Development and Application of the Back-Projection Techinque for Detailed Earthquake Rupture Modelling

该项目评估从地震阵列数据的反投影获得的地震特性的鲁棒性和分辨率，并检查提高成像能力的方法。破裂模型，特别是它的速度和持续时间，是预测地面运动的主要成分之一。 它也是研究地震发生、传播和终止的物理学的一个关键因素。尽管如此重要，破裂模型目前可用于有限数量的充分研究的事件，如1992年兰德斯，加州地震。大量高质量的数据，从密集的地震阵列介绍了一个机会，解开详细的地震破裂过程，和反投影分析可能会导致一个目录的能量辐射和传播模型。 该方法可应用于任何阵列，但本项目的重点是来自日本高灵敏度地震仪网络的数据。 该方法的应用，这一数据集提供了限制属性，如2004年苏门答腊-安达曼和2005年尼亚斯地震的范围和持续时间。 虽然这些结果证明了该技术的强大功能和高质量的阵列数据，但该方法对其他地震的不确定性和适用性的估计尚未得到充分探讨。 本项目针对这些问题，并探讨改善反投影程序的策略。 该项目的目的是使我们对该方法的能力和局限性的理解正规化，并通过在接近真实的时间内检测和表征地震来确定其在减灾方面的可行性。 更广泛的影响包括对研究生和本科生的支持和教育。

This project evaluates the robustness and resolution of earthquake properties obtained from back-projection of seismic array data, and examines methods for improving the imaging ability. A rupture model, especially its speed and duration, is one of the main ingredients for predicting ground motion. It is also a key factor in studies of the physics of earthquake initiation, propagation, and termination. Despite such importance, rupture models are currently available for a limited number of well-studied events such as the 1992 Landers, California earthquake. A large number of high-quality data from a dense seismic array introduces an opportunity for unraveling detailed earthquake rupture processes, and the back-projection analysis can potentially lead to a catalog of energy radiation and propagation models. The method could be applied to any array, but this project focuses on data from the High Sensitivity Seismograph Network in Japan. Application of the method to this data set has provided constraints on properties such as extent and duration of the 2004 Sumatra-Andaman and 2005 Nias earthquakes. While these results demonstrate the power of the technique and high-quality array data, the estimates of uncertainty and applicability of the method to other earthquakes have not been fully explored. This project addresses these issues, and investigates strategies for improving the back-projection procedure. The aim of the project is to formalize our understanding of the capability and limitations of the method as well as determining its feasibility in hazard mitigation through detection and characterization of earthquakes in near real time. Among the broader impacts are the support and education of a graduate student and an undergraduate.