Temporal and Spatial Variations of Local Magnitudes in Alaska and Aleutians and Comparison with Body-Wave and Moment Magnitudes
Temporal and Spatial Variations of Local Magnitudes in Alaska and Aleutians and Comparison with Body-Wave and Moment Magnitudes
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阿拉斯加和阿留申群岛局部震级的时空变化及其与体波和力矩震级的比较
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
R. Hansen
中科院分区：
文献类型：
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作者：
N. Ruppert;R. Hansen
摘要对阿拉斯加地震信息中心地震目录中的L震级的时空变异性进行了评估。从20世纪70年代初开始，目录中就有阿拉斯加大陆地区记录的震中。在20世纪90年代中期之前，阿留申地区没有全面的L先生的统计数据。我们确定了L震级与体波震级mb之间具有相似震级残差趋势的四个时间间隔：1971年-1976年、1977年-、1990年-1999.5和1999.5-2008年。后三个区间也被确定为M L与矩震级Mw的残差趋势。这些时间间隔对应于具有不同数据处理程序的时段。我们发现，最新的时间间隔在阿拉斯加大陆的M-L和M-W值之间具有最好的对应关系，特别是在浅层(目录中出现了M-L对Mb和M-L对M-W)。对于1990年前的数据，阿拉斯加湾地震的差异最大。最近一段时间(1999.5-2008年)，位于阿留申弧洋段和海沟100000公里范围内的地震，在L和Mb或Mw之间观测到的残差最大。我们计算了一组阿拉斯加大陆和阿留申地区的震级校正，需要应用这些校正来使星表中的震级值在时间和空间上均一化。
Abstract We evaluated temporal and spatial variability of local magnitudes ( M L ) in the earthquake catalog of Alaska Earthquake Information Center. Regionally recorded hypocenters in mainland Alaska are available in the catalog beginning in the early 1970s. No comprehensive Aleutian-wide M L statistics exist prior to the mid-1990s. We identify four time intervals with similar magnitude residual trends between M L versus body-wave magnitude m b : 1971–1976, 1977–1989, 1990–1999.5, and 1999.5–2008. The three latter intervals are also identified in M L versus moment magnitude M w residual trends. These time intervals correspond to the periods with different data processing procedures. We find that the latest time interval has the best correspondence between M L and M w values in mainland Alaska, especially for shallow (depth M L versus m b and M L versus M w are present in the catalog. For the pre-1990 data, the largest discrepancies are observed for the Gulf of Alaska earthquakes. For the latest time period 1999.5–2008, the largest residuals between M L and m b or M w are observed for the earthquakes located within the oceanic segment of the Aleutian arc and within 100 km of the trench. We calculated a set of magnitude corrections for mainland Alaska and the Aleutians that need to be applied to homogenize magnitude values in the catalog in time and space.