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特大远震引起的形变观测变化图像 总被引：3，自引：0，他引：3
利用定点长水管倾斜仪、石英伸缩仪、金属摆倾斜仪、石英摆倾斜仪连续观测资料对特大远震引起的震时和震后形变效应进行了分析.分析结果表明定点连续形变观测台网能记录到不同方位地震的震时脉冲信号,其持续时间半小时到4小时;同时还能记录到一些地震的阶跃信号.水平摆倾斜仪（金属摆、石英摆）观测值的震后效应表现为大幅漂移,持续时间几天到一个月.对由特大远震引起的形变观测变化图像出现差异的原因进行了讨论.另外对震时阶跃变化图像、定点形变观测仪器长趋势的漂移项、观测台站所处的地质构造三者之间的关系进行了讨论. 相似文献
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简要介绍了新安江地震台JB型金属摆倾斜仪和VS垂直摆倾斜仪这两种模拟与数字地倾斜仪器进行记录的情况,并对模拟记录和数字记录的运行率、相关性、噪声水平、稳定性、观测精度等指标进行对比分析,找出数字化观测与模拟观测的差异,为地震台站进一步搞好数字化观测,提高观测精度提供依据。 相似文献
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1990年10月20日甘肃景泰Ms=6.2级地震前,兰州形变台水管倾斜仪(FSQ)、水平摆倾斜仪(SQ70B)、石英伸缩仪(SSY-Ⅱ)、和重力仪(GS11-150)的观测结果均有异常显示,本文介绍并分析了这些异常变化。 相似文献
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宁波地震台地倾斜模拟与数字观测对比分析 总被引：5，自引：1，他引：4
通过对宁波台地倾斜数字VS垂直摆与模拟JB水平摆倾斜仪2002年一年时间的并行观测和研究,认为在观测资料的连续性、稳定性、可靠性和观测精度上,VS垂直摆倾斜仪明显优于JB水平摆倾斜仪;在数据传输上,数字化仪器实现了远距离快速传输,有利于及时捕捉地震的短临信息,有利于资料共享。 相似文献
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Separation of diffracted from reflected events in seismic data is still challenging due to the relatively low amplitude of the diffracted wavefield compared to the reflected wavefield as well as the overlap in the kinematics of reflection and diffraction events. A workflow based on deep learning can be a simple and fast alternative, but using training data made by physics-based modelling is expensive and lacks diversity in terms of noise, amplitude, frequency content and wavelet. This results in poor generalization beyond the training data without retraining and transfer learning. In this paper, we demonstrate successful applications of reflection–diffraction separation using a conventional U-net architecture. The novelty of our approach is that we do not use synthetic data created from physics-based modelling, but instead use only synthetic data built from basic geometric shapes. Our domain of application is the pre-migration common-offset domain where reflected events resemble local geology and the diffracted wavefield consists of downward convex hyperbolic diffraction patterns. Both patterns were randomly perturbed in many ways while maintaining their intrinsic features. This approach is inspired by the common practice of data augmentation in deep learning for machine vision applications. Since many of the standard data augmentation techniques lack a geophysical motivation, we have instead perturbed our synthetic training data in ways to make more sense from a signal processing perspective or given our ‘domain knowledge’ of the problem at hand. We did not have to retrain the network to show good results on the field data set. The large variety and diversity in examples enabled to trained neural networks to show encouraging results on synthetic and field data sets that were not used in training. 相似文献
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ＣＺ－１型标定信号发生器是根据国家地震局“遥测地震台网观测技术规范“和对地震观测台站的要求而研制的。它可以在地震观测现场用于对地震计和放大记录系统标定测试,也可用于实验室对放大器、滤波器等进行测试和维修,与其它常规信号发生器相比,更能满足地震局系统的需要。 相似文献
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In order to study the seasonal variation of large volume airgun signals in Hutubi, Xinjiang, we analyzed 2,936 signals of airgun source excitations during 2015-2016 received by a seismograph on the bank of the excitation pool. Firstly, the RMS value of the signal amplitude and the daily average temperature were compared after linearly superimposing the signal in days, to analyze the influence of the surface ice cover on the excitation energy release of the airgun source. The result shows that the ice cover will reduce the excitation energy, and the thicker the ice cover is, the more obvious the excitation energy reduces. Secondly, the time-frequency analysis method was used to analyze the influence of the surface ice cover on the signal frequency. It is concluded that the existence of the ice cover has little effect on the signal frequency, but it will affect the intensity of the signal around 4Hz between 1-2s after excitation. The cause of these phenomena is that the ice cover affects the bubble oscillation, which in turn affects the energy conversion. The study shows that when using the cross-correlation delay method to calculate the wave velocity, the signals can be divided into two periods according to the daily average temperature:with or without ice cover on the upper surface of the excitation pool. This can help eliminate the influence of the source variation and improve the accuracy of the monitoring results. 相似文献
