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1.
汶川地震余震活动固体潮调制的统计分析   总被引:3,自引:0,他引:3  
李金  蒋海昆 《中国地震》2011,27(4):363-375
基于Schuster检验对汶川地震余震受固体潮的调制触发情况进行了系统的研究,包括对引潮力、潮汐应力和潮汐库仑破裂应力等触发地震情况的分时段分区段研究.结果表明,汶川北段2008年7月底至8月初的一组强余震受潮汐触发明显,引潮力、潮汐正应力及潮汐库仑破裂应力经Schuster检验平滑后均得到基本一致的结果.此外,汶川余震受半月潮的调制非常明显,北段余震多发生于上、下弦时段,南段地震多发生于上、下弦和望时段.  相似文献   

2.
近期天山地震带地震活动固体潮调制的统计分析   总被引:1,自引:0,他引:1  
利用Schuster检验方法,以潮汐体应力为计算量,采用2010年1月1日至2012年8月31日天山中东段ML≥2.0的地震数据,对天山地震带地震活动受固体潮触发情况从时、空两方面进行统计分析。研究结果显示,Schuster检验p值时间窗平滑结果与天山地震带较强地震的发生对应较好,尤其是2011年11月1日尼勒克6.0级地震之前很长一段时间,Schuster检验p值时间窗平滑结果一直低于潮汐触发地震的阈值0.05,而尼勒克6.0级地震发生后,该值迅速恢复到较高水平,反应了此次地震的发生与固体潮的密切关系;从Schuster检验p值空间窗平滑结果看,尼勒克6.0级地震也处于或接近潮汐调制触发地区。因而,从时、空两方面的检验结果看,尼勒克6.0级地震的发生受固体潮调制明显。  相似文献   

3.
引潮力与潮汐应力对强震触发的研究   总被引:9,自引:0,他引:9       下载免费PDF全文
本文讨论了在构造应力水平达到岩石破裂临界值时引潮力、潮汐附加应力的动态变化与地震序列之间的关系,选用了中国大陆1970年以来7级以上地震序列资料,分析了引潮力水平分量动态变化与强震发震时间之间的关系,结果显示在一定时空范围内前震、主震及余震序列发震时刻的引潮力存在优势方向,多数地震发震时刻与选取时段引潮力水平分量的方位角相位比平均值仅为35%;对于构造复杂地区,结果显示引潮力水平分量的方位角不仅存在一个优势方向,还明显存在其他优势方向,可能与发震构造有关.根据1966~1976年中国九大地震震源机制解计算潮汐正应力和滑动方向的剪应力及其变化率,结果显示多数地震发震时刻潮汐剪应力接近最大值.  相似文献   

4.
青藏高原东部及邻区地震断层面上的潮汐应力触发效应   总被引:4,自引:1,他引:3  
根据已发布震源机制解目录(哈佛大学CMT),将青藏高原东部及邻区划分为5个构造应力场分区,并对各分区的地震逐个计算其发震断层面上的固体潮汐正应力、剪应力、库仑破裂应力及相位角,分析潮汐应力分量对不同类型发震断层的作用效果及其随深度变化特征.基于库仑破裂应力判断准则,研究潮汐应力对各种类型地震的触发作用;基于Schuster检验方法,统计分析潮汐应力对各个震级档、不同构造类型地震的影响.综合运用上述两种分析方法,探讨潮汐应力对不同震级地震以及处于不同构造块体、发震断层、震源深度地震的触发机制.结果表明,潮汐应力对印度块体和拉萨块体的正断和逆断型地震,滇缅泰块体、印支块体和松潘-甘孜块体的走滑和斜滑型地震,川滇菱形块体的斜滑型地震均存在不同程度的触发效应,且触发效应的强弱依赖于震源深度、震级大小、发震断层类型及其所处区域构造应力场.  相似文献   

5.
选取1900 ~2012年中国大陆Ms≥7.0浅源地震为研究对象,计算日月潮汐在发震断层面引起的库仑破裂应力,确定潮汐相位角.通过Schuster检验,定量分析了中国大陆强震与日月潮汐库仑破裂应力之间的相关性.结果表明,具有震源机制解的57次强震中,71.9%的强震发生在潮汐加载相位区间,Schuster检验p值为3.83%,显示中国大陆7级强震与潮汐库仑破裂应力间存在很好的相关性.活跃期p值为4.56%,75.5%的地震发生在潮汐加载相位区间;而在平静期发生在加载相位区间的地震比例为50%.表明活跃期内的强震受潮汐库仑破裂应力的加载触发更为显著.  相似文献   

