2012年新源-和静<em> M</em><sub>S</sub>6.6地震前后地壳介质泊松比变化

引用本文

唐明帅, 王海涛, 魏芸芸, 李艳永, 葛粲, 王琼, 苏金波, 魏斌. 2012年新源-和静 M_S6.6地震前后地壳介质泊松比变化 [J]. 地震地质, 2019,41(5): 1123-1135.
TANG Ming-shuai, WANG Hai-tao, WEI Yun-yun, LI Yan-yong, GE Can, WANG Qiong, SU Jin-bo, WEI Bin. POISSON’S RATIO VARIATIONS OF CRUSTAL MEDIA BEFORE AND AFTER XINYUAN-HEJING M_S6.6 EARTHQUAKE IN 2012 [J]. SEISMOLOGY AND GEOLOGY, 2019,41(5): 1123-1135. 复制到剪切板

DOI:10.3969/j.issn.0253-4967.2019.05.004
Permissions

《地震地质》编辑部所有

2012年新源-和静 M_S6.6地震前后地壳介质泊松比变化

唐明帅¹, 王海涛^2,^*, 魏芸芸¹, 李艳永¹, 葛粲³, 王琼¹, 苏金波¹, 魏斌¹

1新疆维吾尔自治区地震局, 乌鲁木齐 830011

2中国地震台网中心, 北京 100045

3合肥工业大学, 合肥 230009

*通讯作者: 王海涛, 男, 研究员, 主要从事地震监测预报工作, E-mail: ht.wang@263.net。

〔作者简介〕唐明帅, 女, 1976年生, 2011年于中国地震局兰州地震研究所获固体地球物理学硕士学位, 高级工程师, 主要从事地震分析和地震学研究, 电话: 13565964156, E-mail: tmings65@sina.cn。

收稿日期: 2018-12-12

基金项目: 中国地震局地震科技星火计划项目(XH15046)、新疆维吾尔自治区自然科学基金(2016D01A061)、国家自然科学基金(41674063, 41474051)和新疆主动震源创新研究团队共同资助

摘要

文中利用远震P波接收函数, 联合接收函数H-κ叠加方法和时间窗滑动方法, 分析了2012年6月30日新疆新源-和静 M_S6.6地震震中距200km内11个固定地震台2009年1月—2012年12月(石场台为2006年1月—2012年12月)的地壳介质泊松比的变化特征, 分析了乌苏、石场和新源3个台站准重复接收函数的莫霍面Ps转换波到时( t_Ps)变化, 获得了以下认识: 1)在新源-和静 M_S6.6地震前2~3a的不同时段, 5个震中距<130km的台站的地壳介质泊松比相继出现了较为明显的持续下降过程, 与台站平均地壳泊松比相比, 下降幅度为0.003~0.014, 4个台站的下降幅度大于均值误差, 乌苏台(震中距最小, 为77km)的下降起始时间(2009年7月)最早; 6个震中距>150km的台站的地壳介质泊松比在均值上下波动, 没有出现明显的下降和持续低值现象; 2)出现泊松比低值异常的台站, 其接收函数 t_Ps在震前变小(Ps转换波在地壳内的走时变小), 在震后变大(Ps转换波在地壳内的走时变大); 3)综合分析泊松比下降的幅度、持续时间、后续变化过程及接收函数 t_Ps的变化, 推测这种异常变化的原因是地震孕育、发生过程中出现的地壳介质物性变化, 这一观测结果表明, 在高密度台网的支撑下, 接收函数方法可能成为探测强地震前地壳介质泊松比变化的一种新的技术途径。

关键词: 接收函数; 地壳介质泊松比变化; Ps转换波到时变化; 新源和静 M_S6.6地震前后

中图分类号:P315.2 文献标志码:A 文章编号:0253-4967(2019)05-1123-13

POISSON’S RATIO VARIATIONS OF CRUSTAL MEDIA BEFORE AND AFTER XINYUAN-HEJING M_S6.6 EARTHQUAKE IN 2012

TANG Ming-shuai¹, WANG Hai-tao², WEI Yun-yun¹, LI Yan-yong¹, GE Can³, WANG Qiong¹, SU Jin-bo¹, WEI Bin¹

1)Earthquake Agency of Xinjiang Uygur Autonomous Region. Urumqi 830011, China

2)China Earthquake Networks Center, Beijing 100045, China

3)Hefei University of Technology, Hefei 230009, China

Abstract

We analyzed the variation characteristics of Poisson’s ratio in crustal media from January 2009 to December 2012 at 11 fixed seismic stations(for station SCH, it is from January 2006 to December 2012)within an epicenter distance of 200km of the Xinyuan-Hejing M_S6.6 earthquake in Xinjiang on June 30, 2012 using the methods of P wave receiver functions, H- κ stacking of receiver functions, and time sliding window, and obtained the following conclusions:
(1)The crustal media’s Poisson ratio of five stations in an epicenter distance less than 130km showed a significant and long-lasting decline about 2~3 years before Xinyuan-Hejing M_S6.6 earthquake. Taking the crustal Poisson ratio mean value as reference, the decrease ranges between 0.003 and 0.014, the decrease in 4 stations are more than twice the mean error. The variations of the Poisson’s ratio in crust are characterized by “V” shape or “double V” shape. Earthquakes occur at the end of the formation of “V” shape. After the occurrence of earthquakes, the Poisson’s ratio continues to rise. The earliest initial fall appeared in July 2009 at WUS station which has the minimum epicentral distance(77km). The Poisson ratio of the crustal media of 6 stations with epicentral distance more than 150km fluctuated up and down around the mean value, and there is no significant decline or persistent low value.
(2)We analyzed the arrival-time variations of the quasi-repetitive receiver functions Ps converted wave( t_Ps)of the 3 stations WUS, SCH and XNY and found that the travel times of Ps converted waves became smaller in the crust before the earthquake and increased after the earthquake.
(3)Through the comprehensive analysis on the descending process, decline ranges, variations process, duration of Poisson’ ratio, the Ps converted waves arrival time variations, the original time of earthquake, and the number of stations, it is inferred that the cause for Poisson’s ratio anomalous variations is the change of physical properties of crustal media in the process of earthquake preparation and occurrence. Since the variation characteristics of crustal media may be related to the earthquake magnitude, the size of seismogenic area, the medium properties under stations, and the focal distance, whether the medium variation characteristics exist before and after Xinyuan-Hejing M_S6.6 earthquake will need more earthquake cases analyses.
(4)The H- κ stacking of receiver functions is used to calculate the velocity ratio. Because P-wave velocity is given, this method can only be applied when the Ps converted wave velocity of Moho surface of receiver functions changes before an earthquake. With the application of receiver functions to the analysis of more earthquake cases, we can gain more insights into the variation of crustal medium parameters during the seismogenic process. This observation indicates that the receiver function method may become a new approach to detect the Poisson’s ratio change of the crustal media before strong earthquake under the condition of high seismic network density.

Keyword: receiver function; Poisson ratio variation of the crustal media; the arrival-time variation of Ps converted wave; before and after Xinyuan-Hejing M_S6.6 earthquake

Show Figures

0 引言

在地震孕育过程中, 由于孕震区应力的增加, 地下介质将产生微破裂、扩容等变化, 从而引起介质的弹性参数变化, 地震波通过孕震区时, 波速也将发生相应变化, 这是利用波速比异常预测地震的重要依据(冯德益, 1981)。泊松比表示介质受力后横向与纵向的应变之比, 是反映地壳介质性质的参数, 波速比是介质泊松比的函数, 随泊松比的增大而增大(李善邦, 1981)。 20世纪50年代, 日本学者首先发现并研究了大地震前地震波速度的变化; 在60— 70年代中期, 前苏联、美国和日本的地震科学工作者纷纷注意到部分中强地震前后的波速异常变化(冯德益, 1981)。

自20世纪70年代, 中国学者陆续开展了对中强地震前后波速比异常特征的研究工作(冯德益等, 1974; 冯锐等, 1976; 黎明晓等, 2004; 张学民等, 2004; 刁桂苓等, 2005; 王林瑛等, 2008, 2011; 钱晓东等, 2013; 李艳娥等, 2014), 还有一些成功预报强震的震例, 1976年松潘-平武7.2级大地震之前出现的波速比异常是预报该地震的依据之一(徐果明等, 1982)。在新疆, 一些学者利用地震震相数据对新疆天山部分中强震前后的波速比异常进行了分析讨论(王桂岭等, 1979; 龙海英等, 2011a, b; 高朝军等, 2013; 张琳琳等, 2016), 这些震例为波速比异常研究提供了经验。

