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1.
断层衍射波及其应用   总被引:1,自引:0,他引:1       下载免费PDF全文
本文从衍射波的物理定义出发,简化了Trorey提出的断层上Kirchhoff-Helmholtz衍射方程的解法;计算了不同深度、不同测线方向下的断层衍射波理论地震图;计算了衍射波振幅谱与相位谱,给出了利用衍射波求断层位置的公式;得出了一些新的结论,通过人工地震测深与地震勘探的实例,对断层衍射波的特性有了更明确的认识。 本文的结果表明:断层衍射波发生在地球介质剧烈变化处;衍射点两侧的衍射波走时曲线呈双曲线状;波初动清晰且半周期小;其优势频率振幅谱与反射波的相同,在衍射波与反射波走时曲线相切处附近,记录图中出现衍射波最大振幅,且波反相;视断点与真实断点一般不重合。上述特点可能为判定衍射波并确定断层位置提供判据。  相似文献   

2.
本文提出了衍射波勘探方法资料处理流程的构思框架,并给出了以复杂结构为目标所做的物性结构成像、几何结构成像及迭代开关识别等研究结果.  相似文献   

3.
本文提出了衍射波勘探方法资料处理流程的构思框架,并给出了以复杂结构为目标所做的物性结构成像、几何结构成像及迭代开关识别等研究结果.  相似文献   

4.
多波浅层地震勘探中的断层识别   总被引:2,自引:0,他引:2  
从多波勘探角度较全面地叙述浅层地震勘探中断层识别的文献不多见, 本文根据实际工作资料, 以多波勘探思想为基础, 从走时曲线、波形特征、震相特征、速度结构等多方面探讨了断层了的识别方法。研究结果表明, 由于实际情况的复杂性, 综合利用上述方法, 不仅能识别断层, 还能对断层的性质作研究, 能够取得一定效果。  相似文献   

5.
对沈阳、抚顺两市活断层探测中,地震S波反射法的应用进行了分析与研究,认为S波方法有容易激发、抗纵波干扰能力强、力辨率高等特点,尤其适于城市活断层地震勘探。  相似文献   

6.
断层活动性的探测研究是城市防震减灾的基础性工作。为了查明郑州老鸦陈断层的位置、性质及其活动性,2006年底跨老鸦陈断层进行了高分辨率的浅层地震P波和S波探测,通过采用不同的地震波激发源、不同的观测系统参数相结合的工作方法,获得了沿剖面不同深度的地下细结构图像,揭示了老鸦陈断层的形态和特征。结果表明,老鸦陈断层为一条倾向NE、走向NW的正断层,该断层错断了新近系(N)以前的地层,在Q+N地层内部没有发现断层引起的地层错断现象  相似文献   

7.
本文提出一个模型,通过此模型得到土星千米波辐射源(Saturn's Kilometric Radiation Source)的分布.这个模型就是:磁层顶的开尔文-亥姆霍兹不稳定性(Kelvin-Helmholtz Instability)会导致阿尔芬波沿着弯曲的磁力线传播到土星极区附近,并在这个过程中使土星电离层附近(1Rs高度,Rs为土星半径)的粒子加速沉降,发生回旋不稳定性(Cyclotron Maser Instability),进而产生R-X模式辐射的非寻常波(Extraordinary wave).我们认为,极区发生回旋不稳定性的区域就是土星千米波辐射源的区域.本文求出了磁层顶附近开尔文-亥姆霍兹不稳定性发生在土星本地时(Saturn's Local Time)11 LT以前,得出了阿尔芬波沿磁力线传播到土星需要约38.3 min,求解出向阳面磁力线弯曲了约80°,最后得出土星千米波辐射源分布从黎明段的7~9 LT延伸到傍晚段的18 LT,并且黎明段分布的纬度比傍晚段低.  相似文献   

8.
采用超声地震模型、数学模型正演试验和矿井试验观测研究了1<kα<10范围非均质体散射波场中,衍射波和转换波的运动学和动力学特征.上述方法获得了一致的结果.研究中发现一种次生震源及次生波,其在今后地震勘探中可能有一定的应用价值.  相似文献   

