Stochastic modeling of seismic wave propagation beneath island-arcs and volcanoes

岛弧和火山下地震波传播的随机模拟

• 批准号: 5352571
• 负责人: Professor Dr. Michael Korn
• 金额: --
• 依托单位: Institut für Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2002
• 资助国家: 德国
• 起止时间: 2001-12-31 至 2005-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5352571?language=en
• 关键词: Stochastic; modeling; seismic; wave; propagation

The crust and the upper mantle beneath island arcs and volcanoes are known to be very heterogeneous. The structural inhomogeneity including the fine structure of the subducting oceanic slab and the mantle wedge has been revealed from velocity tomography analyses. This method, which is based on the travel time reading of P and S wave onsets, disregards waveform information completely. Even though the spatial resolution of the velocity inhomogeneity has been improved recently by using data of new dense seismic networks, it is inherently difficult for this analysis to image short wavelength heterogeneities with scale length much shorter than the station separation. In contrast to the deterministic approach, there is an alternative, stochastic approach. The objective of this project is to propose theoretical models to explain wave propagation through highly inhomogeneous media and to develop methods for analyzing high frequency seismograms observed in island arcs and volcanoes. We use both analytical methods and numerical methods for the study of wave propagation in randon media, where we introduce a statistical treatment of the wave equation. Existing methods will be further developed in cooperation with our Japanese research partners of Tohoku University, and sample data sets from Merapi volcano will be studied.

众所周知，岛弧和火山下方的地壳和上地幔是非常不均匀的。速度层析分析揭示了俯冲洋板和地幔楔体的精细结构的结构不均一性。该方法以P波和S波初始走时读数为基础，完全不考虑波形信息。尽管最近利用新的密集地震台网资料提高了速度不均匀性的空间分辨率，但这种分析本身就很难成像尺度长度远小于台站间距的短波长非均质性。与确定性方法不同的是，还有一种替代的随机方法。该项目的目标是提出解释波在高度不均匀介质中传播的理论模型，并开发分析在岛弧和火山中观测到的高频地震图的方法。我们用解析方法和数值方法研究了波在随机介质中的传播，引入了对波动方程的统计处理。我们将与东北大学的日本研究伙伴合作，进一步发展现有的方法，并研究默拉皮火山的样本数据集。