利用聚类分析方法研究新疆呼图壁大容量气枪震源重复性

为研究造成新疆呼图壁大容量气枪震源重复性波动的原因,利用2015—2016年新疆呼图壁气枪震源激发池岸边的一台地震仪记录的3 214次激发信号,采用聚类分析中层次聚类方法和波形信号互相关技术,以相关系数大于0.95、对应相似度距离为0.05为标准对气枪震源信号进行聚类分析,将信号分成了2类。对可能造成气枪信号重复性波动的几种原因进行讨论,结果表明这种信号的重复性波动是气枪激发时压力不同造成的,建议通过控制激发压力的方法来解决这一问题。     

利用气枪震源信号研究2016年云龙M_S 5.0地震前后波速变化特征

以2016年5月18日云南云龙MS5.0地震为例,选取距震中较近的3个台站和较远的5个台站记录的2016年1—9月的气枪震源信号,使用互相关检测技术得到地震前后这8个台站各自稳定震相走时变化特征。结果表明:云龙地震前,各台均存在不同程度的走时异常变化。离震中较近的3台站中,震中西侧和东侧台站走时变化有一定差别,但都在地震前的3、4月变化较大;而离地震较远的5个台站则变化趋势特征一致,幅度略有差别;离地震较近台站走时变化幅度明显大于离地震较远台站;地震前小于0.7 m的水位变化并未对各台走时变化产生实质性影响。同时对比了云龙台FSQ水管倾斜的形变观测数据,监测到同一时段地下应力发生变化。     

新疆2次中强地震前气枪震源反射波震相走时异常变化初步研究

以新疆2次5级左右地震为震例样本,选取震中附近石河子台、石场台和乌苏台记录的2013年8月以来的气枪震源信号数据,依据反射波震相,采用互相关检测技术等,研究2次5级左右地震前走时变化特征,得到如下研究结果:1根据单双层"3400走时表"速度模型,参考理论Pm P走时选取震相窗是可靠的;22次5级左右地震前3个台站记录的Pm P走时变化均出现4个月和2个月左右不同程度的低值异常过程,相对走时变化幅度约为0.1%~0.26%,距震中较近的石河子台、石场台的异常特征显著于较远的乌苏台;32次5级左右地震前走时异常变化时间和幅度均存在差异,这可能与震级和震中位置有关。     

新疆呼图壁人工水体大容量气枪信号发射台性能研究

介绍了新疆呼图壁人工水体大容量气枪震源地震信号发射台的选址、建设过程及震源信号特征。从地质构造、历史地震的角度分析了地震信号发射台选址的合理性、必要性以及气枪激发池设计的合理性。利用激发池岸边的低灵敏地震仪记录到的气枪信号,阐述了气枪震源的高度重复性和人工水体气枪震源信号的稳定性,并对信号进行时频分析后得出,气枪信号的优势频率为2~6Hz。最后通过叠加的方法提高信噪比,得到呼图壁气枪震源信号的传播距离约为380km。     

新疆阿克陶、呼图壁两次6级地震前兆监测台网效能评估与研究

正2016年11月25日新疆克孜勒苏州阿克陶县发生6.7级地震;2016年12月8日新疆昌吉回族自治州呼图壁县发生6.2级地震。13天内,新疆连续发生两次6级地震。中国地震局监测预报司监测二处迅速响应,组织各学科有关专家对两次6级地震进行了震后梳理与总结。根据对两次地震震中500km范围内地震前兆固定观测台网的统计,阿克陶区域的监测台项数共计24个,台站数12个,分别占全疆台项、台站数的16.2%和21.4%;呼图壁区域的     

2017年3月27日漾濞5.1级地震前后气枪震源观测走时数据的变化

以2017年3月27日漾濞5.1级地震为例,根据区域特性和信噪比要求,选取数据较为完整的6个台站记录的2017年1月1日～6月6日期间的宾川地震信号发射台气枪震源波形资料,采用互相关检测技术提取6个台站各自稳定震相的走时数据,并对漾濞5.1级地震前后走时数据的变化情况进行分析。结果表明,漾濞5.1级地震前后6个台站各自稳定震相存在较为明显的走时变化,且短期内走时变化具有较好的同步性,相关台站异常幅度大小和异常出现时间存在细小差异。地震发生前,6个台站走时低值异常过程明显,以YUL台最为显著。地震发生前后走时变化形态特征为双“V”型,漾濞5.1级地震发生在第1个“V”型末端。地震发生后,不同方位相关台站受地震的影响程度不同,走时波动大小存在差异。     

