地震潮汐触发

地震潮汐触发是指由潮汐引起的应力变化而触发地震的现象,对地震潮汐触发的研究可能为断层错动引发地震的条件提供有价值的线索,一直受到国内外研究者的关注,本文对相关研究方法和研究结果进行了简要介绍和评述。在早期,地震潮汐触发研究主要是在地震活动中寻找潮汐周期。随着研究的深入,运用统计检验方法对地震活动与潮汐之间的相关性进行严格检验。时至今日,地震是否被潮汐触发的问题仍然悬而未决。不过,有研究结果表明,在强震发生前数年,震源区地震活动往往受到潮汐触发,如果这个结果被证实,将为地震预测研究提供新的线索。     

潮汐触发地震研究进展综述

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。 大样本统计则从统计的角度研究潮汐对地震的关系, 众多统计方法中应用较多的是Schuster检验, 它将震源机制、 潮汐应力、 统计检验等因素综合考虑, 定量地分析潮汐对地震的触发作用。     

云南地震的潮汐应力触发机制及相关天体位置图像

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.     

近期天山地震带地震活动固体潮调制的统计分析

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M_L≥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。     

新疆喀什-乌恰交汇区潮汐触发地震活动的统计检验

基于Schuster检验及Permutation检验方法,对喀什-乌恰交汇区地震活动受固体潮触发情况进行日尺度及月尺度检验。其中日尺度分别选取引潮力南北分量、东西分量及潮汐体应力作为潮汐曲线。研究结果显示,该地区地震活动均较多的发生于3种潮汐的最大值(相位0°)附近,优势发震相位分别为-5.86°、6.60°以及-15.52°,且发生地震的频次随潮汐力的增大而增加;利用3种潮汐曲线(引潮力日尺度南北分量、东西分量以及潮汐体应力)对所有地震进行Schuster检验所得pS值分别为10.52%、2.40%以及2.06%,Permutation检验所得pP值分别为10.90%、2.40%以及2.06%,其中基于引潮力东西分量及潮汐体应力的pS、pP值均低于潮汐触发地震的阈值0.05。月尺度Schuster检验pS值及Permutation检验pP值结果均非常小(接近于0),远低于潮汐触发地震阈值0.05,优势发震相位φ为-1.91°,较为接近月尺度下的固体潮最大值0°(即农历朔、望)。对潮汐触发地震的统计学检验结果即东西向潮汐触发效应大于南北向触发效应的原因进行了初步解释。     

汶川MS 8.0地震前小震潮汐应力触发特征研究

<正>1研究背景地震是地球内部运动的一种力学过程,其动力来源于地球内部。但当震源区处于临界状态时,外界因素如固体潮等的影响在一定条件下可能会引起系统的突变而发生地震（Cochran et al,2004;Tanaka et al,2004;Cadicheanu et al,2007;Tanaka,2010）。针对潮汐触发地震的问题,国内外学者做了大量研究工作,主要集中在以下3个方面：一是对部分地区地震活动和月相的相关关系研究,结果显示,地震在某些月相附近发生的几率相对较高;二是基于潮汐应力分量的地震调制研究,通常是将潮汐应力分解为南北、东西、垂直3个方向,其中水平分量与地震的关系往往被作为研究的重点;三是利用一定的统计方法分析潮汐相位角,通过严格定量的大样本检验,其中Schuster检验应用较多,通过p值变化来反映潮汐与地震的关系。     

强震成组活动与潮汐力调制触发

本文应用构造场体成组震模型的研究结果，探讨了中国大陆Ms≥7．0地震的成组活动的引潮力的调制触发关系。研究表明：我国陆区7级以上强震明显受潮汐力的调制触发，且主要表现为对活跃期内（即成组发生的）7级强震的调制触发。平静期内的7级以上地震基本不受潮汐力触发，而活跃期内82．4％的7级强震发生在受潮汐力触发的月相期，比本底概率高出36．4％。因此，潮汐力的调制触发对于强震活跃期的判断和活跃期内强震的临震（时间）预测有实际意义。文章还分析了潮汐力触发与强震活动的区域动力学环境之间的关系，并用构造场体成组孕震模型讨论了潮汐力对强震活动触发作用的力学机制。     