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针对电磁式可控震源地震数据的相关检测,研究发现,在地下结构复杂、基板-大地耦合不佳时,常规方法——基于震源控制信号或基板附近信号作为参考信号检测得到的地震记录中,存在子波到时误差和虚假多次波问题.本文分析了上述问题的理论原因,并提出基于重构激发信号的相关检测参考信号方法(Correlation Detection Reference Signal Based on the Reconstructed Excitation Signal,CDRSBRES).首先,利用直达波与其他地震波到时不一致的特点,从震源基板附近信号中分离、提取直达波.然后,利用直达波重构震源激发信号并作为参考信号对地震数据进行相关检测.最后,应用谱白化技术提高检测结果质量.数值模拟研究表明,重构激发信号与理想激发信号的相关系数为0.9869,达到高度线性相关,CDRSBRES方法检测的地震记录在子波到时和波形特征上均与模型相符.随后,在某金属矿区开展了可控震源对比实验.与液压式可控震源MiniVib T15000检测结果相比,电磁式可控震源PHVS 500的检测结果中:基于震源控制信号的检测结果存在子波到时误差约0.012s,对应垂向精度误差约11.16m;基于基板附近信号的检测结果部分区域出现虚假多次波,信噪比降低;而CDRSBRES方法的检测结果子波到时误差约0.001s,对应垂向精度误差约0.93m,波形特征一致,相同区域无虚假多次波.综上,本方法适用于电磁式可控震源地震数据的高精度检测,尤其对于地下结构复杂区域的高分辨率地震勘探具有重要意义. 相似文献
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低频电磁信号在地下电性结构探测中具有重要作用,经过长距离传播,信号衰减,可能被淹没于噪声中.利用多重自相关检测方法,对微弱低频电磁信号进行检测,并与自适应滤波法和离散小波变换法进行对比.利用Matlab对3种算法进行仿真研究.结果表明,多重自相关法能更好抑制噪声,有效检测微弱信号,检测性能优于小波变换法和自适应滤波法. 相似文献
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本文将多次波自适应相减问题表示为一个多道卷积信号的盲分离问题.利用2D卷积核来表示预测多次波和实际多次波之间的差异,并采用分离出的一次波信号的非高斯性最大化作为优化目标,我们提出一种基于多道卷积信号盲分离的多次波自适应相减算法.为了求解上述非线性优化问题,所提方法将其转化为一个迭代线性优化问题,采用迭代最小二乘方法加以实现.由于采用了多道卷积信号盲分离模型,所提方法能够适应预测和真实多次波之间在时间及空间上的变化.通过对简单模型数据、Pluto数据和实际数据进行处理,验证了所提算法的有效性. 相似文献
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光记录倾斜观测的时间服务很重要。根据观测工作实际的需要，优化设计并制作了时号灯自动备用电路装置。在原时号灯部分发生故障时自动启用备用时号灯，直到故障处理后为止，并以LED发光警示。提供了电原理图，介绍了工作原理、性能特点、使用效果。实践表明，该装置质优高效，价廉便用，可进一步提高观测质量，减轻工作负担，并可在地磁等光记录观测中应用。 相似文献
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在地震电磁学研究中,电流在地下的流动特征与构造关系是一个非常重要的问题.大范围观测站的分布和强电流源存在的格局为我们研究这个问题提供了机会.本文通过对青岛换流站接地极向地下注入2100~3004 A大电流时华北东部地区21个地电场台站观测的研究,深入认识了地电场信号变化实质.研究表明：①沿着郯庐断裂带方向、跨过郯庐断裂带西南方向、跨过郯庐断裂带北西方向能够记录到地电流信号的特征变化非常大,存在着明显方向性特征和“穴位”现象.②注入大地的电流强度越大,则在观测点记录到的地电流信号强度也越强.③本文研究区域里地电场信号的均匀度并不遵循均匀介质条件下的一般规律,说明地下介质电性非均匀性和各向异性特征明显.④大电流注入地下时能够较正确地反映信号源方位的台站较少,只有安丘台、大山台和新沂台所观测到的方位线可用于确定信号源的位置.本文从点电流源与台站测线布局构成的装置系统、大区域介质非均匀性、台站测区以及附近地区的介质细结构的影响三个方面,通过数值模拟,对上述特征进行了较深入的分析和解释. 相似文献
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Weak Seismic Signal Extraction Based on the Curvelet Transform 总被引：1，自引：1，他引：0
Seismic signal denoising is a key step in seismic data processing. Airgun signals are easy to be interfered with by noise when it travels a long distance due to the weak energy of active source signal of the airgun. Aiming to solve this problem, and considering that the conventional Curvelet transform threshold processing method does not use the seismic spectrum information, we independently process the Curvelet scale layer corresponding to valid data based on the characteristics of the Curvelet transform of multi-scale, multi-direction and capable of expressing the sparse seismic signals in order to fully excavate the information features. Combined with the Curvelet adaptive threshold denoising the algorithm, we apply the Curvelet transform to denoising seismic signals while retaining the weak information in the signal as much as possible. The simulation experiments show that the improved threshold denoising method based on Curvelet transform is superior to the frequency domain filtering, wavelet denoising and traditional Curvelet denoising method in detailed information extraction and signal denoising of low SNR signals. The calculation accuracy of the relative wave velocity variation of underground medium is improved. 相似文献