在上述研究地震前后波速比变化的工作中, 主要采用了日本地震学家和达清夫于1928年提出的和达法, 计算的波速比是各台数据总体的平均值。其计算结果的不确定因素主要由介质的横向不均匀性和计算方法的局限性所造成, 同时也受到时间服务、震相精度和震源深度等的影响(蔡静观, 2000)。远震P波接收函数是用远震P波波形的垂直分量对径向分量或切向分量作反褶积后得到的时间序列, 其主要由直达波、台站下方速度界面产生的Ps转换波及多次反射转换波震相组成, 在很大程度上消除了震源时间函数和传播路径的影响, 故可近似地认为其代表台站下方壳幔结构的响应。 Zhu等(2000)提出了利用径向接收函数中莫霍面的一次转换波Ps及多次反射转换波(PpPs、 PsPs+PpSs)叠加来确定台站下方的地壳介质波速比。与和达法相比, 该方法因地壳介质非均匀性造成的不确定性大大降低, 计算数据不受时间服务和震源深度的影响, 并且能获得整个地壳深度的介质波速比(泊松比), 弥补了和达法探测孕震区深部介质波速比变化的不足。因此, 本文联合接收函数 $H$ -κ 方法和时间窗滑动方法, 分析了距新源-和静M_S6.6地震震中200km内的11个台站在地震前后地壳介质泊松比是否存在变化及其具体变化模式, 同时利用准重复接收函数, 分析了3个台站不同时段的接收函数Ps转换波与直达P波的到时差变化。

1 接收函数 $H$ -κ 叠加搜索方法

对于一维水平单层地壳模型, 当给定地壳内介质中P波和S波的平均速度 $ν_{P} 和 ν_{S},$ 由公式(1)便可求得地壳的厚度 $H,$ 其中, $t_{Ps}$ 表示接收函数中莫霍面一次反射转换波Ps震相相对于初至P波的到时差, $p$ 为入射P波的射线参数。

$H = \frac{t_{Ps}}{\sqrt[]{1 / {v_{S}}^{2} - p^{2}} - \sqrt[]{1 / v_{P}^{2} - p^{2}}}$ (1)

然而, 利用式(1)计算莫霍面的深度需要解决莫霍面深度与波速比之间存在折中的问题。联合利用莫霍面多次反射转换波震相(PpPs、 PsPs+PpSs)与初至P波的到时差可以有效地获得台站下方的地壳厚度H和纵横波速比 $κ 。$ Zhu等(2000)提出利用莫霍面一次转换波Ps及多次反射转换波(PpPs、 PsPs+PpSs)叠加搜索能量最大值的方法确定地壳厚度(H)和纵横波速比 $κ,$ 由公式(2)进行计算:

$\begin{array}{l} t_{Ps} = H (\sqrt[]{1 / v_{S}^{2} - p^{2}} - \sqrt[]{1 / v_{P}^{2} - p^{2}}) \\ t_{PpPs} = H (\sqrt[]{1 / v_{S}^{2} - p^{2}} + \sqrt[]{1 / v_{P}^{2} - p^{2}}) \\ t_{PpSs + PsPs} = H (2 \sqrt[]{1 / {v_{S}}^{2} - p^{2}}) \\ s (H, κ) = \frac{1}{N} \times \overset{N}{\sum_{n = 1}} ω_{1} r (t_{1}) + ω_{2} r (t_{2}) - ω_{3} r (t_{3}) \end{array}$ (2)

其中, $r (t)$ 为径向接收函数的振幅, $t_{1} 、 t_{2} 和 t_{3}$ 表示Ps、 PpPs和PsPs+PpSs震相在预测的地壳厚度H和纵横波速比 $κ$ 条件下对应的到时。 $ω_{i} (i = 1, 2, 3)$ 为Ps、 PpPs和PsPs+PpSs震相的权重系数, 且有 $\sum ω_{i} = 1 。$ 利用网格搜索方法可以确定函数 $s (H, κ)$ 的最大值以及相应的地壳厚度H和地壳介质波速比κ , 通过公式 $σ = 0.5 (κ^{2} - 2) / (κ^{2} - 1)$ 可获得相应的地壳介质泊松比 $σ$ (李善邦, 1981)。应用 $H$ -κ 方法计算地壳的波速比时, 百分之几的初始速度模型误差几乎不影响 $ν_{P} / ν_{S}$ 值(Zhu et al., 2000; 危自根等, 2011)。

	Figure Option View Download New Window
	图 1 新疆地区地形图Fig. 1 Topographic map of Xinjiang area.

	Figure Option View Download New Window
	图 2 地震震中和地震台站分布红色三角形为泊松比有变化的台站Fig. 2 Distribution of earthquake epicenters and seismic stations.

2 研究区域和资料选取

2.1 新源-和静M_S6.6地震构造背景

2012年6月30日, 新疆新源、和静县交界处发生M_S6.6地震, 震中位于(43.429° N, 84.755° E), 震源深度21.8km(李志海等, 2014)。此次地震是1970年以来新疆天山中东段地区发生的最大地震, 余震丰富。 2011年11月1日在新疆尼勒克县发生M_S6.0地震, 震中(43.65° N, 82.38° E)位于新源-和静6.6级地震以西约194km(图 2), 震源深度28km, 震源断错性质为右旋走滑逆断(聂晓红等, 2018)。在印度板块与欧亚板块的碰撞挤压作用下, 准噶尔和塔里木盆地周边的山体沿山前断裂向盆地逆冲, 在天山南、北麓发育大型逆冲推覆构造(图 1)。同时, 强烈的挤压构造运动产生的不均匀侧向水平剪切作用使得天山、昆仑山和阿尔金山内部形成了大型走滑断裂, 其中天山的构造变形特点较为复杂, 不仅山前发育多个逆冲推覆构造, 山体内部还发育了大型逆冲走滑断裂(沈军等, 2003)。 2012年新源-和静M_S6.6地震的发震构造为喀什河断裂, 是天山内部的一条大型断裂, 其总体走向为290° ~310° , 断面N倾, 倾角50° ~80° 。该断裂控制了伊犁盆地北界, 北盘上升, 南盘下降, 属于走滑逆断性质(图 2)。

	Figure Option View Download New Window
	图 3 提取接收函数的地震震中分布红色圆形为地震震中, 蓝色三角形为新源台Fig. 3 Epicenter distribution of earthquakes for receiver function extraction.

2.2 资料选取及数据处理

为了认识新源-和静M_S6.6地震前后地壳介质泊松比变化的可能范围, 本文收集了11个固定数字地震台(震中距< 200km)2009年1月— 2012年12月(石场台2006年1月— 2012年12月)记录的震中距为30° ~90° 、震级M≥ 5.5的高质量远震波形数据, 用于计算接收函数。图 2是地震台站和2次地震的震中分布, 图 3 给出了计算研究区新源台接收函数的地震震中分布。对收集到的远震波形数据进行预处理, 应用时间域的迭代反褶积方法提取各台站的接收函数(Ligorra et al., 1999)。从时域迭代拟合率 ≥ 85% 的接收函数中筛选出方位相对集中、波形相关性好、间断面Ps转换波震相清晰且到时一致的接收函数用于泊松比的滑动计算。石河子台存在壳内间断面Ps震相, 且能量强于莫霍面Ps震相, 对应的壳内深度为16.4km(表1), 因此对于该台使用壳内间断面Ps震相用于泊松比滑动分析。通过整理和归纳研究区已有的地壳结构研究成果, 确定 $v_{P}$ 为6.1km/s(石河子台 $v_{P}$ 取5.6km/s), 为使用接收函数 $H$ -κ 叠加方法滑动计算台站下方的地壳介质泊松比提供P波速度值。在滑动分析过程中, 为了避免多个极值的影响, 本文给定的地壳厚度范围为平均地壳厚度± 0.5km。

表1 地震台站相关信息和泊松比变化信息 Table1 Information on seismic stations and Poisson’ s ratio variations

3 各台站地壳介质泊松比的变化特征

表1给出了所用11个地震台的相关信息。通过对各台站接收函数进行滑动 $H$ -κ 分析, 得到了各台站的地壳介质泊松比变化情况(图 4, 图 5)。纵坐标的取值范围不一致, 主要是由于不同地震台站下方地壳平均泊松比值不同(表1)。震中距< 130km的5个台站观测到了地壳介质的泊松比变化, 变化特征具有一致性(图 4)。

	Figure Option View Download New Window
	图 4 5个震中距< 130km的地震台站泊松比滑动变化图红色圆圈表示1个窗长对应的泊松比值, 对应的时间是该滑动窗长的中间值, 黑色横线表示泊松比均值, 绿色直线表示泊松比均值计算误差Fig. 4 The variations of Poisson’ s ratio of 5 seismic stations with epicentral distance less than 130km.

