东北典型区域宽频带地震背景噪声成像研究

发布时间：2018-04-03 22:22

本文选题：背景噪声成像　切入点：瑞雷波　出处：《吉林大学》2017年博士论文

【摘要】：地震背景噪声层析成像即为通过对台站对间长时间的地震背景噪声进行互相关计算以获取台站对间的格林函数,进而获取面波频散信息,并进一步利用地震面波层析成像方法获得地球浅部的速度结构。宽频地震仪是利用地震背景噪声成像探测地下精细结构的必须设备,本文首先对吉林大学-仪器科学与电气工程学院研制的宽频地震仪布设在华南地区的数据记录进行了基于背景噪声的互相关计算和功率谱密度计算并进行了相应的分析:通过台站间互相关极其不对称结果分析得到噪声源主要来源于台站分布的东北方向;各台站间的背景噪声优势频率各有独特特征,其噪声功率谱密度高频成分有很强的日夜变化特征,该现象符合人类日夜活动规律,分析其原因为人为活动干扰所引起;各台站噪声功率谱密度低频成分特征基本一致,其低频成分可能是由海浪的作用等所引起。以上为自制宽频地震仪器的数据记录应用于深部探测算法研究中做了铺垫。利用国家地震台网和区域地震台网的宽频地震数据,对吉林省和辽宁省及辽宁省和渤海区两部分分别进行基本背景噪声成像的研究,对火山区,地热区、地震多发区及特殊地质的成像结果进行了分析和解释及推断。根据宽频地震台站分布特征,并考虑到射线分布的均匀性,因此两次成像研究其区域均覆盖了辽宁省地区。其中吉林省和辽宁省及附近区域的成像研究应用了61个宽频带地震台站2013年1年垂向分量的连续波形记录,本文给出了5s,7s,9s,14s,20s和30s周期的相速度分布图,并对其分布图进行了分析讨论,其中短周期(5-9s)瑞雷波相速度分布与地质构造特征具有较好的相关性。通过对三维SV波速度结构分析得到了如下认识:天池火山区近地表约12km内呈现低速异常,这可能与断裂构造异常发育和地壳中岩浆囊造成的地表热异常有关;天池西侧龙岗山下方存在低速层,推测也是由于深部岩浆的热传导使介质处于高温软化状态所致;近平行于敦密断裂镜泊湖地区及其西南部地壳中均呈现低速异常,根据地热发育背景及赋存条件,并结合三处钻井资料和镜泊湖地堑地热田推断出镜泊湖区为地热资源富集区,其西南部亦为下伏深埋热储;辽南地区2010-2015年浅源地震多发区位于地壳浅部低速区,同时与上地幔局部凸起带东南斜坡存在对应关系。辽宁省和渤海及附近区域的成像研究应用了73个宽频带地震台站2013年1年三分量(垂直分量,东西分量,南北分量)的连续波形记录,本文给出了9s,15s和20s的瑞雷波和勒夫波相速度分布图,并对其分布图进行了分析讨论。短周期(9s)瑞雷波和勒夫相速度分布相似,且与地质构造特征具有较好的相关性,两者成像结果也相互印证。通过对三维剪切波速度结构分析得到了如下认识:海城区和唐山区的小震多发生在地壳浅部,且位于高速和低速过度区及断裂带上或断裂带的延伸方向;渤海海域中部及北部沿郯卢断裂带地壳中下速度偏高,地壳底部莫霍面附近存在明显的高速薄层,这为深部物质沿郯庐断裂带上涌侵蚀地壳的提供依据。本研究对华南地区的数据处理也是为自制宽频地震仪应用于宽频台阵探测试验并进行背景噪声成像等相关数据处理做了铺垫。地震背景噪声的成像结果分析为实际地热勘探工作提供了参考资料;为分析地震孕育、地震的发生规律及地震构造背景提供了基本现象;对研究区特殊地质构造特点及深部动力学过程等研究提供一个参考。
[Abstract]:Seismic tomography is the background noise by calculating the cross-correlation of seismic background noise for long time to obtain the stations in between the Green function, and then obtain the surface wave dispersion velocity structure information, and further use of seismic surface wave tomography method for shallow earth. Broadband seismograph is the use of seismic background noise imaging detection equipment must be underground fine structure, based on the layout of broadband seismic instrument - Jilin University School of Instrument Science and electrical engineering in the Southern China region of the data records of the background noise cross-correlation calculation and power spectral density is calculated and analyzed based on the cross-correlation between stations is extremely asymmetrical result of noise the source mainly comes from Northeast direction of station distribution; background noise dominant frequency of each station between each have unique characteristics, the noise power spectrum The density of high frequency components and characteristics is very strong, which is in line with the law of human activities day and night, analyze the reasons for interference caused by human activities; the station noise power spectrum of low frequency component feature density is basically the same, its low-frequency components may be caused by the wave effect caused by above. Application of self-made broadband seismic data recording instrument it is the foundation to research the deep detection algorithm. Using the broadband seismic data from the national seismic network and regional seismic network of Jilin Province, and Liaoning province and Liaoning province and Bohai District, the two part of the study were the basic background noise on imaging, volcano area, geothermal area, the earthquake prone area and special imaging the geological analysis and interpretation of the inference. And according to the distribution characteristics