Studies of Global and Regional Seismicity

该项目涉及对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，该项目目前代表了长达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。除了系统地分析地震和传播地震信息外，这项研究还包括建立一个动态地震矩-张量数据库。新的目录将可以在网络上搜索，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。该项目的第二个组成部分是检查以前未检测到的地震。每年，使用基于对地球长周期波场的系统监测的新检测算法检测到100多个震级大于4.7的地震，这些地震没有出现在标准地震目录中。这些新检测到的事件中最大的一组包括发生在沿着地球山脊转换断层系统的事件，并将调查这些事件的性质，以解释它们先前未被检测到的原因。第二类要调查的事件与重力滑动有关，包括阿拉斯加和其他地形起伏大的地区的滑坡事件、格陵兰岛海岸沿着的冰川地震，以及南北美洲大陆斜坡上可能发生的若干事件。

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.