	Figure Option View Download New Window
	图 5 6个震中距> 150km地震台站泊松比滑动变化图(图注同图 4)Fig. 5 The variations of Poisson’ s ratio of 6 seismic stations with epicentral distance greater than 150km(The captions are the same as Fig. 4).

震中距< 130km的5个台站的地壳介质泊松比出现了下降现象, 下降过程较为明显且持续时间较长。乌苏台的地壳介质泊松比变化呈双“ V” 字形, 其余4个台站的地壳介质泊松比变化呈“ V” 字形, 地震发生在“ V” 字形的回升尾端, 地震发生后泊松比继续回升(独山子台除外)。 2011年11月尼勒克M_S6.0地震震中距新源台75km, 在该地震前后, 新源台的地壳泊松比也出现了类似的变化。 5个台站的泊松比整体变化形状与祁连5.3级、门源6.4级地震前通过主动源观测到的震相走时变化形状(呈“ V” 或双“ V” 字形)相似(张元生等, 2017), 但不同台站的泊松比下降幅度、低值持续时间和下降起始时间存在不同, 这些差异可能与台站的观测环境、地下介质的性质以及震源距不同有关。 6个震中距> 150km的台站的地壳介质泊松比在均值上下波动, 没有出现明显的下降或持续低值的过程(图 5), 但库尔勒台和硫磺沟台的接收函数莫霍面Ps震相到时明显随方位变化, 这可能是导致这2个台的泊松比滑动结果出现斜线趋势的原因。

4 分析与讨论

4.1 泊松比计算结果的合理性分析

我们从时域迭代拟合率≥ 85%的接收函数中筛选出方位相对集中、波形相关性好、间断面Ps转换波震相清晰且到时一致的接收函数用于泊松比滑动计算。各台站挑选的接收函数后方位角(BAZ)主要分布在40° ~180° (表1); 震中距主要集中在38° ~82° , 少数分布在84° ~89° 。影响泊松比计算精度的主要因素有接收函数波形的相似度、信噪比、方位差异、震中距范围和接收函数个数等。乌苏、石场和新源3个台站有充足的相关性好的接收函数样本, 表2给出了每个台站不同时间窗相同泊松比值对应的接收函数个数、反方位角和震中距分布范围, 分析认为在满足本文的接收函数挑选条件后, 这3个因素对计算结果的影响小于本文观测到的泊松比变化。表1给出了各台站所用接收函数的数量, 通过 $H$ -κ 叠加所有接收函数得到的各台站的平均波速比和计算误差, 考虑到图 4 中各台站泊松比出现明显低值, 所以表1中也给出各台站的平均泊松比和负向计算误差。 5个泊松比出现明显降低的台站, 其泊松比负向计算误差为0.003~0.004, 以平均值为参考, 泊松比下降幅度均大于负向计算误差(表1)。由于接收函数反映了台站下方及周围较小距离的三维空间的介质结构, 因此不能排除莫霍面小尺度起伏、介质各向异性和非均匀体散射等带来的影响, 而对本文给出的未做滑动平均处理的计算结果而言, 泊松比在下降或上升过程中出现个别突跳现象(图 4)可能是以上因素所致。 Audet(2010)分析了PKD台站接收函数功率谱密度(PSD)随时间的变化, 发现在2003年圣西米恩M6.5地震后, 该台接收函数功率谱密度下降了5dB(PKD台距震中65km), 相当于泊松比降低了0.02。本文得到的泊松比降低幅度为0.003~0.014。

表2 本文乌苏、石场和新源地震台泊松比相等滑动窗的接收函数信息和计算结果 Table2 Receiver functions data and the calculation results of the sliding windows with equal Poisson’ s ratios at seismic station WSU, SCH and XNY in this paper

台站	滑动窗	滑动起止时间	接收函数个数	反方位角 /(° )	震中距 /(° )	地壳厚度 /km	波速比	泊松比
乌苏台	2	2009-03-04— 2009-08-31	5	107.6~124.7	37.8~75.3	45.106	1.836	0.289
	17	2011-08-21— 2012-02-17	4(0)	114.7~128.0	48.3~71.3	45.002	1.836	0.289
	18	2011-10-20— 2012-04-17	5(4)	114.7~128.0	48.3~71.3	45.002	1.836	0.289
	3	2009-05-03— 2009-10-30	5	107.6~124.9	37.8~75.3	45.372	1.827	0.286
	9	2010-04-28— 2010-10-25	15(0)	104.7~127.2	38.4~80.2	45.968	1.827	0.286
	7	2009-12-29— 2010-06-27	13	101.3~127.3	36.4~84.0	45.764	1.825	0.286
	15	2011-04-23— 2011-10-20	3(0)	109.4~127.9	60.3~75.3	45.776	1.825	0.286
	8	2010-02-27— 2010-08-26	18	101.3~127.3	36.4~88.0	45.660	1.834	0.289
	10	2010-06-27— 2010-12-24	15(10)	104.7~127.2	36.4~80.2	45.660	1.834	0.289
	19	2011-12-19— 2012-06-16	7(0)	92.1~128.0	36.3~87.6	45.538	1.834	0.289
	22	2012-06-16— 2012-12-13	5	119.5~123.8	41.0~56.7	45.004	1.844	0.292
	23	2012-08-15— 2013-02-11	4(4)	119.5~123.8	41.0~56.7	45.004	1.844	0.292
石场台	3	2006-05-25— 2006-11-21	4	62.2~98.5	38.3~49.9	55.783	1.738	0.253
	4	2006-07-14— 2007-01-10	4(4)	62.2~98.5	38.3~49.9	55.783	1.738	0.253
	5	2006-09-02— 2007-03-01	4	62.2~98.5	38.3~53.6	55.800	1.743	0.255
	7	2006-12-11— 2007-06-09	3(1)	73.0~95.4	45.0~53.6	55.792	1.743	0.255
	16	2008-03-05— 2008-09-01	25(0)	43.8~99.9	33.4~61.5	55.776	1.743	0.255
	28	2009-10-26— 2010-04-24	3(0)	46.4~78.5	35.4~59.7	55.744	1.743	0.255
	9	2007-03-21— 2007-09-17	11	44.4~86.6	37.7~61.6	54.956	1.752	0.258
	10	2007-05-10— 2007-11-06	15(11)	44.4~95.9	37.7~61.6	54.956	1.752	0.258
	15	2008-01-15— 2008-07-13	16(0)	44.9~99.9	33.4~60.7	54.902	1.752	0.258
	31	2010-03-25— 2010-09-21	8(0)	40.8~75.5	40.8~63.9	54.850	1.752	0.258
	32	2010-05-14— 2010-11-10	9(0)	40.8~75.5	40.8~63.9	54.850	1.752	0.258
	13	2007-10-07— 2008-04-04	4	45.7~79.0	42.2~60.5	55.749	1.742	0.254
	14	2007-11-26— 2008-05-24	12(1)	44.9~99.9	33.4~60.7	55.782	1.742	0.254
	17	2008-04-24— 2008-10-21	23	43.8~92.1	33.4~61.5	55.096	1.746	0.256
	25	2009-05-29— 2009-11-25	4(0)	39.7~86.7	41.6~65.3	55.598	1.746	0.256
	33	2010-07-03— 2010-12-30	8(0)	40.8~75.5	40.8~63.9	55.741	1.746	0.256
	47	2012-06-02— 2012-11-29	8(0)	40.0~77.5	41.0~65.2	55.793	1.746	0.256
	23	2009-02-18— 2009-08-17	4	45.5~86.7	41.6~60.5	55.799	1.740	0.253
	34	2010-08-22— 2011-02-18	6(0)	44.5~85.9	40.8~62.1	55.772	1.740	0.253
	45	2012-02-23— 2012-08-21	13(0)	40.0~82.0	41.4~65.2	55.786	1.740	0.253
	26	2009-07-18— 2010-01-14	5	39.7~86.7	35.4~65.3	55.541	1.749	0.257
	29	2009-12-15— 2010-06-13	4(2)	46.4~78.5	35.4~59.7	54.991	1.749	0.257
	35	2010-10-11— 2011-04-09	26	73.6~85.9	41.5~45.5	55.716	1.728	0.248
	40	2011-06-18— 2011-12-15	23(0)	42.2~84.5	41.4~63.4	55.714	1.728	0.248
	37	2011-01-19— 2011-07-18	52	42.4~82.2	41.3~63.4	55.734	1.727	0.248
	38	2011-03-10— 2011-09-06	58(49)	42.2~84.5	41.3~63.4	55.734	1.727	0.248
	39	2011-04-29— 2011-10-26	32(18)	42.2~84.5	41.3~63.4	55.734	1.727	0.248
	43	2011-11-15— 2012-05-13	9(0)	72.3~82.0	41.1~43.0	55.748	1.727	0.248
	7	2009-11-30— 2010-03-30	6	76.9~116.6	38.6~84.7	53.380	1.802	0.278
新源台	8	2010-01-14— 2010-05-14	7(5)	76.9~116.6	38.6~88.7	53.390	1.802	0.278
	13	2010-08-27— 2010-12-25	2(0)	72.1~107.0	43.4~81.9	52.319	1.802	0.278
	14	2010-10-11— 2011-02-08	2(2)	72.1~107.0	43.4~81.9	52.319	1.802	0.278
	28	2012-07-02— 2012-10-30	3	70.1~75.9	42.8~44.0	52.310	1.788	0.272
	29	2012-08-16— 2012-12-14	3(3)	70.1~75.9	42.8~44.0	52.310	1.788	0.272