6.
以云南大姚、姚安及其附近地区8个M5.0地震序列为研究对象,计算了主震震源断层上的潮汐应力,并通过Schuster潮汐相位角统计检验,分析了该地区地震活动与潮汐应力的触发相关性,进一步确认两者的潮汐应力触发关系。结果显示,7个地震序列的P值小于5%,6个地震序列的潮汐库仑破裂应力为正值。考虑到震源参数的不确定性,8个M5.0地震序列中,至少5个地震序列与潮汐应力存在一定的触发相关性,说明潮汐应力对该地区地震活动具有一定的潮汐触发作用。  相似文献   

7.
潮汐触发地震研究进展综述   总被引:3,自引:0,他引:3  
李金  蒋海昆 《地震》2011,31(4):36-47
对近年来国内外潮汐调制触发地震研究进行了系统综述.介绍了月相与地震活动的关系,日月引潮力及其分量对地震触发的情况,基于大样本统计的潮汐触发地震研究等内容.月相与地震活动的简单对应是对潮汐触发地震的初步研究,调制比是对这一现象的定量化描述.潮汐应力分解及对地震活动影响的研究,则是从力学的层面揭示两者之间的可能关系.大样本...  相似文献   

8.
本研究通过反演241,561条纵波和209,363条横波高质量的地震走时数据,获得了鲜水河、安宁河断裂带的P波、S波以及泊松比的三维结构模型,并结合相位分析与Schuster测试讨论了该断裂带上地震事件的触发与其深部构造以及固体潮所产生的应力变化三者之间的关系.结果表明,鲜水河—安宁河断裂带26.5°N、28°N、29.5°N以及31.5°N四个位置附近存在低速、高泊松比异常,可能暗示着深部流体(包括部分熔融物质)的上涌.这些大范围分布的流体提高了孕震层的孔隙流体压力,削弱了断层面之间摩擦力,在鲜水河—安宁河断裂带形成了一些具有高度地震活动性的区域.此外,相位分析与Schuster测试的结果表明,鲜水河—安宁河断裂带附近的地震触发与固体潮剪切应力的变化密切相关.综合分析的结果表明,固体潮与构造应力对地震触发可能存在某种“合”的关系.在分布着大量流体的区域,地震事件可能对固体潮更加敏感.  相似文献   

9.
云南地震的潮汐应力触发机制及相关天体位置图像   总被引:10,自引:5,他引:10       下载免费PDF全文
通过计算云南163个地震震源处沿地震主应力方向的潮汐应力分量,分析了地震的潮汐应力触发力学机制.结果表明,所研究的地震中有62%受到了潮汐应力的触发作用. 在此基础上,对受到潮汐应力触发的地震发震时的天体位置特征进行了研究,得到了具有潮汐应力触发物理基础的地震时的月日黄经差、月日赤纬和月日天顶距的分布图像.图像显示,云南地区的地震在新月期间和上下弦附近较易受到潮汐应力的触发;受到潮汐应力触发作用的地震发震时刻的月日赤纬有明显的密集分布条带特征,地震频次在月、日天顶距分别为30°~140°和20°~140°范围内为平均优势分布区间.  相似文献   

10.
分析甘肃岷县M_S6.6地震前后潮汐变化发现,发震时刻引潮力处于最低相位点,显示引潮力的诱震属于典型逆冲断层作用类型。以潮汐周期为时间指示,利用NOAA卫星地面长波辐射(OLR)数据,分析震中及其邻近区域(30°~40°N,90°~110°E)地震前后(7月17~25日)地面长波辐射值的连续变化状况,结果显示,震前仅震中及其相关联断裂附近OLR发生了显著且连续的异常变化,在时间上经历了起始增温—异常加强—峰值—衰减—发震—平静的演化过程;在空间上异常区域覆盖震中,与汶川地震引发的应变积累正影响区之南北地震带北段基本吻合;在形态演化上,表现出沿断裂带分散—汇聚—分散的破裂过程,并与岩石应力加载破裂的初始微动破裂—扩张破裂—应力闭锁—地震爆发—恢复平静阶段的力学过程完全吻合。这可能预示该地震发震前后天体引潮力对处于临界状态的活动断层具有诱发作用以及长波辐射异常在一定程度上对地震构造应力应变过程辐射进行表征。  相似文献   