浅析近2年新疆中强以上地震有序迁移及后续平静的动力学背景

正2017年12月7日新疆叶城5.2级地震至今,半年多新疆地区无5级以上地震;6级地震平静近1年;距离2014年2月12日新疆于田7.3级地震4年多。作为中国大陆强震主体区域的新疆地区地震平静备受关注。分析显示,2016年11月25日新疆阿克陶6.7级和2016年12月8日新疆呼图壁6.2级地震,2017年8月9日新疆精河6.6级等地震与2015年以来兴都库什地区一系列强震的发生存在     

浅析近两年新疆中强以上地震有序迁移的动力学背景

正2014年新疆于田7.3级地震至今,我国大陆7级以上地震已平静近4年,7级地震平静现象突出。作为中国大陆强震的主体发生区域新疆地区的地震发生备受关注,2016年底新疆地区13天连发2次6级地震,2016年11月25日新疆阿克陶6.7级和2016年12月8日新疆呼图壁6.2级地震,分析认为这2次新疆地震与2015年以来兴都库什地区一系列强震存在一定的联系。     

2016年新疆呼图壁6.2级地震前b值异常特征研究

利用2009年以来中国地震台网中心地震编目资料,以2016年新疆呼图壁6.2级地震作为研究对象,采用最大似然法进行b值空间扫描计算,获取震前震中及其邻区地震b值的空间图像。研究结果显示,2016年呼图壁6.2级地震发生在震前显著低b值区域,该异常特征可能反映了地震孕育的应力积累过程,印证了b值的物理意义。     

气枪震源地震波走时变化影响因素分析及地震相关的走时变化

云南省地震局在程海断裂以西10 km的大银甸水库处建成了气枪震源发射台, 在水库丰水期内进行连续激发观测。 2014年8月21日、 24日气枪震源附近分别发生M_S4.2、 M_L4.1和M_L4.0地震。 本文利用宾川气枪震源附近的钟英台、 黄坪台等10个台站2014年9月8日至2015年2月28日观测数据, 使用波形互相关方法提取这些台站气枪信号的走时变化, 使用射线追踪的方式正演研究了气压、 水库水位、 潮汐应力等因素对波速变化的影响。 排除上述影响后, 认为3次4级左右地震可能是2014年9月台站气枪信号走时增大0.04~0.05 s的原因。     

Damage Investigation of the Hutubi MS6.2 Earthquake on December 8, 2016

The Hutubi M_S6.2 earthquake occurred on December 8, 2016, in Hutubi County, Xinjiang Uygur Autonomous Region, causing three people injured. The earthquake effected areas mainly included 25 townships and towns, plus Hutubi County and Manas County in Changji, Hutubi and Manas. The total effected area is 12,450km². In this paper, we summarize the seismo-tectonic background and geomorphic features of the earthquake zone. Under the guidance of the standard "The Earthquake Site Works-Parts 4:Assessment of Direct Loss", the damage to buildings and lifeline systems with various structural types are introduced, and we ultimately estimate the direct economic losses to mud-wood houses and the destruction of brick-wood houses. Our results indicate that "The Urban and Rural Seismic Safe Housing Project" played a key role in reducing this earthquake disaster.     

2021年云南漾濞MS6.4地震前后主动源观测走时数据的变化

基于2021年5月21日漾濞M_S6.4地震震中附近50 km范围内15个地震观测台站记录的2020年11月1日—2021年5月30日的气枪震源信号,采用互相关时延检测技术提取这15个台站各自稳定震相(Sg震相)的走时变化时间序列,并对漾濞M_S6.4地震前后各台站的走时变化特征进行分析。结果表明:(1)漾濞M_S6.4地震前10天左右,有4个台站走时开始出现异常,其中,Ey211和Ey213台走时呈"V"型变化结构,Ey210和CHT台走时呈上升趋势。(2)漾濞M_S6.4地震后短期内,大部分台站走时出现了明显的趋势性变化,以维西—乔后—巍山断裂为界,断裂带两侧台站走时变化趋势存在明显差异,断裂以东的EYA、HDQ、YSW09台走时呈上升趋势,变化最为显著的为HDQ台,走时差变化量为0.067 s;而断裂带以西的所有台站在漾濞M_S6.4地震当天(或震后1～2天)开始出现明显趋势性下降,走时下降持续时间在4～9天间,走时差变化量在-0.053～-0.201 s间,其中走时差下降量最大为53 285台,最小为CHT台。     

Study of the Change in Wave Velocity Ratio before and after Two Strong Earthquakes Using Airgun Source Data