注表中“ 接收函数个数” 一列括号中的数字代表与上一滑动窗口重复的接收函数的个数。

4.2 接收函数Ps震相到时变化分析

接收函数中的莫霍面Ps震相为远震P波近垂直入射到台站下方的莫霍面所产生的一次反射转换波, 由于地壳厚度不变, 如果孕震区的波速发生变化, 则在强震发生前不同时间段的接收函数中莫霍面Ps震相到时(t_Ps)会出现变化。邵学钟等(2013)分析了应用远震Ps转换波随时间的变化来研究地壳介质动态变化的可行性。

不同射线参数远震体波的入射角度有所差别, 且台站附近介质的非均匀性对接收函数的振幅和到时均有影响(唐明帅等, 2013)。为了更好地对比不同时间段接收函数Ps震相的到时, 消除由于远震震源位置不同对结果产生的影响, 对同一地震台站, 我们选择了方位、震中距和射线参数十分相近的接收函数(准重复接收函数)用于分析t_Ps的变化。本文分析了乌苏、石场和新源3个台站的t_Ps变化。表3给出了选取的准重复接收函数的相关信息和具体的t_Ps值, 图 6为对应接收函数的剖面图。地震发生前, 同一台站距发震时间越近的接收函数, 其t_Ps到时变小, 暗示转换波Ps速度增大, 与利用主动源观测到祁连5.3级、门源6.4级地震前穿过孕震区的地震波走时变小的结论一致(张元生等, 2017); 地震发生后接收函数的t_Ps大于临震前接收函数的t_Ps(表3, 图 6), 暗示转换波Ps速度减小。应用接收函数H-κ 方法计算波速比时, 由于给定 $ν_{P},$ 当转换波Ps的速度增大, 则对应的波速比(泊松比)变小, 这与本文观测到的震前泊松比明显降低的结果一致。

表3 同一地震台站不同时间段接收函数莫霍面Ps转换波到时(t_Ps) Table3 The arrival time of Ps converted waves at the Moho obtained from receiver functions in a same seismic station at different time

	Figure Option View Download New Window
	图 6 同一地震台站不同时间段接收函数波形剖面图接收函数的编号和名称同表2, 红色为1号接收函数, 蓝色为2号接收函数Fig. 6 The receiver functions waveform profile of a same seismic station at different time.

5 结论

本文分析了新源-和静M_S6.6地震震中距200km内11个台站的P波接收函数滑动叠加和莫霍面Ps震相到时(t_Ps), 根据泊松比下降幅度、后续变化过程、接收函数的t_Ps变化、发震时间以及出现这些变化的台站数量和震中距, 认为在高台网密度情况下, 利用远震P波接收函数可以对地下介质泊松比变化进行动态监测。新源-和静M_S6.6地震发生前, 震中距< 130km的5个台站的地壳介质泊松比出现明显低值异常, 变化形态特征呈“ V” 或双“ V” 字型, 地震发生在“ V” 字形的回升尾端, 地震发生后, 泊松比继续回升。出现泊松比低值异常台站的接收函数的t_Ps在震前变小, 即Ps转换波在地壳内的走时变小; 震后t_Ps变大, 即Ps转换波在地壳内的走时变大。由于地壳介质的变化特征可能与地震大小、孕震区范围、台站下方的介质性质以及震源距等因素有关, 新源-和静M_S6.6地震前后出现的介质变化特征是否具有普遍性, 还需要更多的震例分析加以验证。由于给定了P波速度值, 故仅当地震前接收函数的莫霍面Ps转换波速度发生变化时, 才适合使用接收函数 $H$ -κ 方法计算波速比。随着应用接收函数对更多震例进行分析, 研究者对地震孕育过程中出现地壳介质参数变化的认识也会越来越清楚, 接收函数方法可能成为探测强地震前地壳介质泊松比变化的一种新的技术途径。

致谢在结果分析过程中, 与中国科学院地质与地球物理研究所陈棋福研究员、中国科学院青藏高原研究所裴顺平研究员进行了有益的讨论; 审稿专家对本文进行了细致的审阅并提出了富有建设性的修改意见, 提高了文章的质量。在此一并表示感谢!

The authors have declared that no competing interests exist.