云南大姚、姚安及附近地区地震活动与潮汐应力的触发关系

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。     

南北地震带潮汐触发地震的统计学证据

自19世纪90年代以来,潮汐是否会触发地震这个问题一直备受关注.本研究选用1970年1月1日至2017年5月31日期间南北地震带(20°N—40°N,97°E—105°E)M_L≥2.0地震目录资料,通过测量南北地震带地区地震事件与潮汐的相关性来研究潮汐是否能触发地震.选用完备性检测、G-C法、R/S分析方法对原始地震目录进行预处理,分别构成未去除余震和去除余震每日地震数量时间序列,利用经验模态分解和快速傅里叶方法,对比分析了潮汐与每日地震数量构成的时间序列频谱特征.结果表明,在本文研究区域,两种每日地震数量时间序列均与潮汐的月潮周期、半月潮周期存在相关性,并且去除余震后的每日地震时间序列的优势频率更加集中,表现的相关性更好.此外,Schuster’s测试结果也进一步证明,研究区域地震活动性与固体潮汐存在显著统计相关性.     

潮汐应力-应变对某些地震序列的调制触发

对1960年以来中国大陆浅源地震序列与潮汐应变的相关分析表明, 某些地区某些地震序列, 包括前震序列、 前震-主震序列、 前震-主震-余震序列和主震-余震序列明显受到潮汐应力-应变的调制触发。 如龙陵地震的前震-主震序列, 邢台地震的前震-主震-余震序列、 唐山地震的主震-余震序列等。 这些地震序列受到潮汐力调制触发的特征明显, 对地震预测有意义, 并作了具体的叙述。 同时对地震序列受调制触发的机理作了初步的探讨, 指出不同类型地震序列的调制触发特征与孕育系统地质构造, 地震震源岩石性质和区域构造应力场方向以及地震破裂机制有关, 对地震机理和预测的研究有一定意义。     

Evidence of earthquakes triggered by the tidal force of the sun and the moon——On the temporal characteristics of the earthquakes in Xingtai,Hejian and Tangshan

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Evidence of earthquakes triggered by the tidal force of the sun and the moon

Studies by many scientists show that Hebei, China is an area with strong correlation between the tidal force and the occurrences of major earthquakes, the Xingtai earthquake of 1966, the Hejian earthquake of 1967 and the Tangshan earthquake of 1976 were triggered by the tidal force, in this paper the study on the common characteristics of their occurrence times confirms these facts. The computed times of maximum horizontal of the semi diurnal solid tide tidal force show that the occurrence times of the above mentioned earthquakes were close to the times of maximum horizontal tidal force of the semi diurnal solid tide at new moon or full moon. The Longyao earthquake of M=6.8, the Ningjin earthquake of M=7.2 and the Hejian earthquake of M=6.3 occurred tens of minutes after the maximum horizontal tidal force of the semi diurnal solid tides, and the Tangshan earthquake of M=7.8 occurred 16 minutes before the maximum horizontal tidal force. The tidal forces were directed to the west. This is their temporal characteristic. It is generally accepted that the 1969 Bohai earthquake of M=7.4 and the 1975 Haicheng earthquake were not triggered by the tidal force. These events did not show such characteristics. The temporal characteristics of the earthquakes indicate that the occurrences of these events were not random, but were controlled by the tidal force from the sun and the moon, and triggered by the tidal force. These facts agree with the triggering mechanism of the tidal force, are evidences of earthquakes triggered by tidal force.     

山东乳山震群遗漏地震检测及震源区活动特征分析

对震群活动特征的深入研究可以为区域地震危险性分析和地震活动趋势判断提供有效的依据,但受台网布局和震群位置的影响,地震目录中往往会遗漏一些地震,而地震目录的完整性将会影响震群活动特征分析的可靠性.因此,本文利用基于GPU加速的模板匹配方法对山东乳山震群2014年5月至2015年6月期间固定台站和流动台阵记录的连续波形进行...     

