹最适合于65.05°N 16.78°W深度为3.2-3.8 km的点源，体积减少0.0012-0.0017 km〜3 / yr，与以前的研究一致。包括地壳层结构复杂性在内的临时二维有限元模型表明，Askja的构造环境在该处观测到的连续，长期高沉降率中起着重要作用。为了充分了解复杂构造环境的因果关系，我们鼓励使用该地区更现实的流变模型，这可能会导致对先前模型结果的重新解释。

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