of broadband seismic stations, and considering the uniformity of radiation distribution, so the two research areas are covered by the imaging of Liaoning Province The imaging study area. Jilin province and Liaoning province and neighboring areas using 61 broadband seismic stations in 2013 1 years of continuous vertical waveform components, this paper presents 5S, 7S, 9s, 14s, 20s and 30s cycle phase velocity distribution, and the distribution is discussed. The short period (5-9s) Leibo Rui phase velocity distribution and geological structure has a good correlation. Based on the analysis of three-dimensional SV wave velocity structure as follows: the Tianchi volcano area is about 12km in the near surface low velocity anomaly, which may be related to surface heat fault abnormal development and crustal magma caused by abnormal on the west side of Longgang mountain Tianchi; under the low velocity layer exists, that is due to thermal conduction of the deep magma in the medium high temperature softening state caused by; nearly parallel to the Dunmi fault area of Lake Jingpo and southwest of the crust appears abnormal low Often, according to the background and conditions of occurrence and development of geothermal energy, combined with three drilling data and Lake Jingpo graben geothermal field inferred Lake geothermal resources appear Bo rich region, the southwest is also a deep reservoir beneath the southern Liaoning; 2010-2015 years of shallow earthquake prone zone is located in the shallow crust low velocity region, at the same time with the southeast slope and upper mantle convex relationship. The imaging research of Liaoning province and Bohai and nearby areas using 73 broadband seismic stations in 2013 1 years three component (vertical component, component, component of the north and South) continuous wave records, this paper presents 9s, 15s and 20s of the Leibo Rui and Loew wave phase the velocity profile, and the distribution map was discussed. Short period (9S) Leibo Rui and Loew phase velocity distribution is similar, and has good correlation with the geological features, the two imaging results also confirm each other. Through the three-dimensional shear Analysis of wave velocity structure can be obtained as follows: the small earthquakes in Haicheng district and Tangshan District occurred in the shallow crust, and is located in the high and low transition zone and fracture extension direction of belt or fault zone; Bohai central and northern waters along the Tan Lu fault zone of lower crustal high velocity, high speed thin layer exists near the crust at the bottom of the Moho, the deep material along the Tanlu fault zone upwelling erosion of the earth's crust. Provide the basis for data processing on the Southern China area but also for homemade broadband seismograph for broadband array detection test and background noise image related data processing to do the groundwork. Imaging results provide seismic background noise the reference for the actual analysis of geothermal exploration work; inoculation analysis provides the basic phenomenon of earthquake occurrence and seismic tectonic background of earthquakes in the study area; special geological structure and characteristics The study of deep dynamic processes provides a reference.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P631.44

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