Mapping Lithospheric Structure Beneath the Andes from Telesismic Analysis of Depth Phase Precursors

PIS将使用由地球望远镜的USArray组件以及全球地震台网(GSN)的适当台站收集的地震数据来探测南美洲安第斯山脉带下的地壳和上地幔。本研究基于？Underside？的使用。反射信号可能会在深度相PP之前到达，以识别和绘制关键的岩石圈不连续面，包括但不限于莫霍面、黑尔不连续面、岩石圈底部和可能的岩浆体。PP前体是目前唯一可获得的关于安第斯山脉关键地区这种不连续的存在、程度和性质的信息。它们还为常规地震信息(例如折射、层析成像、接收器功能)可用地区的这些特征提供了一个新的视角。通过分析传统技术中存在大量数据的地区的数据，我们希望改进我们的方法。更重要的是，这些观测应为各种地球动力学模型提供新的检验，这些模型已被提出将地壳增厚、构造缩短、高原隆起、岩石圈拆沉和沿安第斯类型边缘的火山作用联系起来。安第斯造山带是全球无碰撞造山的典范。因此，它被广泛引用为许多塑造北美西部的过程的现代类比。因此，我们提议的研究不仅应该促进我们对安第斯山脉的理解，而且可以延伸到对美国西部构造的新的洞察。由于这项技术在某种程度上仍然是探索性的，PI将把努力集中在最有利可图的方向上，特别强调使用最大的地震作为震源，并致力于叠加技术。他们希望演示一些处理过程，并走上获得一流结果的道路。这里开发/应用的方法不仅代表了在美国以外使用EarthScope设施探测岩石圈结构的相对新颖的用途，而且它构成了地震和勘探地震方法的结合，应该会被证明对研究世界上其他可获得深源地震源的地区很有用。这一奖项支持的研究生代表了连接主动和被动地震文化的培训。这种类型的整合肯定会成为未来地震研究的一个标志。

The PIs will use seismic data collected by the USArray component of EarthScope as well as appropriate stations of the Global Seismic Network (GSN) to probe the crust and upper mantle beneath the Andean mountain belt of South America. This research is based on the use of ?underside? reflected signals which may arrive ahead of the depth phase pP to identify and map key lithospheric discontinuities, including but not limited to the Moho, the Hale discontinuity, the base of the lithosphere and possible magma bodies. pP precursors represent the only currently available information about the existence, extent and nature of such discontinuities in key areas of the Andes. They also offer a new perspective on these features in areas where more conventional seismic information is available (e.g. refraction, tomography, receiver functions). By analyzing data from regions where substantial data exist from conventional techniques, we hope to refine our methodology. More importantly, these observations should provide new tests of the various geodynamic models which have been proposed to relate crustal thickening, tectonic shortening, plateau uplift, lithospheric delamination and volcanism along Andean-type margins. The Andean orogenic belt is the global archetype of non-collisional mountain building. As such it has been extensively cited as hosting the modern analogs for many of the processes that have shaped western North America. Thus our proposed research should not only advance our understanding of the Andes, but by extension provide new insight into the tectonics of the western US.As the technique is still exploratory to some degree, the PIs will focus efforts in the most profitable directions with particular emphasis on using the largest earthquakes as sources and working on the stacking techniques. They hope to demonstrate some of the processing and be on the road to obtaining first order results.The methodology to be developed/applied here not only represents a relatively novel use of EarthScope facilities to probe lithospheric structure outside the U.S., it constitutes a merger of earthquake and exploration seismic methodologies that should prove useful in studying other regions of the world where deep seismic sources are available. The graduate student to be supported by this award represents training that bridges the active and passive seismic cultures. This type of integration is sure to become a hallmark of future seismological investigations.