9.
采用超声地震模型、数学模型正演试验和矿井试验观测研究了1<kα<10范围非均质体散射波场中,衍射波和转换波的运动学和动力学特征.上述方法获得了一致的结果.研究中发现一种次生震源及次生波,其在今后地震勘探中可能有一定的应用价值.  相似文献   

10.
横波技术在工程物探中的应用   总被引:3,自引:0,他引:3       下载免费PDF全文
概述了横波勘探的方法技术及应用范围,指出了横波勘探在工程地震和工程物探工作中的重要性,根据实际工作需要,对某些方法所存在的问题提出了改进措施。介绍了几种方法的应用实例,实际应用效果显示该方法是比较实用的。  相似文献   

11.
郯庐断裂带安徽段的展布及其新构造活动   总被引:9,自引:3,他引:9       下载免费PDF全文
本文以近年来野外考察资料为依据,论述郯庐断裂安徽段的展布及其新构造活动特征。通过比较研究,表明该段无论在结构构造还是在新构造活动性方面都明显不同于中段  相似文献   

12.
Beijing plain area has been always characterized by the tectonic subsidence movement since the Pliocene. Influenced and affected by the extensional tectonic environment, tensional normal faulting occurred on the buried NE-trending faults in this area, forming the "two uplifts and one sag" tectonic pattern. Since Quaternary, the Neocathaysian stress field caused the NW-directed tensional shear faulting, and two groups of active faults are developed. The NE-trending active faults include three major faults, namely, from west to east, the Huangzhuang-Gaoliying Fault, Shunyi Fault and Xiadian Fault. The NW-trending active faults include the Nankou-Sunke Fault, which strikes in the direction of NW320°~330°, with a total length of about 50km in the Beijing area. The northwestern segment of the fault dips SW, forming a NW-directed collapse zone, which controls the NW-directed Machikou Quaternary depression. The thickness of the Quaternary is more than 600 meters; the southeastern segment of the fault dips NE, with a small vertical throw between the two walls of the fault. Huangzhuang-Gaoliying Fault is a discontinuous buried active fault, a boundary line between the Beijing sag and Xishan tectonic uplift. In the Beijing area, it has a total length of 110km, striking NE, dipping SE, with a dip angle of about 50~80 degrees. It is a normal fault, with the maximum fault throw of more than 1 000m since the Tertiary. The fault was formed in the last phase of Yanshan movement and controls the Cretaceous, Paleogene, Neogene and Quaternary sediments.There are four holes drilled at the junction between Nankou-Sunhe Fault and Huangzhuang-Gaoliying Fault in Beijing area. The geographic coordinates of ZK17 is 40°5'51"N, 116°25'40"E, the hole depth is 416.6 meters. The geographic coordinates of ZK18 is 40°5'16"N, 116°25'32"E, the hole depth is 247.6 meters. The geographic coordinates of ZK19 is 40°5'32"N, 116°26'51"E, the hole depth is 500.9 meters. The geographic coordinates of ZK20 is 40°4'27"N, 116°26'30"E, the hole depth is 308.2 meters. The total number of paleomagnetism samples is 687, and 460 of them are selected for thermal demagnetization. Based on the magnetostratigraphic study and analysis on the characteristics of sedimentary rock assemblage and shallow dating data, Quaternary stratigraphic framework of drilling profiles is established. As the sedimentation rate of strata has a good response to the activity of the basin-controlling fault, we discussed the activity of target fault during the Quaternary by studying variations of deposition rate. The results show that the fault block in the junction between the Nankou-Sunhe Fault and the Huangzhuang-Gaoliying Fault is characteristic of obvious differential subsidence. The average deposition rate difference of fault-controlled stratum reflects the control of the neotectonic movement on the sediment distribution of different tectonic units. The activity of Nankou-Sunhe Fault shows the strong-weak alternating pattern from the early Pleistocene to Holocene. In the early Pleistocene the activity intensity of Huangzhuang-Gaoliying Fault is stronger than Nankou-Sunhe Fault. After the early Pleistocene the activity intensity of Nankou-Sunhe Fault is stronger than Huangzhuang-Gaoliying Fault. The activity of the two faults tends to consistent till the Holocene.  相似文献   