A SYSTEM OF CAPACITIVE HIGH-VOLTAGE PULSE RECHARGE/DISCHARGE AND ITS IMPLICATION ON EXPERIMENTALLY TRIGGERED EARTHQUAKE

An external small disturbance may trigger seismic events when the fault is in a critical state. The problems related with earthquakes triggered by the dynamic stress such as blasting loads, impact loads, volcanic eruptions and strong earthquakes, have usually drawn wide concerns in earthquake science, and the corresponding research contents are quite extensive, including earthquake triggering mechanisms, triggering earthquake uncertainty, aftershock triggering, and so on. Among them, experimental research is an important way to understand the stress triggering conditions and physical mechanisms, such as the influence of load disturbance on fault friction traits, the influence of periodic disturbance of tidal stress on fault instability, etc., all of which can be gained through experimental investigations. Among them, "how to trigger" is a basic scientific problem to increase the understanding of earthquake prediction theory, thus receiving more attention. There are also some studies that focus on "what happened after the trigger", that is, the sliding instability generated by the triggering method, and then the evolution characteristics of the sliding instability process. The well-known experimental study of the super-shear rupture process is conducted by using the electric explosion method to trigger the fault instability, and the high-speed camera records the super-shear rupture during the fault instability. This means that when the trigger source is controllable, it is possible to generate different types of instability processes, and then to explore which earthquakes will be triggered at different time and space positions under different stress states by means of active triggering. The study of stability analysis and instability process has important scientific significance.A stable system of capacitive high-voltage pulse discharge and recharge is one of basic techniques for studying the triggered earthquakes in laboratory. Based on the wire electric explosion method, this paper develops a controllable trigger experiment system. By designing a new capacitive high-voltage pulse charge and discharge system, while considering the actual needs of monitoring and system timing, multiple functions are integrated into one system. Functionally, in addition to realizing the dynamic loading and unloading function of the wire electric explosion method, the discharge process can be monitored, and the triggering, synchronization and timing signal output is performed with other observation systems, thus realizing the whole process monitoring of the dynamic disturbance action. After testing, the following functions are achieved:1)The voltage and current of the high-voltage charging power supply system can be automatically adjusted, and the system can be shut off after charging; 2)Control modes include manual and remote controls. These two modes can control the recharge, release and pulse discharge of the high voltage capacitor; 3)The system can produce multi-channel synchronous output, which satisfy multiple systems working together. In particular, the remote sensing method greatly improves the experimental maneuverability and security; 4)The system has multiple sets of gas discharge tube to trigger discharge, with a wide range of discharge voltage of 500~5 000V; 5)Roche coil resistance integral current detection can meet the transient resistance, large current detection. Test results indicate that this system has good repeatability and stability with the same discharge energy and discharge energy regulator, which is conducive to carry out single channel trigger of high-pressure discharge experiment. In short, the new charging and discharging system can meet the requirements of experimental study of triggering earthquake. In addition, this system can be used to generate the stress disturbance under certain static and dynamic conditions, and then judge whether this kind of mechanical conditions in active fault systems is currently stable.In short, a controllable single-shot discharge system is developed by a capacitive high-voltage pulse discharge system, which provides a good technical basis for experimental research on triggering earthquakes. In addition, the new system also has application significance:1)multiple triggering output can simultaneously start multiple systems and improve the efficiency of observation. Fault instability is a characteristic of transient response, so, its observation requires high-speed acquisition equipment, which is difficult to control on observation; the trigger system is controllable, with active synchronization observation using physical parameters; 2)stress disturbance can be triggered under static and dynamic loads to detect the safety and stability of the fault system with active trigger.     

调制模式、调制比预报方法应用朔望潮的理论依据

朔望潮触发和调制地震的发生已是一个基本事实,朔望潮即是半月潮幅度最大时段再迭加半日潮和全日潮。由于朔望潮量值大,所以它作用到震源系统上影响震源过程的７种效应也大,因而朔望潮与地震的相关性较好。由此作者认为用朔望潮比单纯用半日潮来判断震源过程的不稳定性更好,它可以回避震源地方的很多复杂问题而不影响预报地震的效能。