【作者】 崔仁胜；

【导师】 王洪体；

【作者基本信息】 中国地震局地震预测研究所 ， 固体地球物理， 2011， 硕士

【摘要】 地下介质特性变化信息对探索地震物理预测具有重要的意义,精密主动地震监测系统为动态观测地下介质物性变化提供了一种可能的途径。精密主动地震监测以精密控制震源为信号源,该震源具有输出大吨位力、精确控制频率和相位的特点,可长时间重复对地激发低强度信号,通过高精度的观测系统获得记录资料,采用专门的数据处理方法来提取地下介质特性信息。影响精密主动地震监测效果的关键在于震源信号质量及信号提取技术,本文从提高观测资料的信噪比和分辨率的角度来研究震源扫描信号设计和信号提取方法。在考虑到精密控制震源旋转特性的基础上,研究了多种扫描信号设计方案,提出了扫描信号设计的能量均衡原则和信噪比均衡原则,通过离散点拟合来生成扫描信号。通过实际计算表明,按照发射频谱、相关子波形态和发射能量三个方面的评价,离散点拟合扫描信号设计方法可以灵活设计出分辨率高的发射信号,对提高精密主动地震监测的震相信息分辨率具有实际意义。在信号提取方面本文研究并提出了加权匹配滤波方法来抑制短时突发噪声对精密控制震源信号提取的影响。通过评估记录中的噪声水平时间分布取得对应时段的权重,对噪声水平高的时段分配较小的权重,噪声水平较低的时段分配较大的权重,再进行加权匹配滤波,达到降低短时突发噪声对有用信号的影响、有效提高输出信号信噪比的目的。精密主动地震监测产生观测数据量十分庞大,需要合适的处理软件才能高效完成处理任务,为此本文探索在Linux环境下开发相关软件。本文基于GTK+图形库提出了适用于Linux环境下的图形用户界面软件实现方案。尝试开发了地震数据采集系统网络客户端、波形叠加和震相分析图形交互界面等软件,可交互便捷获取远程台站数据和处理大量主动地震观测数据。更多还原

【Abstract】 The temporal variation of subsurface medium has major significance for studying physical forecast of earthquake. The Precisely and Actively Seismic Monitoring system may supply an approach to observe dynamically the temporal variation of the physical nature in the subsurface medium. As a signal source in the Precisely and Actively Seismic Monitoring system, the Controlled Accurately Seismic Source (CASS) can stimulate the low-power signal repeat for a long time with features of radiating large-tonnage force and controlling the frequency and phase precisely. At observation stations, the signal is recorded by high-precision observation system, and improved the signal-to-noise ratio by special data processing method. The quality of sweep signal and the technology of the signal detection have important impact on the result of the Precisely and Actively Seismic Monitoring system. In the paper, we study the method of designing sweep signal and detecting the signals to improve the SNR and resolution of the observation data.Taking the rotational feature of CASS into account, various design methods of chirp signal for CASS are discussed. The energy balance principle and the signal to noise ratio balance principle are proposed , and a new method with fitting of discrete points to design sweep signal for CASS is given out in this paper. It is demonstrated that the new method is able to design chirp signal with better resolution assessed by the factors like the spectrum, the energy, and the wavelet of cross-correlation. It is practicable and meaningful in improvement of phase resolution in actively seismic monitoring.For detecting the signal of CASS, the weighted matched filtering method is studied and proposed in the paper, to suppress the effect of the short-time noise. A suitable weight is imparted to the signal segment by assessing the distribution of the short-time noise in these periods. Low weights are chosen for the periods with high noise level, and the signals with weights are filtered by the weighted matched filter in the purpose of reducing the impact of the short-time noise and improving the signal to noise ratio of the output signals.Large amount of the observational data can be obtained in operation of the Precisely and Actively Seismic Monitoring system, which require a specialized software to process efficiently. The method for developing software in Linux operating system is study in the thesis. The graphical user interface (GUI) software implementation based on GTK+ graphics library, which suits for Linux, is proposed. We tried to develop the network client of the seismic data acquisition system and the GUI software for wave superposition and phase analysis, which can obtain the observational data from the remote station and process the data from active seismic monitoring system friendly and conveniently.更多还原