参考文献

View Option

[1]	蔡静观. 2000. 波速比计算中的不确定因素和在地震预报中的应用[J]. 地震研究, 23(1): 51—56. CAI Jing-guan. 2000. The uncertain factors in the calculation of wave velocity ratio and its application in earthquake prediction[J]. Journal of Seismological Research, 23(1): 51—56(in Chinese). [本文引用:1]
[2]	刁桂苓, 周仕勇, 刘杰, 等. 2005. 岫岩地震序列的平均波速比前兆异常[J]. 华北地震科学, 23(4): 1—5. DIAO Gui-ling, ZHOU Shi-yong, LIU Jie, et al. 2005. Anomalies of mean v_P/ v_S ratio in the series of Xiuyan earthquake[J]. North China Earthquake Sciences, 23(4): 1—5(in Chinese). [本文引用:1]
[3]	冯德益, 谭爱娜, 王克芬. 1974. 近震地震波波速异常与地震预报[J]. 地球物理学报, 17(2): 84—97. FENG De-yi, TAN Ai-na, WANG Ke-fen. 1974. Velocity anomalies of seismic waves from near earthquakes and earthquake prediction[J]. Chinese Journal of Geophysics, 17(2): 84—97(in Chinese). [本文引用:1]
[4]	冯德益. 1981. 地震波速异常 [M]. 北京: 地震出版社. FENG De-yi. 1981. Velocity Anomalies of Seismic Waves [M]. Seismological Press, Beijing(in Chinese). [本文引用:1]
[5]	冯锐, 庞庆衍, 傅征祥, 等. 1976. 海城地震前后地震波速比的变化[J]. 地球物理学报, 19(4): 295—305. FENG Rui, PANG Qing-yan, FU Zhen-xiang, et al. 1976. Variations of V_P/ V_S before and after the Haicheng earthquake of 1975[J]. Chinese Journal of Geophysics, 19(4): 295—305(in Chinese). [本文引用:1]
[6]	高朝军, 宋春燕, 张琳琳, 等. 2013. 新疆新源、和静交界6. 6级地震前后波速比异常特征研究[J]. 内陆地震, 27(2): 121—126. GAO Chao-jun, SONG Chun-yan, ZHANG Lin-lin, et al . . 2013. Study on characteristics of velocity ratio anomalies before and after Xinyuan-Hejing earthquake with M_S6. 6[J]. Inland Earthquake, 27(2): 121—126(in Chinese). [本文引用:1]
[7]	黎明晓, 张晓东. 2004. 应用多台法测定华北地区地壳的平均波速比[J]. 地震, 24(1): 163—169. LI Ming-xiao, ZHANG Xiao-dong. 2004. Determining average seismic velocity ratios( V_P/ V_S)in the curst in North China region by multi-station method[J]. Earthquake, 24(1): 163—169(in Chinese). [本文引用:1]
[8]	李善邦. 1981. 中国地震 [M]. 北京: 地震出版社. LI Shan-bang. 1981. Earthquake Research in China [M]. Seismological Press, Beijing(in Chinese). [本文引用:1]
[9]	李艳娥, 王林瑛, 郑需要. 2014. 汶川地震前后波速比变化特征的再研究[J]. 地震学报, 36(3): 425—432. LI Yan-e, WANG Lin-ying, ZHENG Xu-yao. 2014. Restudy of the variation of v_P/ v_S before and after the Wenchuan earthquake[J]. Acta Seismologica Sinica, 36(3): 425—432(in Chinese). [本文引用:1]
[10]	李志海, 郑勇, 谢祖军, 等. 2014. 2012年6月30日新疆新源-和静 M_S6. 6地震发震构造初步研究[J]. 地球物理学报, 57(2): 449—458. LI Zhi-hai, ZHENG Yong, XIE Zu-jun, et al. 2014. A preliminary study of seismogenic structure for the Xinyuan-Hejing, Xinjiang M_S6. 6 earthquake of June 30, 2012[J]. Chinese Journal of Geophysics, 57(2): 449—458(in Chinese). [本文引用:1]
[11]	龙海英, 聂晓红, 唐兰兰. 2011 a. 新疆乌苏5. 1级地震前波速比异常震例研究[J]. 地震研究, 34(2): 126—130. LONG Hai-ying, NIE Xiao-hong, TANG Lan-lan. 2011 a. Study of the abnormity of wave-velocities ratio before M_S5. 1 Wusu earthquake in Xinjiang[J]. Journal of Seismological Research, 34(2): 126—130(in Chinese). [本文引用:1]
[12]	龙海英, 聂晓红, 唐兰兰. 2011 b. 新疆和静5. 6级地震前波速比异常震例分析[J]. 中国地震, 27(2): 147—154. LONG Hai-ying, NIE Xiao-hong, TANG Lan-lan. 2011 b. Case analysis of wave velocities ratio abnormity before Hejing M5. 6 earthquake in Xinjiang[J]. Earthquake Research in China, 27(2): 147—154(in Chinese). [本文引用:1]
[13]	钱晓东, 苏有锦. 2013. 2008年攀枝花6. 1级地震前后波速比变化研究[J]. 地震研究, 36(1): 15—23. QIAN Xiao-dong, SU You-jing. 2013. Variation research of wave velocity ratio before and after 2008 Panzhihua M_S6. 1 earthquake[J]. Journal of Seismological Research, 36(1): 15—23(in Chinese). [本文引用:1]
[14]	聂晓红, 曲延军. 2018. 2011年11月1日新疆维吾尔自治区尼勒克-巩留6. 0级地震 [G]∥蒋海昆, 杨马陵, 付红. 2018. 中国震例(2011—2012). 北京: 地震出版社: 155—187. NIE Xiao-hong, QU Yan-jun. 2018. The MS6. 0 Nilka-Gongliu, Xinjiang earthquake on November 1, 2011[G]∥JIANG Hai-kun, YANG Ma-ling, FU Hong. 2018. Earthquake Cases in China(2011—2012). Seismological Press, Beijing: 155—187(in Chinese). [本文引用:1]
[15]	邵学钟, 张家茹, 范会吉. 2013. 地震转换波探测 [M]. 北京: 地震出版社. SHAO Xue-zhong, ZHANG Jia-ru, FAN Hui-ji. 2013. Seismic Converted Wave Detection [M]. Seismological Press, Beijing(in Chinese). [本文引用:1]
[16]	沈军, 汪一鹏, 李莹甄, 等. 2003. 中国新疆天山博阿断裂晚第四纪右旋走滑运动特征[J]. 地震地质, 25(2): 183—194. SHEN Jun, WANG Yi-peng, LI Ying-zhen, et al. 2003. Late Quaternary right-lateral strike-slip faulting along the Bolokenu-Aqikekuduke Fault in Chinese Tian Shan[J]. Seismology and Geology, 25(2): 183—194(in Chinese). [本文引用:1]
[17]	唐明帅, 葛粲, 郑勇, 等. 2013. 短周期地震仪接收函数的可行性分析: 以新疆和田地震台阵为例[J]. 地球物理学报, 56(8): 2670—2680. TANG Ming-shuai, GE Can, ZHENG Yong, et al . . 2013. Feasibility analysis of short-period seismograph receiver function: An example of Hotan Seismic Array, Xinjiang[J]. Chinese Journal of Geophysics, 56(8): 2670—2680(in Chinese). [本文引用:1]
[18]	王桂岭, 吴秀莲, 敖雪明. 1979. 新疆一些中强震前后的波速比异常[J]. 西北地震学报, 1(2): 1—8. WANG Gui-ling, WU Xiu-lian, AO Xue-ming. 1979. Wave velocity ratio anomaly before and after some strong earthquakes in Xinjiang[J]. Northwestern Seismological Journal, 1(2): 1—8(in Chinese). [本文引用:1]
[19]	王林瑛, 郭永霞, 刘芳, 等. 2008. 文安地震前后首都圈分区波速比时变特征[J]. 地震学报, 30(3): 240—253. WANG Lin-ying, GUO Yong-xia, LIU Fang, et al. 2008. Temporal v_P/ v_S variation characteristics in different zones of China’s Capital area before and after 2006 Wen'an earthquake[J]. Acta Seismologica Sinica, 30(3): 240—253(in Chinese). [本文引用:1]
[20]	王林瑛, 李艳娥, 李芳, 等. 2011. 汶川地震前后地震波速比和视速度变化特征的研究[J]. 地震学报, 33(1): 1—14. WANG Lin-ying, Li Yan-e, LI Fang, et al. 2011. Temporal variation of v_P/ v_S, v_P and v_S before and after 2008 Wenchuan earthquake[J]. Acta Seismologica Sinica, 33(1): 1—14(in Chinese). [本文引用:1]
[21]	危自根, 陈凌, 杨小林. 2011. 辽东台隆、燕山带和兴蒙造山带台站下方地壳厚度和平均波速比( V_P/ V_S)的横向变化及其构造意义[J]. 地球物理学报, 54(11): 2799—2808. WEI Zhi-gen, CHEN Ling, YANG Xiao-lin. 2011. Transverse variations of crustal thickness and V_P/ V_S ratio under the stations in the Liaodong anteclise-Yanshan belt-Xingmeng orogenic belt and their tectonic implications[J]. Chinese Journal of Geophysics, 54(11): 2799—2808(in Chinese). [本文引用:1]
[22]	徐果明, 周惠兰. 1982. 地震学原理 [M]. 北京: 科学出版社. XU Guo-ming, ZHOU Hui-lan. 1982. Seismology Principle [M]. Science Press, Beijing(in Chinese). [本文引用:1]
[23]	张琳琳, 高朝军. 2016. 新疆天山地区的波速比异常分析[J]. 中国地震, 32(1): 118—126. ZHANG Lin-lin, GAO Chao-jun. 2016. Analysis of wave velocity ratio anomalies in Tianshan region, Xinjiang[J]. Earthquake Research in China, 32(1): 118—126(in Chinese). [本文引用:1]
[24]	张学民, 刁桂苓, 束沛镒. 2004. 华北地区地下介质波速比值( v_P/ v_S)研究[J]. 地震地质, 26(2): 305—317. ZHANG Xue-min, DIAO Gui-ling, SHU Pei-yi. 2004. Study on wave velocity ratio( v_P/ v_S)of underground media in North China[J]. Seismology and Geology, 26(2): 305—317(in Chinese). [本文引用:1]
[25]	张元生, 王宝善, 陈颙, 等. 2017. 2次强震发生前后主动源观测走时数据的变化[J]. 地球物理学报, 60(10): 3815—3822. ZHANG Yuan-sheng, WANG Bao-shan, CHEN Yong, et al. 2017. Travel-time variations before and after two major earthquakes derived from active-source seismic data[J]. Chinese Journal of Geophysics, 60(10): 3815—3822(in Chinese). [本文引用:2]
[26]	Audet P. 2010. Temporal variations in crustal scattering structure near Parkfield, California, using receiver functions[J]. Bulletin of the Seismological Society of America, 100(3): 1356—1362. [本文引用:1]
[27]	Ligorra J P, Ammon C J. 1999. Iteraive deconvolution and receiver-function estimation[J]. Bulletin of the Seismological Society of America, 89(5): 1395—1400. [本文引用:1]
[28]	Zhu L P, Kanamori H. 2000. Moho depth variation in Southern California from teleseismic receiver functions[J]. Journal of Geophysical Research, 105(B2): 2969—2980. [本文引用:]

