| 传染型余震序列模型震后早期参数特征及其地震学意义 |
| |
| 引用本文： | 蒋海昆,郑建常,吴琼,曲延军,李永莉.传染型余震序列模型震后早期参数特征及其地震学意义[J].地球物理学报,2007,50(6):1778-1786. |
| |
| 作者姓名： | 蒋海昆 郑建常 吴琼 曲延军 李永莉 |
| |
| 作者单位： | 1.中国地震台网中心，北京 100045;2.山东省地震局，济南 250014;3.新疆维吾尔自治区地震局，乌鲁木齐 830011;4.云南省地震局，昆明 650041 |
| |
| 基金项目： | 国家“十一.五”科技支撑计划项目子专题(2006BAC01B03-02-02)资助 |
| |
| 摘 要： | 研究中国大陆地区中强地震序列震后早期阶段（震后15天）ETAS模型参数的平均统计特征，据此讨论不同统计条件下的序列衰减及余震激发问题.宏观而言，模型参数b、p、α数值分布较为离散，不同统计条件下模型参数平均值的差异显著性不十分突出.详细对比不同统计条件下模型参数平均值的微小差异，b值随主震震级增大而增大，但b值随不同区域、不同主震断层类型或不同序列类型的变化不明显.p、α具有一定的区域特征，西南、西北p值略低于新疆及华北，表明西南、西北序列衰减相对较慢而新疆、华北序列衰减相对较快，华北α较低而西北α相对最高，意味着尽管华北序列衰减相对较快，但其激发高阶余震的能力却相对强，西北尽管序列衰减较慢，但序列结构单一，激发高阶余震的能力弱.p与主震断层类型关系不明显，即主震破裂性质不是决定序列衰减快慢的主要因素；α与主震断层类型有一定关系，走滑-近走滑型破裂所导致序列的α值最小、斜滑型次之、倾滑-近倾滑型最大，表明走滑-近走滑型序列激发高阶余震的能力最强、逆冲型最弱、斜滑型居中.p、α随主震震级增大而减小，意味着主震震级越高则序列衰减越慢、激发高阶余震的能力越强.不同类型序列p、α有一定差异，主余型序列p最小、孤立型p最大，表明相对而言主余型序列衰减最慢、孤立型序列衰减最快、多震型序列衰减速率居中.孤立型序列与主余型序列α大体一致、大于多震型序列的α值，即多震型序列激发高阶余震的能力相对最强，孤立型及主余型序列则相对较弱.
|
| 关 键 词： | ETAS模型 中国大陆 地震序列 序列衰减 余震激发 |
| 文章编号： | 0001-5733（2007）06-1778-09 |
| 收稿时间： | 2006-9-18 |
| 修稿时间： | 2006-09-18 |
Earlier statistical features of ETAS model parameters and their seismological meanings |
| |
| JIANG Hai-Kun,ZHENG Jian-Chang,WU Qiong,QU Yan-Jun,LI Yong-Li.Earlier statistical features of ETAS model parameters and their seismological meanings[J].Chinese Journal of Geophysics,2007,50(6):1778-1786. |
| |
| Authors: | JIANG Hai-Kun ZHENG Jian-Chang WU Qiong QU Yan-Jun LI Yong-Li |
| |
| Institution: | 1.China Earthquake Networks Center, Beijing 100045, China;2.Earthquake Administration of Shandong Province, Jinan 250014, China;3.Earthquake Administration of Xinjiang Autonomous Region, rümqi 830011, China;4.Earthquake Administration of Yunnan Province, Kunming 650041, China |
| |
| Abstract: | The average statistical features of ETAS (Epidemic Type Aftershock Sequence) model parameters during the earlier stage (15 days) after the moderate or large earthquakes in Chinese mainland have been studied and the decay and generation of aftershocks under the different conditions also have been discussed. Macroscopically, the numerical distribution of primary parameters of ETAS model, b, p, and α, are dispersed and the differences of average value of parameters under the different conditions are not very prominent. In detail, b- value increases with the magnitude of the mainshock, but the differences of b-value are not obvious for different regions, for different modes of mainshock fracture, as well as for different sequence types. p-value and α-value show some regional features to some extent. Average p-values in southwest and northwest region of China are a little larger than that in Xinjiang and in North China, this means that the decay of aftershock activity is a little slower in southwest region and in northwest region than that in Xinjiang and in North China. Average α-value is small in northwest region, and is large in North China. This indicates that the earthquake in North China has a high ability to generate high-order aftershocks, although the aftershock decay in North China is relatively quick. And for northwest region of China, despite the slow aftershock decay, but due to the simplicity of aftershock sequence, the ability of high order aftershock generation is weak. The relation between p-value and the fracture mode of the mainshock is not evident, that is, the mainshock fracture mode is not the key factor controlling the aftershock decay rate. α-value is related to the mainshock fracture mode to some extent. Averagely, α-value is small for strike-slip, middle for oblique slip and large for dip slip. This means that strike-slipping has the ighest ability to generate aftershocks, it is weakest for dip slip and middle for oblique slip. p-value and α-value decrease with the increment of the mainshock magnitude, this means that the larger the mainshock, the slower the sequence decay and the higher the ability to generate offspring. There are some differences in p-values and α-values for different sequence types. p-value is smaller for mainshock-aftershock type (MAT) and larger for isolated earthquake type (IET), this indicates that decay rate of aftershock is slow for MAT, is quick for IET and is in the middle for multiple mainshock type (MMT). α-values of IET and MAT are about the same, both two are larger than that of MMT. This means that MMT has a higher ability to generate high-order aftershocks than that of IET and MAT. |
| |
| Keywords: | ETAS model Chinese mainland Earthquake sequence Aftershock decay Generation of aftershocks |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《地球物理学报》浏览原始摘要信息 |
| 点击此处可从《地球物理学报》下载免费的PDF全文 |
|