11.
A statistical analysis on earthquake activity in the Kashi-Wuqia intersection area triggered by earth tide is done by Schuster's test and the Permutation test on daily and monthly scales. The north-south, east-west component of the tidal force and tidal body stress are chosen as the tidal curve in the daily scale. The results show that most of the earthquakes occurred near the maximum 0° of the three kinds of tidal curves, the predominant tidal phases of the earthquake are - 5. 86°, 6. 60° and - 15. 52°, and the frequency of the earthquakes increases with the increase of the tide; with three kinds of tidal curves (the north-south, east-west component of the tidal force and tidal body stress ), the Ps of Schuster's test for all the earthquakes is 10. 52 %, 2. 40 % and 2. 06 %, and the pp of the Permutation test is 10. 90%, 2. 40% and 2. 06%, and the results ofps andpp based on the east-west component of the tidal force and tidal body stress are below the threshold of 0. 05 that tidal triggering of earthquakes. In the monthly scale, both the Ps and pp are very low ( close to 0 ), far below the threshold of 0. 05 of tidal triggering of earthquakes, and the predominant tidal phase for earthquake triggering is - 18. 95°, close to the maximum 0° ( new moon and full moon) of the earth tide in monthly scale. Regarding the statistical test result of tidal triggering of earthquakes, a preliminary explanation is given as to why the trigger effect in the east-west direction is greater than that in north-south direction.  相似文献   

12.
A series of housing collapses and other serious damage was caused by the 2008 Wenchuan MS 8.0 earthquake in the seismic intensity Ⅵ areas of the Loess Plateau, which is hundreds of kilometers away from the epicenter, and which showed a remarkable seismic intensity anomaly. The seismic disasters are closely related to the seismic response characteristics of the site, therefore, the systematic study of the far-field seismic response law of the Wenchuan earthquake in the Loess Plateau is of great significance to prevent the far-field disaster of great earthquake. In this paper, the seismic acceleration records of several bedrock stations and loess stations from the seismogenic fault of the Wenchuan earthquake to the Loess Plateau were collected, and the attenuation law of ground motion along the propagation path and the characteristics of seismic response on the loess site are studied, and the mechanism of amplification effect of ground motion is analyzed based on the dynamic feature parameters of the loess site obtained through the HVSR method. Taking a typical loess site of thick deposit as the prototype, a series of shaking table tests of dynamic response of loess site models with different thicknesses were carried out. Amplification effect, spectral characteristics of acceleration in model sites were analyzed under the action of a far-field seismic wave of the Wenchuan earthquake. The results show that seismic attenuation on the propagation path along the NE strike of the seismogenic fault to the Loess Plateau is slower than that in other directions, and the predominant period range of ground motion on bedrock site of the Loess Plateau presents broadband characteristics. Because the natural periods of loess sites with thick deposits are within the predominant period range of bedrock input wave, loess sites appear significant amplification effect of ground motion, the horizontal acceleration of ground motion exceeds 0.1 ?g, the seismic intensity reaches 7°. The thicker the loess deposit is, the more significant the change of spectral characteristics of ground motion on loess sites, and the narrower the predominant period range of ground motion becomes, and the closer it is to the natural period of loess sites. Therefore, for some old houses on thick loess sites, the poor seismic performance and strong seismic response eventually led to their collapses and damages because their natural periods are very close to the predominant period of ground motion of the Wenchuan earthquake on thick loess sites; For these damaged high-rise buildings, the resonance effect might be the main reason for their damages because their natural periods are included in the predominant period range of ground motion of the Wenchuan earthquake on thick loess sites.These research results would provide a basis for seismic disasters prediction and evaluation and seismic design of construction engineering in the Loess Plateau.  相似文献   

13.
汶川地震前地脉动低频波动现象及其应用的初步研究   总被引:2,自引:0,他引:2  
通过对距离汶川地震余震区较近的武都地震台震前连续记录资料的傅里叶频谱特征分析,发现在震前临震阶段,频率为0.1~0.3Hz的地脉动幅值出现快速、持续地增大现象;连续跟踪观测和试验表明,该现象在2008年7~9月间发生的多次地震前在多个台站出现,这种现象具有重现性,在时间上具有持续性,在空间上由震中及其附近或某个"位置"向外围扩散.对该特殊频率波动的物理本质、与震源和孕震动力学过程的关系等研究有可能对临震预测具有意义.  相似文献   

