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101.
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. 相似文献
102.
岩相和储层物性参数是油藏表征的重要参数,地震反演是储层表征和油气藏勘探开发的重要手段.随机地震反演通常基于地质统计学理论,能够对不同类型的信息源进行综合,建立具有较高分辨率的储层模型,因而得到广泛关注.其中,概率扰动方法是一种高效的迭代随机反演策略,它能综合考虑多种约束信息,且只需要较少的迭代次数即可获得反演结果.在概率扰动的优化反演策略中,本文有效的联合多点地质统计学与序贯高斯模拟,并结合统计岩石物理理论实现随机反演.首先,通过多点地质统计学随机模拟,获得一系列等可能的岩相模型,扰动更新初始岩相模型后利用相控序贯高斯模拟建立多个储层物性参数模型;然后通过统计岩石物理理论,计算相应的弹性参数;最后,正演得到合成地震记录并与实际地震数据对比,通过概率扰动方法进行迭代,直到获得满足给定误差要求的反演结果.利用多点地质统计学,能够更好地表征储层空间特征.相控序贯高斯模拟的应用,能够有效反映不同岩相中储层物性参数的分布.提出的方法可在较少的迭代次数内同时获得具有较高分辨率的岩相和物性参数反演结果,模型测试和实际数据应用验证了方法的可行性和有效性. 相似文献
103.
由于地表电阻率法受到浅地表局部异常体的干扰,反演精度受到影响,井中装置数据资料参与反演虽然可以减小浅地表局部异常体的干扰,但是由于钻井位置的局限性,数据量得不到保障,也会导致反演精度降低.为此,本文开发了一套结合地表、地-井、井-地和井-井装置数据的三维联合反演算法.首先,利用有限差分法实现正演模拟,采用非线性共轭梯度法(NLCG)恢复电阻率结构;其次,调用Message Passing Interface(MPI)函数库加速正演模拟和灵敏度矩阵运算,当开辟12个进程时,反演程序获得最大加速比4.51;最后,通过合成数据和实测数据算例证明该反演算法的有效性,也证实了多种装置组合数据体反演结果明显优于单一地表装置数据体反演结果. 相似文献
104.
The Chaohu-Tongling area in Anhui Province is a typical moderate-to-strong earthquake active area in the mainland of China. Four earthquakes occurred in this area, displayed as a NNE-trending zonal distribution, including the 1585 M5(3/4) Chaoxian earthquake and the 1654 M5(1/4) Lujiang earthquake, which formed a striking moderate-to-strong seismic activity zone. Field survey, shallow geophysical prospecting, drilling data, collection and dating of chronology samples and comprehensive analysis of fault activity indicate that the Fanshan, Xiajialing and Langcun faults are not active since Quaternary. The NNE-trending Tongling Fault is a buried middle-Pleistocene fault, but it can produce moderate-to-strong earthquakes and control the evolution and development of three en echelon geologic structures. The intensity of the four earthquakes is characterized by southward progressive decrease, which is in accordance with the characteristics that the subsidence range of Wuwei Basin is obviously larger than that of Guichi Basin to its south since late Cenozoic. In terms of deep structure, the characteristics of spatial distribution of Tongling Fault indicate that it corresponds to a NNE-striking Bouguer gravity anomaly gradient belt. So there is a spatial correspondence between the middle-Pleistocene Tongling Fault, the en echelon structures, the differential movement of the neotectonics, the Bouguer gravity anomaly gradient belt and the moderate-to-strong seismic activity belt in the Chaohu-Tongling area, indicating that they should be the tectonic indications of occurrence for moderate-to-strong earthquakes. 相似文献
105.
106.
鄂尔多斯地块紧邻青藏高原东北缘,位于华北克拉通的西部,在我国中生代、新生代以来东部地区的构造活动中起到了重要作用.对鄂尔多斯及其周缘地区的研究可以提供有关华北克拉通的形成、演化和破坏过程的重要信息.本文选取了纵贯鄂尔多斯的107.6°E附近南北剖面上的44个流动地震台站进行分析,采用接收函数方法,进行Kirchhoff偏移成像,并且结合在该区域内前人的地震面波频散进行联合反演,获得剖面下方的地壳内部精细结构.研究结果显示:(1)莫霍面在鄂尔多斯北部较平缓,约45km深;在鄂尔多斯南部有所加深,达到50km;其北边的河套盆地的地壳厚度约为50km;南边的渭河盆地到秦岭地区及四川盆地的地壳厚度从约为40km增厚到47~50km.(2)河套盆地下方存在大规模的低速异常,最深可达25km,反映了其显著的拉张构造和沉积历史.(3)秦岭造山带下方的低速异常对应于其主要为长英质的地壳组分,可能是由于中生代的拆沉作用导致的地壳下部基性岩石层的缺失.(4)以38°N为界的鄂尔多斯地块,南北部地壳速度结构存在差异,可能表明了这两部分经历的构造历史不同. 相似文献
107.
为提高梁式结构损伤诊断的效率,提出一种基于类柔度差曲率和频率摄动的结构损伤识别方法。首先根据结构振动理论,研究广义柔度矩阵计算公式;再利用模态柔度对结构损伤灵敏性高的优点,改进基于柔度差曲率的损伤定位指标,定义类柔度差曲率LCFC损伤指标,并初步识别损伤;最后基于矩阵摄动进行结构损伤识别结果确认。考虑多种损伤工况,对一简支梁结构进行损伤识别数值模拟验证。结果表明:仅使用一阶模态,建立的类柔度差曲率LCFC指标对梁式结构损伤定位具有良好的诊断效果,且计算工作量小;对于含边界损伤单元的多损伤工况,当损伤程度大于10%时,LCFC指标识别有效;当损伤程度不大于25%时,各工况二阶摄动识别结果精度较高,相对误差较一阶摄动结果明显降低,证明了该方法的实用性、有效性和精确性。 相似文献
108.
增强现实中的跟踪注册技术一直是研究的重点和难点,而地下矿道和巷道内亮度低,产生的图像较昏暗,车载相机快速运动和抖动,对传统的基于特征匹配的跟踪注册提出了挑战。本文从提高增强现实中跟踪注册稳健性和精度出发,采用基于Retinex改进的方法增强昏暗图像的亮度,同时利用基于对抗神经网络的方法恢复运动模糊图像。首先提取图像ORB特征,实现初始化;然后根据跟踪特征点的数量,开启图像增强和图像恢复线程,提高特征点提取质量和数量。在数据集和真实模拟场景下的试验结果显示,跟踪精度提高了12%左右,在低亮度和含有轻微模糊的情况下,跟踪注册稳健性也有显著提高。 相似文献
109.
110.
作为移动社交网络的主体,人们移动带来的位置轨迹不仅记录了人的行为历史,也记录了人与社会的交互活动信息。移动社交网络中位置轨迹数据的分析与利用为解决城市问题提供了一种新的思路。本文概述了轨迹数据可视分析中的几种方法,总结了轨迹数据可视分析研究中存在的问题和面临的挑战。 相似文献