2000

0.0

... 其计算结果的不确定因素主要由介质的横向不均匀性和计算方法的局限性所造成, 同时也受到时间服务、震相精度和震源深度等的影响(蔡静观, 2000) ...

2005

0.0

... 刁桂苓等, 2005 ...

1974

0.0

冯德益, 谭爱娜, 王克芬. 1974. 近震地震波波速异常与地震预报[J]. 地球物理学报, 17(2): 84—97.

FENG

De-yi

, TAN

Ai-na

, WANG

Ke-fen

. 1974. Velocity anomalies of seismic waves from near earthquakes and earthquake prediction[J]. Chinese Journal of Geophysics, 17(2): 84—97(in Chinese).

A Simple method for the determination of the locations of near earthquake hypo-centres using data from many seismic stations is given in addition to several methods of finding anomalies of seismic wave velocities. The chief attempt is to determine the variation of the mean wave velocity and velocity ratio in the hypocentral region before a large earthquake, and to draw maps of wave-front and travel-time variations. The anomalies of V p and V s and their ratio before and after the Sichi （西吉） earthquake （Dec. 3, 1970, M=5.7） are investigated in detail.Some preliminary results are obtained. Among them are: （1） The mean velocitiesVp0 Vs0 of P and S-waves and the ratio V p0 /V s0 obviously diminish during many months be-fore the forthcoming large earthquakes （M>5） in a zone around their hypocenters where the stress is concentrated; （2） On the-background of the reduced velocity and velocity ratio, the anomalous area shows a spindle-shape, approximately corresponds to the distribution of the directions of the initial motions of the P-waves of the main earthquake; （3） During the period of anomalous velocity before the large earthquakesthe mean ratio V p0 /V s0 within the Earth's crust and in the upper mantle of the wholeregion is also anomalous.The physical implications of the velocity anomalies before and after the large earthquakes and the changes within the earth's crust are discussed.Finally certain preliminary methods of using velocity anomalies to predict earthquakes are suggested.

利用较大地震前后的地震波特性变化探索地震预报的途径,是当前地震战线上的一个重要研究课题。地震波的运动学特性及动力学特性在较大地震前后均可能发生一定的变化,本文主要探索地震波运动学特性的变化——波速异常。

... 自20世纪70年代, 中国学者陆续开展了对中强地震前后波速比异常特征的研究工作(冯德益等, 1974 ...

0.0

1976

0.0

冯锐, 庞庆衍, 傅征祥, 等. 1976. 海城地震前后地震波速比的变化[J]. 地球物理学报, 19(4): 295—305.

FENG

Rui

, PANG

Qing-yan

, FU

Zhen-xiang

, et al. 1976. Variations of V_P/ V_S before and after the Haicheng earthquake of 1975[J]. Chinese Journal of Geophysics, 19(4): 295—305(in Chinese).

In this paper, the data of 147 earthquakes occurred before and after the Haicheng Earthquake of February 4, 1975, M = 7.3 have been analysed. The results obtained, indicate that before the main shock, anomalous variations of the velocity ratio V p /V s was quite obvious. Its values began to fall at first and then recovered. This negative anomaly of Vp/Vs seems to have been started at least 4 years ago. Maximum negative value of V p /V s can reach about 10% of its normal. Nearly 10 months after the conclusion of the anomaly, the main shock took place. Before the main event, the area occupied by the anomaly was quite large, while only in a small region around the earthquake source area, negative anomaly of the velocity ratio suddenly appeared immediately before the main shock, at a time when the value of Vp/Vs increased to the normal. Before the main event, the variation in the S-wave velo-city was not appreciable. However, P-wave velocity and its virtual velocity showed anomalous changes. About two months before an aftershock of magnitude 4.8, the value of Vp/Vs also appeared to be anomalous.Eight explosion records were also analysed, but no apparent velocity ratio anomaly was observed.As regards to the cause of the velocity ratio anomaly, we merely suppose that under the action of concentrated tectonic stress, rocks change in their elastic property and numerous microfractures are formed.

1. Institute of Geophysics, Academia Sinica; 2. Liaoning Provincial Seismological Bureau; 3. The Seismological Brigade of Lanzhou, National Seismological Bureau

本文分析了1975年2月4日海城7.3级地震前后147次地震的资料。结果表明,主震前地震波速比有明显的异常变化。纵横波速比V p /V s 表现为“下降—回升”的异常形态,负异常至少在主震前四年已出现,最大异常幅度为10％左右,负异常结束后十个月发生主震。主震前波速比异常区较大;而震源附近的小区域,仅在全区波速比回升后的临震前才出现了急剧的负异常。主震前横波速度变化不大,纵波和虚波速度出现异常变化。在一次4.8级强余震前两个月,波速比也出现了负异常。本文还分析了8次人工爆破,但未发现主震前波速比的异常变化。关于波速比异常的原因,初步认为是岩石在构造应力的集中作用下,弹性性质发生变化、内部出现大量微裂隙而造成的。

... 冯锐等, 1976 ...

2013

0.0

... 高朝军等, 2013 ...

2004

0.0

... 黎明晓等, 2004 ...

0.0

2014

0.0

... 李艳娥等, 2014), 还有一些成功预报强震的震例, 1976年松潘-平武7 ...

2014

0.0

李志海, 郑勇, 谢祖军, 等. 2014. 2012年6月30日新疆新源-和静 M_S6. 6地震发震构造初步研究[J]. 地球物理学报, 57(2): 449—458.

Zhi-hai

, ZHENG

Yong

, XIE

Zu-jun

, et al. 2014. A preliminary study of seismogenic structure for the Xinyuan-Hejing, Xinjiang M_S6. 6 earthquake of June 30, 2012[J]. Chinese Journal of Geophysics, 57(2): 449—458(in Chinese).

On June 30, 2012, an M(s)6. 6 earthquake occurred at the border between Xinyuan and Hejing counties, Xinjiang Uygur Autonomous Region. It is the largest earthquake between the M7. 1 Yushu, Qinghai Province event in 2010 and the M7. 0 Lushan, Sichuan Province event in 2013. Based on seismic phase data of the earthquake sequence recorded by the Xinjiang Digital Seismic Network, we relocated the M(s)6. 6 and its aftershocks by the absolute and relative location methods. The epicenter location of the mainshock is 43. 429 degrees N, 84. 755 degrees E, the focal depth is 21. 8 km, and the aftershocks are distributed in NW direction. In terms of the waveforms of the M6. 6 earthquake, we used the CAP method to make a grid search for the focal mechanism and the focal depth. The resulting focal mechanism solution includes 39 degrees, 46 degrees, 12 degrees for the strike, dip, and rake angles on one plane and 301 degrees, 81 degrees, 135 degrees on the other plane, respectively, and a focal depth of 21 km. So, the waveform inversion result is consistent with that by phase data. The strike and dip angles for the plane II of the focal mechanism solution are close to the Northern Edge fault of the Yili basin, and the relocated distribution of the aftershocks is also in agreement with the characteristics of the fault. Therefore, this fault should be the seismogenic structure of the Xinyuan-Hejing M(s)6. 6 earthquake, which is of high angle and dip-slip in nature.

