US-Switzerland Cooperative Research: Seismic Modeling of Reflective Structures in the Alps and Implications for Orogenic Structure

该奖项支持康奈尔大学的Larry Brown教授等人与日内瓦大学岩石物理实验室的Jean-Jacques Wagner教授和洛桑大学地球物理研究所的Raymond Oliver教授在地球物理领域的合作。他们联合研究的目的是在瑞士国家科学基金会的支持下，通过计算机模拟瑞士研究人员最近在阿尔卑斯山收集的深部地震数据，开发新的、更详细的造山带构造地质模型。暴露、彻底的测绘、多条地震线的可用性和构造历史的结合，使阿尔卑斯山可能是最有希望对反射剖面揭示的造山带深部结构进行更多定量比较研究的起点。随后，瑞士的结果将与美国古生代和前寒武纪造山带的类似深部结构进行比较，这是康奈尔大学代表COCORP（大陆反射剖面联盟）运作的一个多机构深层地震项目进行的调查。深地震反射剖面已成为研究地壳结构的标准工具。然而，关于深反射的实际原因的争论仍在继续。这一领域的一个重要发展是最近在年轻山带进行的地震调查，其中a)构造暴露得特别好，b)反射模式可以追溯到相当深的地方。阿尔卑斯系统也许是这种系统的最好的例子。瑞士人对已知高山构造的初步三维地震建模及其对深度的推断已被证明是一种有效的解释工具，可以对该活跃区域的假设构造进行定量测试。通过类比，在深层构造解释更为神秘的更古老的山带的地壳结构上可能会有相当大的启示。因此，这项工作可能会使阿尔卑斯山成为洲际碰撞的原型，并成为校准其他地方深地震反射数据的实验室。

This award supports Professor Larry Brown and others of Cornell University to collaborate in geophysics with Professor Jean-Jacques Wagner of the Laboratory of Petrophysics, University of Geneva, and Professor Raymond Oliver, Institute of Geophysics, University of Lausanne. The objective of their joint research is to develop new, more detailed geologic models of orogenic structure by computer modeling of deep seismic data recently collected across the Alps by the Swiss researchers, with support from the Swiss National Science Foundation. The combination of exposure, thorough mapping, availability of multiple seismic lines, and tectonic history make the Alps perhaps the most promising starting point for more quantitative comparative studies of deep structure of orogens as revealed from reflection profiling. Later, the Swiss results will be compared with similar deep structures in Paleozoic and Precambrian orogenic belts in the U.S., which were surveyed under a multi-institutional deep seismic program operated by Cornell University on behalf of COCORP (the Consortium for Continental Reflection Profiling.) Deep seismic reflection profiling has become a standard tool in the investigation of crustal structure. Yet debate persists concerning the actual cause of deep reflectivity. An important development in this field is the relatively recent acquisition of seismic surveys across young mountain belts where a) structures are particularly well exposed and b) reflection patterns can be traced to considerable depth. The Alpine system is perhaps the best example of such a system. Preliminary three dimensional seismic modeling by the Swiss of known Alpine structures, and their extrapolations to depth have proven to be an effective interpretational tool in providing a quantitative test of hypothesized structure in this active region. By analogy, considerable light may be shed upon the crustal architecture of older mountain belts where deep structural interpretations have been more cryptic. Thus this work may make the Alps a prototype for intercontinental collisions and a laboratory for calibration of deep seismic reflection data elsewhere.