U.S.-Mexico Collaborative Research; Study of Benioff Zone Geometry and Stresses at the Tehauntepec, Mexico Transition Zone along the Middle America Trench

该奖项将支持卡伦教授之间的合作研究 圣克鲁斯大学的麦克纳利和哥伦比亚大学的冈萨雷斯-鲁伊斯博士 科学研究和上级教育中心 Ensenada（CISECE）在墨西哥。 最近的研究集中在 中等深度地震活动，从应力和几何形状来看， 与俯冲过程有关。 证据已经找到 这表明俯冲板块在某些位置“撕裂”成了板块 无论是在沟槽的几何形状或倾斜的急剧变化 下行板块或两者。 其他证据表明， 板是高度可变形的。 调查人员计划延长 目前的研究，包括详细研究的结构， 在特万特佩克过渡带的科科斯板块俯冲 墨西哥 该区域之所以令人感兴趣，是因为除其他原因外， 可能是科科斯-北 美洲-加勒比海板块;它是过渡浅角 和陡角俯冲;火山几何形状，海沟深度，板块 年龄和其他特征在这个位置发生变化;这是一个地震空区 断层机制与地震活动性 与墨西哥其他地区的分布有很大不同。 研究人员将使用观察方法， 非常准确的深度和区域地震的震源机制， 合成波形建模 根据这些地震数据， 几何形状和应力的性质和方向以及 以及上覆和下行板块内的位置。 这项工作将导致一个重要的出版物有关地震 机制、构造格架和地震危险性。

This award will support collaborative research between Prof. Karen McNally of the University of Santa Cruz and Dr. J. Gonzalez-Ruiz of the Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (CISECE) in Mexico. Recent studies have focused on intermediate depth seismicity, looking at the stresses and geometries associated with subduction processes. Evidence has been found suggesting that subducting plates "tear" into segments at locations of sharp changes in either the geometry of the trench or the dip of the downgoing plate or both. Other evidence suggests that downgoing plates are highly deformable. The investigators plan to extend present studies to include a detailed study of the structure of the subducting Cocos plate at the Tehuantepec transition zone beneath Mexico. This region is of interest because, among other reasons, it may be the location of the triple junction between the Cocos-North America-Caribbean plates; it is transitional between shallow angle and steep angle subduction; volcano geometry, trench depth, plate age, and other features change at this location; it is a seismic gap with unknown potential; and fault mechanism and seismicity distribution change markedly from those of other areas of Mexico. The investigators will use an observational approach by assembling very accurate depths and focal mechanisms of regional earthquakes via synthetic waveform modeling. Based on this earthquake data set, the geometry and the nature and direction of stress and coupling between and within the overriding and downgoing plates will be determined. The work will lead to a significant publication regarding earthquake mechanisms, tectonic framework, and seismic risk.