新疆呼图壁大容量气枪震源数据处理及初步应用研究
发布时间：2018-11-03 13:23
【摘要】：地震波是照亮地球内部的一盏明灯,利用地震波研究地球内部结构、状态、和演化是目前了解地球内部情况的最主要方法[1]。随着地震学的不断发展,人们不再满足于依靠天然地震被动的研究地球内部情况,而是更多的依靠人工震源向地下发射地震波,主动的对地球内部进行探测[2]。进行这样的主动震源探测是研究介质特性、断层结构、地震预测预报等方面的重要技术途径。大容量气枪震源具有能量大、低频成分丰富、传播距离远和环保高效等优点,是探测地球内部的理想主动震源[3-4]。本文简要介绍了新疆呼图壁气枪震源发射台的建设过程、信号激发、大容量气枪震源的震源特性、信号特征等,并利用新疆数字地震台网接收到的呼图壁气枪发射台激发的地震信号,采用叠加、互相关等方法,初步研究了大容量气枪震源的震相特征,信号衰减特征和走时变化特征。得到以下结论:(1)新疆呼图壁大容量气枪发射台激发的信号主要频率集中在2-6Hz,6条气枪一次同时激发产生的能量相当于一次ML0.9级天然地震产生的能量。通过对信号进行叠加,最远可在距离气枪震源380km处的台站,发现气枪信号。(2)对以气枪震源为中心,400km为半径范围内的台站接收到的气枪信号进行叠加,并以6km/s的速度对信号进行折合,从折合走时剖面上发现气枪震源激发的信号,在200km以外出现的Pn波,而且在传播距到达200km以上后,气枪震源与天然地震的走时趋于同步。(3)选取北天山地区8个台站,对接收到的气枪震源信号进行叠加,计算各个台站叠加后的气枪震源信号2-6Hz之间的P波和S波振幅谱的均方根,作为地震波传播至该台站的振幅值,并对振幅衰减特征进行拟合,得出北天山地区的Qp=464±70和Qs=653±46。(4)把各个台站经过反卷积计算去除了震源影响后的信号进行波形干涉,测量得到各个台站特定震相的走时变化。以STZ台数据为例,发现在2013年8月30日乌鲁木齐MS5.1地震前走时变化表现为上升趋势,经过一段平稳期后,走时变化呈现下降趋势。初步分析可能是由于地震前应力积累产生的裂隙,地震后应力释放裂隙还原造成的。在内陆地区应用大容量气枪震源对地壳介质变化进行监测,是地震学领域中的一项新的尝试,为今后地下介质动态观测和地下4D云图的绘制打下了基础。
[Abstract]:Seismic wave is a bright lamp that illuminates the earth's interior. Using seismic wave to study the structure, state and evolution of the earth's interior is the most important method to understand the earth's interior situation at present [1]. With the continuous development of seismology, people are no longer satisfied to rely on natural earthquakes passively to study the internal conditions of the earth, but more rely on artificial seismic sources to launch seismic waves into the ground, active exploration of the earth's interior [2]. Such active source detection is an important technical way to study the characteristics of medium, fault structure, earthquake prediction and prediction. The large capacity air gun source has the advantages of large energy, rich low frequency components, long propagation distance and environmental protection and high efficiency. It is an ideal active source for detecting the earth's interior [3-4]. This paper briefly introduces the construction process, signal excitation, source characteristics and signal characteristics of the Hutubi air gun source transmitter in Xinjiang. Using the seismic signals generated by the Hutubi air gun emitter received by the Xinjiang Digital Seismograph Network, the seismic phase characteristics, signal attenuation characteristics and travel time variation characteristics of the large capacity air gun source are preliminarily studied by means of superposition, cross-correlation and so on. The following conclusions are obtained: (1) the main frequency of the signal generated by the large capacity air gun emitter in Hutubi Xinjiang is mainly concentrated in the energy generated by the simultaneous excitation of two to six gas guns equal to the energy generated by a natural earthquake of magnitude ML0.9. By superposing the signals, the air gun signals can be found as far away from the air gun source as 380km. (2) the air gun signals received by the stations with the air gun source as the center and the 400km as the radius range are superimposed. The signal is converted at the velocity of 6km/s, and the signal generated by the air gun source is found on the profile of the commutative travel time, and the Pn wave appears outside the 200km, and after the propagation distance reaches above 200km, The travel time of the air gun source and the natural earthquake tend to synchronize. (3) eight stations in the North Tianshan region are selected to stack the received air gun source signals. The root mean square (RMS) of P wave and S wave amplitude spectrum between the air gun source signal 2-6Hz is calculated, which is used as the amplitude value of the seismic wave propagating to the station, and the attenuation characteristic of the amplitude is fitted. It is concluded that the Qp=464 卤70 and Qs=653 卤46. (4) the signal of each station is interfered by the signal after deconvolution calculation and the specific phase of each station is measured. Taking the data of STZ station as an example, it is found that the change of walking time shows an upward trend before the MS5.1 earthquake in Urumqi on August 30, 2013. After a period of steady period, the change of walking time shows a downward trend. The preliminary analysis may be caused by the crack caused by the accumulation of stress before the earthquake and the reduction of the fissure released by the stress after the earthquake. It is a new attempt in the field of seismology to monitor the crustal medium change by using large capacity air gun source in inland area, which lays a foundation for the dynamic observation of underground medium and the drawing of underground 4D cloud map in the future.