13.
新疆天山主要活断层的分段及其在地震区划中的运用   总被引:1,自引:0,他引:1  
对天山地区活动断裂不同地段的几何形态、运动方式、地震活动特征存在的差异进行了分析研究。提出了活断层分段的标准和几种用于活断层分段的地震活动性指标:给出了活断层分段的标志点特征,并对新疆天山地区13条活断层进行了分段,讨论了分段结果在地震区划潜在震源区划分及其地震活动性参数确定中的应用。结果表明:通过活断层分段使潜在震源区的划分更准确、恰当,使地震活动性参数的确定更能反映出地震活动的时空不均匀性。  相似文献   

14.
北京顺义-前门-良乡断裂探槽的微观分析及其启示   总被引:2,自引:2,他引:2       下载免费PDF全文
松散沉积物中的断层常常未留下明显的宏观形迹,单靠肉眼观测往往难以确定断层是否存在,即使判断出有断层亦常难以确定其活动性质和活动方式。大量资料表明,微观分析是探讨松散沉积物中断层和古地震事件的行之有效的方法。文中通过对采自顺义-前门-良乡断裂的顺义油库探槽样品的微观分析,探寻松散沉积物中宏观形迹不明断层的显微沉积学和显微构造标志,并据此判断是否伴随古地震事件。研究结果表明,松散沉积物中的断层在微观上表现为明显的滑移错动面、微破碎带、变形条带、泥质充填条带、黏土矿物集中和定向的带、铁质物集中的带以及碎屑颗粒集中和定向的带等。显微沉积学研究则表明,断层及其附近的地层中显微纹层常发生扰动现象,断层内样品碎屑颗粒粒度分布的粗尾段降低而细尾端增高,棱角状颗粒含量明显增加;扫描电镜分析表明这些碎屑颗粒有新的破裂产生,而分形研究获得了断层内样品较高的分维值(D约为2.5)。上述特征可以作为松散沉积物中宏观形迹不明断层的微观判断标志。此外,本研究还发现了与震击物的一些宏观标志,如球状体或枕状体、负荷构造、流体流、固体物质流以及有机物的悬浮等非常相似的微观特征。显然,它们可以作为判断古地震事件的微观标志。上述结果表明,微观分析是  相似文献   

15.
曲江断裂断面结构及地震地质意义   总被引:1,自引:0,他引:1  
本文在野外地质调查的基础上,从曲江断裂两盘的地层分布、产状变化、破碎带宽度的异常分布等方面对曲江断裂的断面结构进行了初步分析,认为曲江断裂上存在两个尺度较大的凹凸体。结合该断裂的右旋运动特点,对曲江断裂破碎带异常展宽段及串珠状小盆地的成因给予了解释,同时认为曲江断裂上三次7级以上强震的震中与凹凸体的位置明显相关。  相似文献   

16.
虽然关于一些重要参数值仍然存在显著的不确定性,地学家们一致认为断层分布遵从幂律标度关系。本文我们把这些标度关系和地震分布的幂律标度关系结合起来获得了区域板内地震复发间隔对断层长度的标度关系式,再对其进行局部校准进而得到某一具体小地方的地震危险估计方法。小断层(未跨越孕震层与断4层)的标度资料表明地震复发间隔和断层长度的负幂成比例变化。由于最近认识到了大震标度中参数的不确定性,对于大断层(跨越孕震层的断层),其地震复发间隔是和断层长度的负幂还是和正幂成比例变化的问题是不确定的,这个问题对地震危险估计是至关重要的。  相似文献   

17.
弹性波反射法在桩基检测中的理论与应用   总被引:1,自引:0,他引:1  
林建生 《华南地震》1994,14(1):48-55
根据波动理论探讨了弹性波在砼桩中的传播衰减规律及反射特征,提出了判断桩基质量的有关理论依据,并结合工程实例应用弹性波反射法讨论了时域、频域分析法的基本原理及存在问题.  相似文献   