[Li Zhi-Hai; Liu Jian-Ming; Shangguan Wen-Ming] Earthquake Adm Xinjiang Uygur Autonomous Region, Urumqi 830011, Peoples R China.;[Zheng Yong; Xie Zu-Jun; Shan Bin] Chinese Acad Sci, State Key Lab Geodesy & Earths Dynam, Inst Geodesy & Geophys, Wuhan 430077, Peoples R China.

2012年6月30日新疆维吾尔自治区新源—和静县交界发生 M S 6.6地震，该地震是2010年青海玉树7.1级地震和2013年4月20日四川芦山7.0级地震之间中国大陆发生的最大的地震.本文基于新疆数字地震台网记录的此次地震序列震相资料，分别用绝对和相对定位方法联合对其进行重新定位，重新定位后余震展布为NW向，主震位置为43.429°N，84.755°E，深度为21.8 km.基于新疆地震台网记录6.6级地震波形数据，本文用CAP方法反演了震源机制解和震源深度.结果显示： M S 6.6地震震源机制解：节面Ⅰ走向39°，倾角46°，滑动角12°，节面Ⅱ走向301°，倾角81°，滑动角135°；震源深度为21 km，与利用地震震相到时确定的主震震源深度基本一致.主震震源机制解的节面Ⅱ与伊犁盆地北缘断裂走向和倾角基本一致，综合精确定位余震展布和伊犁盆地北缘断裂性质分析认为，新源—和静 M S 6.6地震发震构造是伊犁盆地北缘断裂，震源深度为21 km左右，是一个高角的内陆倾滑地震.

... 8km(李志海等, 2014) ...

2011

0.0

2011

0.0

2013

0.0

... 钱晓东等, 2013 ...

0.0

2003

0.0

沈军, 汪一鹏, 李莹甄, 等. 2003. 中国新疆天山博阿断裂晚第四纪右旋走滑运动特征[J]. 地震地质, 25(2): 183—194.

SHEN

Jun

, WANG

Yi-peng

, LI

Ying-zhen

, et al. 2003. Late Quaternary right-lateral strike-slip faulting along the Bolokenu-Aqikekuduke Fault in Chinese Tian Shan[J]. Seismology and Geology, 25(2): 183—194(in Chinese).

The Bolokenu-Aqikekuduke Fault extends over 700km and obliquely cuts the North Tian Shan. The fault is quantitatively studied in this paper based on remote sensing data, field observation, and the analyses of the relationship between the morphology and the climate change. The fault is composed of two portions, the NW-striking western portion and the NWW-striking eastern portion. The western portion is right lateral strike-slip with a rate of 5mm/a, having a length of about 250km and extending northwestward into the Kazakhstan. Along the fault 3～4 rupture zones produced by Paleoearthquakes or historic earthquakes were found. It has the potential for generating strong earthquakes of Magnitude around 7.5. The NWW-striking fault of east portions is dominated by right lateral slip with a rate of 1～1.4mm/a. Relatively small rupture zones, no more than 10km long, were found along this fault. It has the potential for generating strong earthquake of magnitude around 7. The western section of the Bolokenu Aqikekuduke Fault is one of the major NW-striking right lateral strike-slip faults in central Asia, and it is the result of the regional clockwise shearing. It accommodates the different deformations between western and eastern Tianshan and transforms the tectonic deformation among different compressive area. The NWW-striking fault of eastern section was developed from the NWW-striking suture zone in Northern Tianshan. It is accompanied by the E-W-striking thrust system in the front of the mountains and makes up a typical strain partitioning style of the oblique compressive belt. The strain in the oblique compressive belt is partitioned into pediment thrust belt and intermontane strike-slip fault. They transform the deformation laterally along the mountains and directly toward the foreland basin.

1. Institute of Geology, China Seismological Bureau, Beijing 100029, China; 2. Seismological Bureau of Xinjiang Uygur Autonomous Region, Urumqi, 830011, China

利用遥感资料,通过野外实地考察并结合气候地貌事件的分析,对斜切北天山、长逾700km的博阿断裂(博罗科努-阿齐克库都克断裂)的右旋走滑运动进行了定量研究。该断裂分为西部NW向断裂和东部NWW向断裂。西部NW向断裂长近250km,向西北延伸进入哈萨克斯坦,右旋走滑速率可达5mm/a;由4～5个断裂段组成,其上发育3～4条古地震或历史地震形变带,显示具有发生7.5级地震的能力。东部NWW向断裂右旋走滑速率1～1.4mm/a;其上发现小规模古地震形变带,显示具备发生7级左右地震的能力。该断裂与山前的逆冲推覆构造之间构成典型的挤压区应变分配形式,即在斜向挤压作用下,变形分配为山前的逆冲推覆构造和山内的走滑断裂。

... 同时, 强烈的挤压构造运动产生的不均匀侧向水平剪切作用使得天山、昆仑山和阿尔金山内部形成了大型走滑断裂, 其中天山的构造变形特点较为复杂, 不仅山前发育多个逆冲推覆构造, 山体内部还发育了大型逆冲走滑断裂(沈军等, 2003) ...

2013

0.0

唐明帅, 葛粲, 郑勇, 等. 2013. 短周期地震仪接收函数的可行性分析: 以新疆和田地震台阵为例[J]. 地球物理学报, 56(8): 2670—2680.

TANG

Ming-shuai

, GE

Can

, ZHENG

Yong

, et al . . 2013. Feasibility analysis of short-period seismograph receiver function: An example of Hotan Seismic Array, Xinjiang[J]. Chinese Journal of Geophysics, 56(8): 2670—2680(in Chinese).

Using the teleseismic waveform data recorded by 9 sub-stations (including 1 set of broadband and 9 sets of short-period seismographs) of Hotan Seismic Array with an aperture about 3 km in 3 years, we studied and analysed the stability and reliability of short-period seismograph receiver function. By comparative analysis of the receiver function waveforms isolated from teleseismic waveform data recorded by short-period and broadband seismographs, the following results are obtained. (1) Receiver functions of short-period and broadband seismographs are very consistent and highly stable, they have good linear correlation (correlation coefficient 0. 9), but Ps seismic phases have small amplitude difference (about 20%), whenever the Gaussian coefficient value is 1. 5 or 2. 5. (2) The short-period seismograph receiver functions can replace broadband seismograph receiver functions, if a method using the seismic phase arrival time of receiver functions is adopted (such as grid-stacking-search method). (3) The result may cause wrong interpretation (e. g., the lower crust low-velocity layer) if only the waveform data of short-period seismograph receiver functions are used to invert for crustal S-wave velocity structure, because there exist large velocity deviations (about 0. 3 km/s) from lower crust to upper mantle, due to lack of low frequency information under 0. 155 Hz and the nonlinear amplitude response under 1 Hz of the short-period seismographs; so additional data sensitive to wave velocity value (such as surface wave dispersion) are needed for joint analysis.

Tang Ming-Shuai 1 ;Wang Hai-Tao 1 ;Zheng Yong 2 ;Ge Can 2,3 ;

利用新疆和田地震台阵3 km孔径范围内架设的9个子台(包括1套宽频带和9套短周期地震仪)记录的3年远震波形数据,对比研究和分析了短周期地震仪接收函数的稳定性和可靠性.通过比较和分析短周期和长周期地震仪获取的接收函数波形,结果发现:(1)短周期地震仪记录与宽频带地震仪记录得到的接收函数有很好的一致性,且具有较高的稳定性,无论 α 取值为1.5还是2.5,短周期地震仪接收函数与宽频带地震仪接收函数都具有较强的线性相关性(相关系数0.9),但Ps震相均存在小幅的振幅差(约20%);(2)采用接收函数震相到时信息的方法(如 H-κ 叠加搜索),短周期地震仪可以代替宽频带地震仪;(3)由于短周期地震仪缺乏0.155 Hz以下的低频信号和在1 Hz以下频段非线性的振幅响应,仅仅采用短周期地震仪接收函数波形反演台站下方S波速度结构,获得下地壳到上地幔顶部的速度偏差较大(约0.3 km/s),可能会造成错误解释(如下地壳低速层),因此需要和其它对波速值敏感的数据(如面波频散)进行联合分析.

... 不同射线参数远震体波的入射角度有所差别, 且台站附近介质的非均匀性对接收函数的振幅和到时均有影响(唐明帅等, 2013) ...

