云南省昆明地区地震密集特征分析

发布时间：2019-04-17 12:11

【摘要】：地震活动性研究是通过对地震观测系统(如地震台网)记录到的或者历史资料中记载的地震事件发生的时间、空间和强度等基本的数据进行分析,总结出这些参数之间的规律的工作。无论是从空间还是时间尺度上,地震事件的分布都是极其不均匀的。在有些地方地震活动强烈,而在另一些地方地震活动则很微弱。通过地震活动特征分析,我们可以了解地震活动的基本规律,进而对大震强震的规律进行分析。地震所造成的破坏十分严重,因此对地震活动性的研究对地震危险性分析、历史地震事件的参数确定等具有实际意义。在地震活动性的研究中,许多研究者采用了多种方法对其进行研究。从研究方法的性质进行划分,地震活动性研究方法可以分为地震活动性定性研究方法和震活动性定量研究方法。在众多的研究方法中,区域网格点密集值算法是对地震活动特征分析的行之有效的方法。该方法提出后,经过多年的完善优化,已经应用于中国华北地区的地震活动性研究(王健,2001;王健等,2004;王健等,2004;王健,2007),并取得了显著成果。区域网格点密集值算法通过计算研究区域网格节点的地震密集值Vj并以此为依据对密集区域进行划分。在对密集区域的详细的时空分布进行研究后,该方法可以进一步分析密集区的类型以及成因,进而对整个研究区域的地震活动性特征建立整体的了解。此外,本文还针对区域网格点密集值法与大震强震的震中的关系进行了讨论,在一定程度上对1833年8级地震的震中经纬度进行了修正,并对研究区内可能遗漏的历史地震事件的大致位置进行了分析。在此基础上,本文为更加清晰地了解地震密集随时间的动态演化特征,提出了地震密集扫描图的方法。通过对该方法所提供的信息进行分析,本文发现地震密集随时间的动态演化特征表现为类似于“扩散”的特征,并将这种特征定义为“地震密集扩散”。通过研究地震密集随截止时间的变化特征,本文发现“地震密集扩散”具有一定的方向性。此外,在本文还针对强震前后地震密集的变化进行了分析,认为6级左右的强震发生前往往存在着相应的地震密集背景。最后,本文针对双差地震定位方法与区域网格点密集值算法的结合性进行了初步讨论,但由于相关数据较少,因此双差地震定位方法是否可以提高区域网格点密集值算法的精度还有待进一步讨论。
[Abstract]:Seismicity studies are based on the analysis of the time, space and intensity of seismic events recorded by seismic observation systems (such as seismic networks) or recorded in historical data. Summarize the work of the law between these parameters. The distribution of seismic events is extremely uneven both in space and on time scale. Earthquake activity is strong in some places, but weak in others. By analyzing the characteristics of seismic activity, we can understand the basic rules of seismic activity, and then analyze the law of strong earthquakes. The damage caused by earthquakes is very serious, so the study of seismicity is of practical significance to the analysis of seismic risk and the determination of parameters of historical earthquake events. In the study of seismicity, many researchers have used many methods to study it. The seismicity research method can be divided into qualitative seismicity research method and seismicity quantitative research method according to the nature of the research method. Among the many research methods, the regional grid point density algorithm is an effective method to analyze the seismic activity characteristics. The method has been applied to the study of seismicity in North China after years of improvement and optimization (Wang Jian, 2001; Wang Jian et al., 2004; Wang Jian, 2007), and remarkable achievements have been achieved in the study of seismicity (Wang Jian, 2001; Wang Jian, et al. 2004; Wang Jian et al., 2004; Wang Jian, 2007). The regional grid point density algorithm (Vj) is used to calculate the seismic density value (Vj) of regional grid nodes and divide the dense regions according to this algorithm. After the detailed spatio-temporal distribution of the dense area is studied, this method can further analyze the types and causes of the dense area, and then establish an overall understanding of the seismicity characteristics of the whole study area. In addition, the relationship between the regional grid point density method and the epicenter of the strong earthquake is also discussed in this paper. To a certain extent, the latitude and longitude of the epicenter of the 1833 earthquake with M = 8 have been corrected. The general location of the historical earthquake events that may be missed in the study area is analyzed. On this basis, in order to understand the dynamic evolution characteristics of earthquake density with time more clearly, a method of seismic intensive scanning map is proposed in this paper. Through the analysis of the information provided by this method, it is found that the dynamic evolution of earthquake density with time is similar to that of "diffusion", and this feature is defined as "earthquake intensive diffusion". By studying the characteristics of earthquake density with the cut-off time, it is found that the "earthquake-intensive diffusion" has a certain directivity. In addition, this paper also analyzes the earthquake-intensive changes before and after the strong earthquakes. It is concluded that the strong earthquakes with M _ S6 or so have a corresponding background of earthquake-intensive occurrence. Finally, the combination of double-difference seismic location method and regional grid point density algorithm is discussed in this paper. However, due to the lack of correlation data, this paper discusses the combination of two-difference seismic location method and regional grid point density algorithm. Therefore, whether the double-difference seismic location method can improve the accuracy of the regional grid point density algorithm remains to be further discussed.
【学位授予单位】：中国地震局地球物理研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P315

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