Studies of Global and Regional Seismicity

该项目涉及全球和区域地震活动性的研究，其核心是哈佛大学中心矩张量（CMT）项目的延续，该项目目前代表了22年来分析全球地震活动和维护地震震源机制综合权威目录的努力，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，以及任何结果更新的历史。该项目的第二个组成部分是对以前未检测到的地震的检查。最近使用一种新的检测算法发现了超过1,800个震级大于4.7的事件，其中相当一部分显然不是普通地震。这项工作将涉及对新事件的一级系统分析，以确定它们为什么没有被早期检测到（例如，是否所有的事件都缺乏高频辐射，因此是慢地震），以及对几组特定的检测结果的特定构造（或非构造）解释，包括（1）与火山爆发或崩塌有关的事件;（2）与阿拉斯加、南极洲和格陵兰冰川有关的事件;（3）北卡罗来纳州海岸外的事件，可能与海底滑塌有关。

This project involves studies of global and regional seismicity.Central to the project is a continuation of the HarvardCentroid-Moment-Tensor (CMT) Project, which now represents a22-year-long effort to analyze global earthquake activity and tomaintain a comprehensive and authoritative catalog of earthquakefocal mechanisms, the CMT Catalog. In addition to the systematicanalysis and of earthquakes and dissemination of earthquake information,the research also includes the development of a dynamic earthquakemoment-tensor database. The new catalog will be searchable on theweb, and will include auxiliary data, such as information about theseismograms and Earth model used in the analysis, the quality ofthe solution, and any history of updates to the results.A second component of the project is an examination of previouslyundetected earthquakes. More than 1,800 events with magnitudes greaterthan 4.7 have recently been found using a new detection algorithm, anda substantial subset of these are clearly not common earthquakes.The effort will involve a first-order, systematic analysisof the new events to determine why they eluded earlierdetection (e.g., whether all of the events lack high-frequencyradiation and are thus slow earthquakes) and the specific tectonic(or non-tectonic) explanations for several specific groups ofdetections, including (1) events associated with volcanic eruptionsor collapses; (2) events associated with glaciers in Alaska, Antarctica,and Greenland; and (3) events off the coast of North Carolina,possibly associated with submarine slumping.