Collaborative Research: Bridging the gap between long- and short- wavelength structure in the mantle

地球图像？S内部的图像主要由两种技术产生，在分辨率的两个末端提供地球的快照。(1)层析成像提供了地球的全地幔视图，S提供了大尺度(2000-5000公里)的地震速度异常；(2)波形模拟提供了特定地理位置的小尺度(约100-500公里)的视图。因为在这些成像技术中分辨出的特征的尺度长度不同于一个数量级，所以将这些不同的图像协调到一个地球模型中仍然是具有挑战性的--S内部。本项目旨在通过以下方式调和在这些图像中观察到的差异：(1)分析在北美记录的新的地震数据，这些地震数据来自Earthcope？S可移动阵列(TA)和FlexArray部署、ANSS主干站、加拿大国家地震台网和最近的PASSCAL部署；(2)利用PSVaxi软件通过全波形建模技术分析以前引入社区的全球和区域尺度模型。其主要目标是评估全球和区域尺度地震模型的准确性，并破译深部地幔在所有空间尺度上的复杂结构如何影响宽带地震波。深部地幔结构的地震学模拟对于理解地球内部发生的动态过程至关重要。该项目将进一步开发能够在全球范围内模拟地震运动的软件。最终，通过将模拟的波形与新记录的数据进行比较，这将有助于阐明地球-S的内部结构。他们将测试之前得出的地球模型的有效性，评估地幔深处的结构特征如何影响地震波形。最终，这将为社区提供有价值的波形传播工具和对地震模型和图像的准确性的严格评估。

Images of the Earth?s interior are primarily produced by two types of techniques providing snapshots of the Earth at two end-members of resolution. (1) Tomographic imaging provides a whole-mantle view of Earth?s large-scale ( 2000-5000 km) seismic velocity anomalies; (2) Waveform modeling provides a small-scale (~100-500 km) view for specific geographic locations. Because the scale length of features resolved in these imaging techniques varies by an order of magnitude it remains challenging to reconcile these different pictures into one single model of the Earth?s interior. This project aims to reconcile the disparities observed in these images by: (1) Analyzing new seismic data recorded in North America from Earthscope?s Transportable Array (TA) and FlexArray deployments, ANSS Backbone stations, Canadian National Seismic Network Stations, and recent PASSCAL deployments; (2) Analyzing global- and regional-scale models previously introduced to the community by full waveform modeling techniques using the PSVaxi software. The primary goals are to assess the accuracy of the global and regional scale seismic models, and to decipher how complex structures in the deep mantle at all spatial scales affect broadband seismic waveforms.Seismological modeling of deep mantle structure is crucial in understanding the dynamic processes taking place within the Earth. This project will further develop software that is capable of simulating earthquake motions on the global scale. Ultimately this will aid in elucidating the Earth?s interior structure by comparing the simulated waveforms with the newly recorded data. They will test the validity of previously derived Earth models, assessing how structural features in the deep mantle affect the seismic waveforms. Ultimately, this will provide valuable waveform propagation tools and a rigorous assessment of the accuracy of seismic models and images to the community.