1979

0.0

... 在新疆, 一些学者利用地震震相数据对新疆天山部分中强震前后的波速比异常进行了分析讨论(王桂岭等, 1979 ...

2008

0.0

... 王林瑛等, 2008, 2011 ...

2011

0.0

... 王林瑛等, 2008, 2011 ...

2011

0.0

危自根, 陈凌, 杨小林. 2011. 辽东台隆、燕山带和兴蒙造山带台站下方地壳厚度和平均波速比( V_P/ V_S)的横向变化及其构造意义[J]. 地球物理学报, 54(11): 2799—2808.

WEI

Zhi-gen

, CHEN

Ling

, YANG

Xiao-lin

. 2011. Transverse variations of crustal thickness and V_P/ V_S ratio under the stations in the Liaodong anteclise-Yanshan belt-Xingmeng orogenic belt and their tectonic implications[J]. Chinese Journal of Geophysics, 54(11): 2799—2808(in Chinese).

We obtained the crustal thickness and average crustal V-P/V-S ratio along the profiles across the Liaodong anteclise, Yanshan belt and Xingm.eng orogenic belt using H-kappa stacking of receiver functions. The result shows that the average crustal thicknesses of these three tectonic units are 32, 33 and 35km, respectively, indicative of slight differences, and display distinct transverse variations in the crustal structure. The crust is thicker in the middle and thinner on each side in the Liaodong anteclise, whereas the thickness of the crust varies smoothly in the Yanshan belt. In the Xingmeng orogenic belt, the crust thickens sharply from southeast to northwest near the Solonker suture. The V-P/V-S ratio also fluctuates obviously in the study region. In particular, it varies laterally in the Yanshan belt and increases markedly nearby the boundary area between the Yanshan belt and the Xingmeng orogenic belt (near the north-south gravity lineament (NSGL)). However, the V-P/V-S ratio is relatively low and has no much change in the Xingmeng orogenic belt. The distinct crustal structures between the Yanshan belt and the Xingmeng orogenic belt are probably indicative of a more intense crustal modification in the Yanshan belt compared with the Xingmeng orogenic belt during Mesozoic-Cenozoic time. Significant changes in the crustal structure roughly coincide with the NSGL. This together with the concordant change in the deep lithospheric structure observed previously suggests that the NSGL may be a lithospheric-scale intra-continental tectonic boundary, the opposite sides of which may have evolved differently in the Phanerozoic. The thickening of the crust in the Xingmeng orogenic belt (near the Solonker suture) and the Liaodong anteclise appears to mirror the surface topography, and corresponds to relatively stable V-P/V-S ratios. This feature probably indicates relatively even Phanerozoic modifications of the crust in each region, resulting in minor lateral variations in the crustal structure and components at the present time.

[Wei Zi-Gen; Chen Ling] Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China.;[Wei Zi-Gen] Chinese Acad Sci, Grad Univ, Coll Earth Sci, Beijing 100049, Peoples R China.;[Yang Xiao-Lin] Shaanxi Earthquake Adm, Xian 710068, Peoples R China.

本文研究采用接收函数 H-κ 方法获得了辽东台隆、燕山带和兴蒙造山带台站下方的地壳厚度和平均波速比( V P / V S ).结果显示,研究区域三个构造区地壳平均厚度略有差别,分别为32、33 km和35 km,但横向变化特征各异.辽东台隆地壳中间厚两端薄,燕山带地壳厚度的变化相对平缓,而在兴蒙造山带内,以索伦缝合带为界地壳呈由东南向西北增厚趋势,并在缝合带附近变化迅速. V P / V S 比值在整个研究地区也表现出显著波动,特别是在燕山带波速比横向变化明显,在靠近兴蒙造山带的边界附近(大致对应于南北重力梯度带位置)明显增高;而在兴蒙造山带波速比则相对偏低,且横向变化较小.燕山带与兴蒙造山带地壳结构特征的差异表明,燕山带在中-新生代可能经历了更为强烈的后期改造.南北重力梯度带附近地壳结构的明显改变,并结合前人观测到的该处岩石圈深部结构的强烈横向变化,表明重力梯度带可能是一条岩石圈尺度的大型陆内构造边界带,其两侧地区可能经历了不同的显生宙岩石圈演化过程.兴蒙造山带(索伦缝合带附近)以及辽东台隆地壳厚度的变化与地形相对应,而其波速比值也相对稳定,这可能反映了两个区域各自受到的地壳改造横向差异性相对较小,结构和成分相对均匀.

... 危自根等, 2011) ...

0.0

2016

0.0

... 张琳琳等, 2016), 这些震例为波速比异常研究提供了经验 ...

2004

0.0

张学民, 刁桂苓, 束沛镒. 2004. 华北地区地下介质波速比值( v_P/ v_S)研究[J]. 地震地质, 26(2): 305—317.

ZHANG

Xue-min

, DIAO

Gui-ling

, SHU

Pei-yi

. 2004. Study on wave velocity ratio( v_P/ v_S)of underground media in North China[J]. Seismology and Geology, 26(2): 305—317(in Chinese).

In this paper,based on available S wave and P wave velocity structures beneath 16 seismic stations in North China,wave velocity ratios for every velocity layer beneath these stations are calculated.According to their seismicity and geographic locations,these stations are divided into three types and discussed separately.In macroseismic area,the V P / V S ratio is systematically higher than that in microseismic area,and the V P / V S ratio of some low-velocity layers in mid-lower crust is greater than 1.8. In seismically quiet area or at interior of stable block,however,the V P / V S ratio is relatively stable for the whole crust and upper mantle,in many layers of which the ratio is less than the normal V P / V S ratio(1.732).In transitional area,such as the marginal area of basins or stable blocks,the number of layers with high V P / V S value becomes less,but the average V P / V S values beneath the stations are generally still greater than 1.732.Moreover,beneath the stations in microseismic area,a layer of more than10km thickness is recognized,which has never been found in macroseismic area and may reflect the old continental nucleus or crystalline basement.Stations in the same tectonic unit of transitional area have the same S wave velocity structure,which might be the result of regional tectonic activities. In addition,the contour maps of V P / V S and S wave velocity at 10km,15km,20km and 25km depths were plotted and analyzed.The results showthat at 10km depth,taken the Taihang Mountains as a boundary,the V P / V S values in the western area are higher than those in the eastern area;but at greater depth,the V P / V S is higher in the eastern area,and especially much higher in Xingtai earthquake area at 25km depth.It can be seen from S wave velocity images,that the velocity differences between the eastern and western areas separated by the Taihang Mountains are very significant all the time,and there is no evidence of mixing-up even at 25km depth.This may indicate that the Taihang Mountains is an evident material variation belt,which extends to a great depth. The apparent differences of V P / V S in macroseismic and microseismic areas are of great significance to prediction of potential risk area of strong earthquake,while the differences in velocity structures and wave velocity ratio beneath various geological structures may provide some leads for the study of the history of local tectonic activities.

1. School of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China; 2. Earthquake Administration of Hebei Province, Shijiazhuang 050021, China; 3. Institute of Geology and Geophysics, Chinese Academy of Science, Beijing 100029, China

文中利用分别独立反演得到的华北地区16个台的S波和P波速度结构,计算了各台站下方分层速度结构各层的波速比值,发现在强震区的波速比总体上高于弱震区,且地壳中的一些低速层位会出现>1.8的波速比值,而在弱震区或稳定块体内部,各层波速比一般都低于正常波速比1.732,平均值甚至 1.732。在此基础上,最后我们对位于不同地质构造体的台站下方的介质性质进行了讨论。

... 张学民等, 2004 ...

2017

0.0

... 字形)相似(张元生等, 2017), 但不同台站的泊松比下降幅度、低值持续时间和下降起始时间存在不同, 这些差异可能与台站的观测环境、地下介质的性质以及震源距不同有关 ...

... 4级地震前穿过孕震区的地震波走时变小的结论一致(张元生等, 2017) ...

2010

0.0

... Audet(2010)分析了PKD台站接收函数功率谱密度(PSD)随时间的变化, 发现在2003年圣西米恩M6 ...

1999

0.0

... 对收集到的远震波形数据进行预处理, 应用时间域的迭代反褶积方法提取各台站的接收函数(Ligorra et al ...

2000