Collaborative Research: Superior Province Rifting Earthscope Experiment (SPREE)

这些研究人员与研究生和本科生沿着，正在从EarthScope Flexible Array池中安装83个宽带地震站，以探索中大陆裂谷系（MCRS）的深层结构。MCRS是一个广泛的裂谷事件的化石遗迹，未能在中元古代分裂北美。这一事件留下了大量致密的玄武岩和相关的强烈的地球物理异常。通过对裂谷下方的深层结构进行成像，这项地震实验研究了这些裂谷是如何形成和消亡的，而不是发展成为海洋扩张中心。地震台站位于断裂的裂谷周围，穿过断裂的裂谷，沿着断裂的裂谷，从明尼苏达州和爱荷华州的边界进入加拿大的上级湖。将通过接收器函数偏移、环境噪声分析、地震面波频散分析、区域S波和面波列拟合、地震到达时间层析成像、现有地震反射折射数据的再分析和SKS分裂分析，对MCRS中心部分的深层地震结构进行成像。这些分析结合成一个多分辨率，三维图像的各向同性和各向异性结构的地壳和地幔下的MCRS及其周围地区。这些分析的结果将阐明地幔在裂谷过程中的作用及其开始和结束。研究结果也将增进我们对大陆中部地震的了解。该研究项目至少雇用三名研究生，也涉及本科生，并促进来自加拿大和美国的研究人员之间的合作。

These investigators, along with graduate and undergraduate students, are installing 83 broadband seismic stations from the EarthScope Flexible Array pool to explore the deep structure of the Mid-Continent Rift System (MCRS). The MCRS is the fossil remnant of an extensive rifting event that failed to split North America during the Middle-Proterozoic era. This event left a large volume of dense basalts and associated strong geophysical anomalies. By imaging the deep structure beneath the rift, this seismic experiment investigates how such rifts form and then die, rather than developing into oceanic spreading centers. The seismic stations are located around, across, and along the failed rift, from the Minnesota-Iowa border into Canada by Lake Superior. Imaging the deep seismic structure of a central part of the MCRS will be undertaken with receiver function migration, ambient noise analysis, teleseismic surface wave dispersion analysis, regional S- and surface wave-train fitting, teleseismic arrival time tomography, re-analysis of existing seismic reflection & refraction data, and SKS-splitting analysis. These analyses are combined into a multi-resolution, three-dimensional image of the isotropic and anisotropic structure of the crust and mantle beneath the MCRS and its surroundings. Results of these analyses will illuminate the role of the mantle in the rifting process and its initiation and cessation. The results will also enhance our understanding of mid-continental earthquakes. This research project employs at least three graduate students, also involves undergraduate students, and fosters collaboration between researchers from Canada and the USA.