Statistical Analyses of Great Earthquake Recurrence along the Cascadia Subduction Zone
Statistical Analyses of Great Earthquake Recurrence along the Cascadia Subduction Zone
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卡斯卡迪亚俯冲带大地震重现统计分析
DOI：
10.1785/0120120105
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发表时间：
2013
影响因子：
3
通讯作者：
M. Lawrence
中科院分区：
文献类型：
--
作者：
R. Kulkarni;I. Wong;J. Zachariasen;C. Goldfinger;M. Lawrence
Goldinger等人的研究成果。(2012)将卡斯卡迪亚俯冲带(CSZ)10000年前的深海浊积岩序列解释为被数百年的空隙隔开的板块边界大地震群的记录。我们对推断的地震记录进行了统计分析，以检验时间聚集模型，并计算随时间变化的复发间隔和概率。我们使用蒙特卡罗模拟来确定浊积岩的重现率是否服从符合泊松(无记忆)过程的指数分布。后者在0.05的统计学意义水平上被拒绝。我们对18个事件(不包括T2事件)的20个随机模拟星表进行了聚类分析，使用了来自浊流数据集的不确定年龄。结果表明，13个原木表现出统计上显著的聚类行为，分类概率为13=20或0.65。20个星表中的大多数(70%)包含两个或三个闭合星系团(包含相同或几乎相同数量的事件的序列)，并且当前星系团T1-T5在所有星表中一致出现。对13个表现为集群的猫类的分析表明，在当前集群中至少再发生一个事件的概率为0.82。考虑到目前的震群可能还没有关闭，未来50年和100年发生9级地震的可能性估计分别为0.17和0.25。我们还分析了结果对包括T2事件的敏感性，T2事件的全长破裂事件的地位尚不确定。T2的加入没有改变CSZ浊积岩数据中聚集行为的概率，但确实显著降低了当前聚集扩展到另一个事件的概率。在统计分析的基础上，计算出与时间无关和与时间相关的复发间隔。
Goldfinger et al. (2012) interpreted a 10,000 year old sequence of deep sea turbidites at the Cascadia subduction zone (CSZ) as a record of clusters of plate-boundary great earthquakes separated by gaps of many hundreds of years. We performed statistical analyses on this inferred earthquake record to test the temporal clustering model and to calculate time-dependent recurrence intervals and probabil- ities. We used a Monte Carlo simulation to determine if the turbidite recurrence in- tervals follow an exponential distribution consistent with a Poisson (memoryless) process. The latter was rejected at a statistical significance level of 0.05. We performed a cluster analysis on 20 randomly simulated catalogs of 18 events (event T2 excluded), using ages with uncertainties from the turbidite dataset. Results indicate that 13 cata- logs exhibit statistically significant clustering behavior, yielding a probability of clus- tering of 13=20 or 0.65. Most (70%) of the 20 catalogs contain two or three closed clusters (a sequence that contains the same or nearly the same number of events) and the current cluster T1-T5 appears consistently in all catalogs. Analysis of the 13 cat- alogs that manifest clustering indicates that the probability that at least one more event will occur in the current cluster is 0.82. Given that the current cluster may not be closed yet, the probabilities of an M 9 earthquake during the next 50 and 100 years were estimated to be 0.17 and 0.25, respectively. We also analyzed the sensitivity of results to including event T2, whose status as a full-length rupture event is in doubt. The inclusion of T2 did not change the probability of clustering behavior in the CSZ turbidite data, but did significantly reduce the probability that the current cluster would extend to one more event. Based on the statistical analysis, time-independent and time-dependent recurrence intervals were calculated.