延庆、怀来地区地壳深部磁性构造与地震的研究

应用三维磁性层反演理论和方法，对延庆、怀来地区航磁资料进行了数据处理，反演计算了该区磁性基底埋深、居里等温面埋深和视磁化强度分布。揭示了延庆盆地、矾山盆地、怀来盆地、涿鹿盆地等四个相互联通盆地的磁性基底的定量特征。对该区地震发生的深部原因和地壳内不同特性块体与地震的关系进行了探讨；对该区地震分布的特点进行了研究；初步提出了该区地震的危险区划和今后的重点监测区。     

四川盆地及其西部边缘震区基底磁性界面与地震的研究

在对四川盆地及其西部边缘震区航磁资料进行分析研究的基础上，依据频率域磁性单界面反演方法对航磁异常进行了数据处理，求取了基底磁性界面的定量埋深，结合区域构造特征，地热分布及板块运动对地震的孕育环境进行了综合研究和讨论。     

利用航磁资料研究菏泽震区深部构造

利用航磁资料和三维磁性层反演理论,对菏泽震区的航磁资料进行了数据处理,计算出震区枧磁化强度分布图、基底磁性界面埋深图和居里等温面埋深图。结果显示东濮凹陷基底磁性界面深达12km,下部居里等温面上隆,凹陷内被弱磁性物质填充。地震发生在凹陷附近视磁化强度、基底磁性界面、居里等温面的变异带上。     

北京地区基底磁性界面反演及断裂研究

在对北京地区1∶10万航磁异常进行定性分析、小波多尺度分解及功率谱计算的基础上,运用三维磁性层反演方法,计算了北京地区基底磁性界面的定量埋深。根据反演结果对北京地区几条重要的基底断裂及其地震危险性进行了分析和探讨。     

基于改进型Tilt-depth法的磁源上顶与下底深度快速反演（英文）

Tilt-depth法可以用于快速反演磁源的上顶埋深,但其无法反演磁源底部深度,同时该方法的反演解过于单一。针对于此,本文在有限厚度台阶磁异常导数公式基础上,推导出了可以同时反演地质体上、下界面埋深的改进型Tilt-depth法计算公式,并采用在Tilt梯度图上选取多特征点进行联合反演的计算模式来提高反演解的可靠性。二维及三维组合模型试验均证实了改进型Tilt-depth法可以有效地反演出磁性体的上顶与下底深度,且上顶埋深的反演精度明显高于常规方法的。最后将改进型Tiltdepth法用于松辽盆地长岭断陷航磁数据反演,其上顶埋深的反演结果与钻孔钻遇火山岩的深度基本一致,证实改进型Tilt-depth法相对于常规方法的反演结果更加准确。     

中国内蒙古高原及周边地带岩石圈三维速度结构

我国内蒙古高原和其周边地域地壳与上地幔的专门研究尚属空白，然而全区又为第四纪以来的沙漠所覆盖，地表地质构造亦不十分清晰。本文利用了一种测量面波频散信号的新技术；即适配滤波频时分析和改进的分格随机反演理论与方法从混合路径中提取了４°×４°的计１８个网络中每一个网格单元的纯路径频散，并依据频散反演出该区地表与上地幔的剪切波三维速度结构。结果表明：１．该区地壳为成层结构，Ｍｏｈｏ界面埋深平均为３７±３ｋｍ，并向东减薄，断裂分布与构造迹线在深部均有显示，并存在着一系列北北东向，近北东向和北西向的断裂，且断抵上地幔顶部。２．上地幔亦为成层结构，地幔低速层平均埋深为８５±１０ｋｍ，南部地区则较深，地幔低速层速度均偏低。３．该区地幔盖层似一＂楔板，体向北插入。４．沙漠地带与造山地带相比不论是地壳厚度，还是地幔低速层埋深，前者均比后者浅约±５ｋｍ，该区有着良好的油气前景。     

用爆破地震研究湖南省深部构造与地震的关系

利用湖南省棋梓桥万罗山定向爆破观测资料,使用迭代法对棋梓桥至酃县剖面进行了二维构造反演,得到4层地壳结构模型:界面1埋深1.8—4km,v<6.0km/s;界面2埋深10.5—15km,6.0km/s相似文献   

四川盆地及其西部边缘震区居里等温面的研究

利用航磁资料和三维磁性层反演方法，对四川盆地及其西部边缘地区航磁异常进行了数据处理，求取了研究地区内居里等温面的定量埋深．以区域构造特征、地温梯度分布和人工地壳测深结果印证了反演结果的可靠性．通过深部地热场的分析讨论，论述了四川盆地西部边缘地区的地震，是在川青块体和康滇菱形块体与杨子板块碰撞作用下，产生了强烈的应力积累；又由于地幔热流的上涌，中、下地壳发生塑性蠕变，为岩石的裂错和应力的释放提供了调整单元深部环境下的孕育和发生．      