【学位授予单位】：中国地震局兰州地震研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.44
本文编号：2307914
[Abstract]:Seismic wave is a bright lamp that illuminates the earth's interior. Using seismic wave to study the structure, state and evolution of the earth's interior is the most important method to understand the earth's interior situation at present [1]. With the continuous development of seismology, people are no longer satisfied to rely on natural earthquakes passively to study the internal conditions of the earth, but more rely on artificial seismic sources to launch seismic waves into the ground, active exploration of the earth's interior [2]. Such active source detection is an important technical way to study the characteristics of medium, fault structure, earthquake prediction and prediction. The large capacity air gun source has the advantages of large energy, rich low frequency components, long propagation distance and environmental protection and high efficiency. It is an ideal active source for detecting the earth's interior [3-4]. This paper briefly introduces the construction process, signal excitation, source characteristics and signal characteristics of the Hutubi air gun source transmitter in Xinjiang. Using the seismic signals generated by the Hutubi air gun emitter received by the Xinjiang Digital Seismograph Network, the seismic phase characteristics, signal attenuation characteristics and travel time variation characteristics of the large capacity air gun source are preliminarily studied by means of superposition, cross-correlation and so on. The following conclusions are obtained: (1) the main frequency of the signal generated by the large capacity air gun emitter in Hutubi Xinjiang is mainly concentrated in the energy generated by the simultaneous excitation of two to six gas guns equal to the energy generated by a natural earthquake of magnitude ML0.9. By superposing the signals, the air gun signals can be found as far away from the air gun source as 380km. (2) the air gun signals received by the stations with the air gun source as the center and the 400km as the radius range are superimposed. The signal is converted at the velocity of 6km/s, and the signal generated by the air gun source is found on the profile of the commutative travel time, and the Pn wave appears outside the 200km, and after the propagation distance reaches above 200km, The travel time of the air gun source and the natural earthquake tend to synchronize. (3) eight stations in the North Tianshan region are selected to stack the received air gun source signals. The root mean square (RMS) of P wave and S wave amplitude spectrum between the air gun source signal 2-6Hz is calculated, which is used as the amplitude value of the seismic wave propagating to the station, and the attenuation characteristic of the amplitude is fitted. It is concluded that the Qp=464 卤70 and Qs=653 卤46. (4) the signal of each station is interfered by the signal after deconvolution calculation and the specific phase of each station is measured. Taking the data of STZ station as an example, it is found that the change of walking time shows an upward trend before the MS5.1 earthquake in Urumqi on August 30, 2013. After a period of steady period, the change of walking time shows a downward trend. The preliminary analysis may be caused by the crack caused by the accumulation of stress before the earthquake and the reduction of the fissure released by the stress after the earthquake. It is a new attempt in the field of seismology to monitor the crustal medium change by using large capacity air gun source in inland area, which lays a foundation for the dynamic observation of underground medium and the drawing of underground 4D cloud map in the future.
【学位授予单位】：中国地震局兰州地震研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.44
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