Studies of Global and Regional Seismicity

这个项目涉及全球和区域地震活动的研究。该项目的核心是全球质心-矩-张量（CMT）项目的延续，该项目现在代表了一项长达25年的努力，旨在分析全球地震活动，并维护一个全面和权威的地震震源机制目录，即全球CMT目录。除了系统的地震分析和地震信息的传播外，研究还包括动态地震矩张量数据库的开发。新的目录将可在网上搜索，并将包括辅助数据，如分析中使用的地震图和地球模型的信息，解决方案的质量，以及结果更新的任何历史记录。该项目的第二个组成部分是对以前未探测到的地震进行检查。每年，使用一种基于地球长周期波场系统监测的新检测算法，检测到100多次震级大于4.7级的地震，这些地震没有出现在标准地震目录中。这些新发现的事件中最大的一组包括沿地球的山脊变换断层系统发生的事件，这些事件的性质将被调查，以解释它们早先未被发现的原因。要研究的第二类事件与重力滑动有关，包括阿拉斯加和其他地形起伏较大地区的山体滑坡事件、格陵兰海岸沿岸的冰川地震，以及北美和南美大陆斜坡上可能发生的一些事件。

This project involves studies of global and regional seismicity. Central to the project is a continuation of the Global Centroid-Moment-Tensor (CMT) Project, which now represents a 25-year-long effort to analyze global earthquake activity and to maintain a comprehensive and authoritative catalog of earthquake focal mechanisms, the Global CMT Catalog. In addition to the systematic analysis of earthquakes and dissemination of earthquake information, the research also includes the development of a dynamic earthquake moment-tensor database. The new catalog will be searchable on the web, and will include auxiliary data, such as information about the seismograms and Earth model used in the analysis, the quality of the solution, and any history of updates to the results.A second component of the project is an examination of previously undetected earthquakes. Each year, more than 100 earthquakes with magnitudes greater than 4.7 that are not present in standard earthquake catalogs are detected using a new detection algorithm based on systematic monitoring of the Earth's long-period wavefield.The largest group of these newly detected events includes events occurring along the Earth's ridge-transform fault system, and the nature of these events will be investigated to explain their earlier non-detection. A second class of events to be investigated is associated with gravitational sliding and includes landsliding events in Alaska and other regions of high topographic relief, glacial earthquakes along the coast of Greenland, and potentially several events on the continental slope of North and South America.