中国南北地震带磁性层构造特征

本文首先给出磁性层下界面反演的等效模型和其在球坐标系下变地磁倾角的二维反演方法,利用航磁资料研究了南北地震带的磁性层结构构造及其与地震活动性的关系为:1.磁性层南北两端厚,中间薄;2.下界面呈南北向的宽隆起带,北浅南深;3.磁性层所处的层位温压条件适于积累应力能量产生粘滑错动,地震多发生在磁性层内,往往位于磁性层由厚变薄的过渡处,并多伴有断裂、温泉、岩浆活动     

中国东南大陆及陆缘地带的瑞利波频散与剪切波三维速度结构

利用我国地震台站记录的瑞利波观测资料，通过适配滤波频时分析技术进行数据处理，获得了穿越我国东南及陆缘地区的瑞利波频散.使用随机反演理论取得了东南大陆及陆缘地带4°×4°网格的纯路径频散数据.在网格反演的基础上使用Harkrider的面波反演程序求得了该区剪切波的三维速度结构.结果表明：1.华南大陆Moho界面埋深为30-40km，并由西向东逐渐减薄，在陆缘与浅海地域为25-28km，具有明显的分区特征.2.上地幔低速层埋深为60-0km，变化幅度较大，这与深部断裂分布及深层过程有关，但NS向剖面上各界面的起伏变化均比EW向剖面平缓.3.东南陆缘是东亚大陆的海陆过渡带，在深部表现为Moho界面埋深和地壳平均速度降低的地带，地幔深部界面的起伏形态充分表明，深浅介质结构和物质耦合的不均匀性.     

1303年山西洪洞8级地震震源断层研究

1303年在山西洪洞附近发生的8级巨大地震, 是中国根据现存较为详细的文献记载史料所确定的最早的一次8级地震。 这次地震距今已有700多年的历史, 而地震所在区域至今仍有持续不断的小地震活动。 本文根据地震破裂区1981年至2013年的中小地震精定位地震目录, 采用震源断层面拟合方法, 反演得到了1303年山西洪洞地震的震源断层面参数: 走向19.3°、 倾角88.5°、 滑动角-170.0°。 断层面长75.5 km, 宽26.2 km, 深度为地下11.12 ～37.35 km。 将地震破裂区的地震精确定位资料以近东西向的洪洞断裂为界划分为地震北段和地震南段, 分段进行地震震源断层拟合, 反演得到洪洞地震北段震源断层面参数: 走向13.7°、 倾角76.6°、 滑动角-157.6°。 断层面长32.7 km, 宽21.7 km, 深度为地下11.97～32.86 km; 南段震源断层面参数: 走向20.3°、 倾角87.1°、 滑动角-154.6°。 断层面长45.9 km, 宽16.6 km, 深度为地下9.32 km～25.50 km。 无论是分段还是不分段, 反演得到的洪洞地震震源断层均是右倾的近直立断层, 属于右旋走向滑动性质。 分段计算得到的地震北段震源断层深度比南段更深, 将反演得到的震源断层与临汾盆地深部构造最新研究成果进行了分析对比, 北段震源断层深度及倾角大小与深地震剖面推测得到的深大断裂几乎相同。 震源断层在地表的投影与洪洞地震的高烈度区能够较好地对应。     

Improved tilt-depth method for fast estimation of top and bottom depths of magnetic bodies

The tilt-depth method can be used to make fast estimation of the top depth of magnetic bodies. However, it is unable to estimate bottom depths and its every inversion point only has a single solution. In order to resolve such weaknesses, this paper presents an improved tilt-depth method based on the magnetic anomaly expression of vertical contact with a finite depth extent, which can simultaneously estimate top and bottom depths of magnetic bodies. In addition, multiple characteristic points are selected on the tilt angle map for joint computation to improve reliability of inversion solutions. Two- and threedimensional model tests show that this improved tilt-depth method is effective in inverting buried depths of top and bottom bodies, and has a higher inversion precision for top depths than the conventional method. The improved method is then used to process aeromagnetic data over the Changling Fault Depression in the Songliao Basin, and inversion results of top depths are found to be more accurate for actual top depths of volcanic rocks in two nearby drilled wells than those using the conventional tilt-depth method.     