14.
The purpose of this study is to determine the possible trends in annual total precipitation series by using the non-parametric methods such as the wavelet analysis and Mann-Kendall test. The wavelet trend (W-T) analysis is for the first time presented in this study. Using discrete wavelet components of measurement series, we aimed to find which periodicities are mainly responsible for trend of the measurement series. We found that some periodic events clearly affect the trend of precipitation series. 16-yearly periodic component is the effective component on Bal?kesir annual precipitation data and is responsible for producing a real trend founded on the data. Also, global wavelet spectra and continuous wavelet transform were used for analysis to precipitation time series in order to clarify time-scale characteristics of the measured series. The effects of regional differences on W-T analysis are checked by using records of measurement stations located in different climatic areas. The data set spans from 1929 to 1993 and includes precipitation records from meteorological stations of Turkey. The trend analysis on DW components of the precipitation time series (W-T model) clearly explains the trend structure of data.  相似文献   

15.
本实验用超声地震模型实验模拟观测,滇西地震实验场地质构造格架对地震波波速的影响。模型为1米量级。模型与原型地质的比为1∶470000。实验模型有两块,一块为均匀无构造模型,另一块为有滇西实验场主要地质构造格架模型。实验对两种模型的P波速进行了比较,给出了以模型中心为观测点以及以昆明、中甸、下关和渡口为观测点,模拟震中距为50公里、100公里、150公里和200公里圈上P波波速变化的背景场。这一实验是用物理模型模拟研究复杂地质构造格架对地震波波速影响的首次方法探讨。  相似文献   

16.
横穿龙门山地震反射剖面系列探测是WFSD工程中的一项重要研究内容.通过WFSD-1先导孔区二维反射地震的观测方法研究和试验,实现了预期目标:(1)在震后恶劣的天气、陡峭地形和地表严重破裂、破碎、滑塌等困难条件下,获得了WFSD工程首条分辨率较高的二维反射地震剖面;(2)从地学研究目的出发,结合龙门山地区的复杂地震地质条...  相似文献   

17.
高华根 《华南地震》1991,11(4):39-44
台湾地震带是我国地震活动性最高的地区,其东部海域曾发生过两次8级特大地震。本文根据灰色系统理论,利用台湾地震东带1945-1990年期间每3年中的最大地震发生的间构成的序列,建立了台泻强震(Ms≥7.5)的灰色拓扑预测模型:∧/X^(1)(t 1)=(17.0 271.81)e^0.066119t-271.81结果表明,本带可能在1994年-1996年段再次发生强震。经模型检验结果表明,其拟合精度属第一级“好”。  相似文献   

18.
应用回归分析和切比雪夫拟合二种方法,根据验潮资料研究了华南沿海海平面的变化速率,进而结合区域研究近20年来华南海平面的变化特征,并讨论了将其用于地震趋势分析的可能性。  相似文献   

19.
孔隙砂岩力学性质随埋深变化的三轴试验研究   总被引:1,自引:0,他引:1  
针对取自吐-哈盆地中侏罗统油储地层砂岩(J_(2s))进行了三轴压缩试验,设计了不同的温度、压力及含水组台条件来模拟地层埋深对岩石力学性质的影响.初步结果表明,J_(2s)砂岩的主要静态岩石力学参数(杨氏模量、抗压强度、抗剪强度、弹性极限应力.残余强度及最大轴向承载应变量等)都呈明显的“组合”变化.随着埋深增大(0-5000m),杨氏模量总体呈下降趋势,其余各量皆有不同程度的增加,还对温压组合条件下砂岩断面上的摩擦滑动性能进行了分析讨论.结果对油储工程稳定性研究及油储地层地球物理反演时地层弹性参数的选取皆具有一定的参考意义.  相似文献   

20.
The paper introduces the steps and methods of multi-approach,multi-level exploration of buried faults in thick Quaternary sediment regions by taking the test exploration of the Yinchuan active fault as example.Based on the comprehensive analyses of previous data,we choose the Xinqushao Village of Xingqing District of Yinchuan City as the test site for the comprehensive exploration.Firstly,we adopted shallow seismic investigation with group intervals of 10m,5m and 1m to gradually trace layer by layer the master fault of the Yinchuan buried fault from a deep depth to a shallow depth where drilling could be used.Then,with composite geological profile drilling,we determined the precise location and dip angle of the fault.The drilling show the buried depth of the upper offset point is 8.3m.Finally,large-scale trenching revealed that the actual buried depth of the upper offset point of the fault is 1.5m from the ground surface and there are paleoearthquake events of 5 stages.Combined with the preliminary result of corresponding sample age,we conclude the Yinchuan buried fault is a mid to late Holocene active fault.  相似文献   

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