18.
西秦岭北缘断裂带是青藏高原东北部一条左旋走滑为主的活动断裂带,其在黄香沟一段活动性较强,活动现象典型。对沿断裂带分布的地貌、地质体等晚第四纪位移量的研究表明,在黄香沟一带,断裂晚更新世晚期以来的水平位移量最大为40~60m;最小为6~8m,可能是一次滑动事件的特征位错量。断裂带上的位移具有分组特征,各组位移值之间具有6~8m的稳定增量。位移值的分组性和增量特征反映了该段断裂具有特征地震的活动特征,而7组位错值则反映了断裂7次特征活动事件。关于黄香沟一带与断裂相关的微地貌分析,也获得了大致相对应的事件次数。并由此初步推测,晚更新世晚期以来,该断裂带有过多次强烈活动,活动期次明显  相似文献   

19.
In this study, we described a 14km-long paleoearthquakes surface rupture across the salt flats of western Qaidam Basin, 10km south of the Xorkol segment of the central Altyn Tagh Fault, with satellite images interpretation and field investigation methods. The surface rupture strikes on average about N80°E sub-parallel to the main Altyn Tagh Fault, but is composed of several stepping segments with markedly different strike ranging from 68°N~87°E. The surface rupture is marked by pressure ridges, sub-fault strands, tension-gashes, pull-apart and faulted basins, likely caused by left-lateral strike-slip faulting. More than 30 pressure ridges can be distinguished with various rectangular, elliptical or elongated shapes. Most long axis of the ridges are oblique(90°N~140°E)to, but a few are nearly parallel to the surface rupture strike. The ridge sizes vary also, with heights from 1 to 15m, widths from several to 60m, and lengths from 10 to 100m. The overall size of these pressure ridges is similar to those found along the Altyn Tagh Fault, for instance, south of Pingding Shan or across Xorkol. Right-stepping 0.5~1m-deep gashes or sub-faults, with lengths from a few meters to several hundred meters, are distributed obliquely between ridges at an angle reaching 30°. The sub-faults are characterized with SE or NW facing 0.5~1m-high scarps. Several pull-apart and faulted basins are bounded by faults along the eastern part of the surface rupture. One large pull-apart basins are 6~7m deep and 400m wide. A faulted basin, 80m wide, 500m long and 3m deep, is bounded by 2 left-stepping left-lateral faults and 4 right-stepping normal faults. Two to three m-wide gashes are often seen on pressure ridges, and some ridges are left-laterally faulted and cut into several parts, probably owing to the occurrence of repetitive earthquakes. The OSL dating indicates that the most recent rupture might occur during Holocene.
Southwestwards the rupture trace disappears a few hundred meters north of a south dipping thrust scarp bounding uplifted and folded Plio-Quaternary sediments to the south. Thrust scarps can be followed southwestward for another 12km and suggest a connection with the south Pingding Shan Fault, a left-lateral splay of the main Altyn Tagh Fault. To the northeast the rupture trace progressively veers to the east and is seen cross-cutting the bajada south of Datonggou Nanshan and merging with active thrusts clearly outlined by south facing cumulative scarps across the fans. The geometry of this strike-slip fault trace and the clear young seismic geomorphology typifies the present and tectonically active link between left-lateral strike-slip faulting and thrusting along the eastern termination of the Altyn Tagh Fault, a process responsible for the growth of the Tibetan plateau at its northeastern margin. The discrete relation between thrusting and strike-slip faulting suggests discontinuous transfer of strain from strike-slip faulting to thrusting and thus stepwise northeastward slip-rate decrease along the Altyn Tagh Fault after each strike-slip/thrust junction.  相似文献   

20.
张裕明 《地震地质》1993,15(4):317-322
对能动断层进行调查,需要确定能动断层鉴定对象的选择原则以及在不同情况下鉴定技术的应用及其实例  相似文献   

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