Using the signals excited by the large-volume airgun source at the Binchuan transmitting seismic station from January to June, 2016, arrival-time data was acquired at four stations near the epicenter of the Eryuan M_S4.5 and M_S4.0 earthquakes on February 8, 2016, as well as the epicenter of the Yunlong M_S5.0 and Eryuan M_S4.6 earthquakes on May 18, 2016 through the waveform cross-correlation technique. The wave velocity ratio of the four stations was calculated using the single-station method. At the same time, the b-value and the focal mechanism consistency parameters of the study area were also calculated. The results show that:(1) the wave velocity ratio of each station experienced a process of decline-recovery-fast rise before the two strong earthquakes, and a significant quasi-synchronous rapid rise occurred within 3-12 days before the earthquake; (2) the timing of the rapid rise of the wave velocity ratio of the four stations before the Yunlong M_S5.0 and Eryuan M_S4.6 earthquakes were related to the epicentral distance. The station which observed the earliest increase in rapid rise is the farthest one from the epicenter, and the station where the rapid rise appeared in the latest is closest to the epicenter; (3) the form of change of the wave velocity ratio before the earthquake was different between stations located at different directions in the epicenter area; (4) the b-value and the focal mechanism consistency parameter which is commonly used to characterize the stress level both showed a downward trend before the two strong earthquakes, and were consistent with the change in the wave velocity ratio. According to the preliminary analysis, the wave velocity ratio obtained by using airgun source can better reflect the change in the stress state of the underground medium.     

2016年新疆呼图壁6.2级地震房屋震害及成因浅析

对2016年12月8日新疆呼图壁6.2级地震灾区范围内不同结构类型房屋的震害资料进行了整理,分析了震害原因,探讨了该次地震中房屋震害的特征,得到了一些初步结论,并对地震灾区的恢复和重建提出了相关建议。     

Study on Seismic Damage to Buildings from the 2016 Hutubi MS6.2 Earthquake

Based on the field investigation of the building types and damage caused to them by the Hutubi M_S6.2 earthquake on December 8, 2016, we analyzed the damage characteristics and causes for different types of buildings. In conclusion we put forward some suggestions for the restoration and reconstruction in the earthquake affected area in future.     

Using Airgun Source Signals to Study Regional Wave Velocity Changes before and after the Yunlong MS5.0 and Yangbi MS5.1 Earthquakes

On the basis of the airgun source signals recorded by the stations from January, 2016 to June, 2017, we use cross-correlation detection technology to obtain the characteristics of the stable phase travel time change of each station. We used the Yunlong M_S5.0 and Yangbi M_S5.1 earthquakes as samples. According to regional characteristics, 13 stations with high signal-to-noise ratios and complete data were selected (including 3 fixed stations and 10 active source stations). They are divided into four regions, and on the basis of the GNSS baseline data, the characteristics of regional wave velocity changes before and after the earthquake are analyzed. The results show that the station phase travel time change and the regional stress characteristics represented by the GNSS baseline data have good correlation in the short-term. Due to different degrees of regional stress, there are differences in the travel time changes of different stations in the four regions. Before the Yunlong M_S5.0 and Yangbi M_S5.1 earthquakes, with regional stress adjustment, there is an upward trend in the travel time changes of related stations in the adjacent areas of up to 0.02s. The difference is that there are differences in the time nodes and duration of the travel time anomalies, and there is a reverse descent process after the Yangbi M_S5.1 earthquake. There are different degrees of travel time fluctuations in the relevant stations before and after the two earthquakes, but the fluctuation range before and after the earthquake was small. Compared with the water level change of the reservoir, the adjustment of the regional stress is more likely to have a substantial impact on the travel time changes of the relevant stations.     

Study on S wave splitting in Dayao earthquake sequence with M=6.2 and M=6.1 in Yunnan in 2003

Introduction In seismology, medium isotropy and anisotropy is defined by the direction of seismic wave propagation. If the seismic wave velocity does not vary with the direction, the medium is isotropy, whereas it is anisotropy. Recently, the study of anisotropy in crack medium becomes a focus forseismologists. Crampin (1978) made a deeply research on crustal anisotropy and put forward a theory of extensive dilatancy anisotropy (EDA) that there are a lot of cracks parallel to the hori- zonta…     

利用祁连山主动源资料研究2016年门源6.4级地震前后波速变化

采用叠加、互相关、插值拟合等方法对祁连山气枪主动源台网数据进行处理,针对2016年1月21日青海门源6.4级地震前后气枪激发地震P波、S波震相的走时变化特征进行了分析,结果表明,地震前约6个月时,震中附近3个台站的相对走时出现下降变化（走时减少）,至震前约3个月时低值异常恢复正常,之后再次出现走时下降变化,地震即发生于走时变化恢复过程中。S波走时变化最大下降幅度达18ms,震后走时变化逐渐恢复正常,且3个台站变化趋势较为一致,其中,距震中最近的台站的S波走时变化最明显（ZDY38台）,较远台站的走时变化幅度较小,其变化特征与震源区位置有关。走时缩短意味着速度增加,可能与区域应力积累间存在一定的关系。