Long-period source characteristics of the great 1964 Alaska earthquake

1964年的阿拉斯加地震是有记录以来第二大地震。目前对这次地震的长周期震源特征，包括地震规模和断层几何形状以及力矩释放的时间和分布的测试可以追溯到20世纪70年代。所有这些估计都是在现代地震图合成方法和矩张量测定方法发展之前作出的。2004年12月26日苏门答腊-安达曼地震（MW 9.2）已经把注意力重新集中到我们对1964年阿拉斯加地震的了解上，因为阿拉斯加地震是最自然的比较对象。拟议中的研究将利用现有的手工数字化，1964年主震的高质量面波地震图，用于地震矩张量、质心位置和深度以及质心时间的反演;地球横向速度不均匀性的影响将在反演中得到解释。由于1964年地震的规模非常大，而且现有数据与较晚到达的表面波轨道相对应，因此将进行几次实验以验证所获得的结果。从这项研究中获得的结果也将直接用于其他大地震的比较研究，包括2004年苏门答腊-安达曼群岛地震。此外，将1964年地震中可用的手工数字化数据存档的计划预计将使对地震动力学和地球结构感兴趣的研究人员受益。这项研究将支持早期职业科学家。在项目结束时，所使用的数据将永久存档，供其他研究人员将来使用。

The 1964 Alaska earthquake is the second-largest earthquake ever recorded instrumentally. Currentestimates of the long-period source characteristics of this earthquake, including the earthquake sizeand faulting geometry and the timing and distribution of moment release, date from the 1970s. Allof these estimates were made before the development of modern methods of seismogram synthesisand moment-tensor determination. The occurrence of the 26 December, 2004 Sumatra-AndamanIslands earthquake (MW 9.2) has returned attention to the state of our knowledge about the1964 Alaska earthquake, as the Alaska earthquake presents the most natural target for comparison.The proposed research will make use of existing hand-digitized, high-quality surface-waveseismograms from the 1964 mainshock in an inversion for the earthquake moment tensor, centroidlocation and depth, and centroid time; effects of Earth's lateral velocity heterogeneity will be accountedfor in the inversion. Owing to the very large size of the 1964 earthquake, and to the fact that the available data correspond to late-arriving surface-wave orbits, several experiments will be carried out to validate the results obtained. Results obtained from this study will also be of direct use for comparative studiesof other large earthquakes, including the 2004 Sumatra-Andaman Islands earthquake. In addition,the proposed effort to archive the available, hand-digitized data from the 1964 earthquake isanticipated to benefit researchers interested in both earthquake dynamics and Earth structure.The research will support an early-career scientist. At the conclusion of the project, the data used will be permanently archived to make them available for future use by other researchers.