基于二阶导数的磁源边界与顶部深度快速反演

为实现磁异常反演,首先提出了磁异常非参数快速反演的概念,即无需提供先验信息.在Nabighian提出的磁场通用梯度公式的基础上,推导实现了基于磁异常垂向二阶导数的非参数快速反演(V2D_depth).它不仅可以获取场源的边界信息,同时可以反演场源的埋深.通过与Tilt_depth方法对比,本文方法计算的场源边界更清晰,反演的深度也更接近真实深度,同时较大程度上克服了Tilt_depth方法受叠加异常的影响.理论模型验证了方法的有效性,并通过准噶尔盆地某区块磁异常数据的处理,提取了受强大的区域背景场掩盖的石炭系火成岩产生的弱异常,突出了构造分区、断裂分布等信息,获取了火成岩的位置及埋深参数,为该区的火成岩油气藏勘探提供了有效的处理途径.     

磁化强度矢量反演方程及二维模型正反演研究

导了磁化强度矢量层析成像方程,并与磁化强度标量层析成像方程进行了对比. 使该矢量层析成像方程既适用于三维的也适用于二维,既适用于使用磁场垂直分量资料,也适用于使用磁场总强度资料. 本文采用改进的高斯-赛德尔迭代求解磁化强度矢量层析成像方程,在求解方程中引进了与深度有关的权系数. 并对二维模型开展了正反演研究. 当模型层数为二层,且每层51个柱体时,采用零初始模型就能获得较好的磁化强度垂直分量和水平分量反演结果,除了异常体边部外,磁化方向比较可靠. 当模型层数为五层,且每层51个柱体时,采用零初始模型不能得到较好结果,改用接近背景值的均匀初始模型,反演的磁化强度垂直分量和水平分量大致接近真实,但不能刻划某些细节.     

StudyofCurieisothermalsurfaceinSichuanBasinandtheseismicareaonitswesternmar┐gin

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Detecting small-scale targets by the 2D inversion of two-sided three-electrode data: application to an archaeological survey

The detecting capabilities of some electrical arrays for the estimation of position, size and depth of small-scale targets were examined in view of the results obtained from 2D inversions of apparent-resistivity data. The two-sided three-electrode apparent-resistivity data are obtained by the application of left- and right-hand pole–dipole arrays that also permit the computation of four-electrode and dipole–dipole apparent-resistivity values without actually measuring them. Synthetic apparent-resistivity data sets of the dipole–dipole, four-electrode and two-sided three-electrode arrays are calculated for models that simulate buried tombs. The results of two-dimensional inversions are compared with regard to the resolution in detecting the exact location, size and depth of the target, showing some advantage for the two-sided three-electrode array. A field application was carried out in the archaeological site known as Alaca Hoyuk, a religious temple area of the Hittite period. The two-dimensional inversion of the two-sided three-electrode apparent-resistivity data has led to locating a part of the city wall and a buried small room. The validity of the interpretation has been checked against the results of subsequent archaeological excavations.     

Gravity and magnetic data inversion for 3D topography of the Moho discontinuity in the northern Red Sea area, Egypt

The main goal of our study is to investigate 3D topography of the Moho boundary for the area of the northern Red Sea including Gulf of Suez and Gulf of Aqaba. For potential field data inversion we apply a new method of local corrections. The method is efficient and does not require trial-and-error forward modeling. To separate sources of gravity and magnetic field in depth, a method is suggested, based on upward and downward continuation. Both new methods are applied to isolate the contribution of the Moho interface to the total field and to find its 3D topography. At the first stage, we separate near-surface and deeper sources. According to the obtained field of shallow sources a model of the horizontal layer above the depth of 7 km is suggested, which includes a density interface between light sediments and crystalline basement. Its depressions and uplifts correspond to known geological structures. At the next stage, we isolate the effect of very deep sources (below 100 km) and sources outside the area of investigation. After subtracting this field from the total effect of deeper sources, we obtain the contribution of the Moho interface. We make inversion separately for the area of rifts (Red Sea, Gulf of Suez and Gulf of Aqaba) and for the rest of the area. In the rift area we look for the upper boundary of low-density, heated anomalous upper mantle. In the rest of the area the field is satisfied by means of topography for the interface between lower crust and normal upper mantle. Both algorithms are applied also to the magnetic field. The magnetic model of the Moho boundary is in agreement with the gravitational one.     

Depth and shape estimates from simultaneous inversion of magnetic fields and their gradient components using differential similarity transforms

The differential similarity transform of a magnetic anomaly is a linear combination of its intensity and gradient components. This transform is sensitive to the distance between a chosen central point of similarity and the source and depends on the degree of homogeneity of the field. Taking advantage of this property, a new field inversion method resulting in the evaluation of source position and shape type is proposed and implemented. The field gradient components are measured directly in magnetic gradiometry, or they can be calculated from the measured field data. Regional and local linear backgrounds are accounted for by the method. The method can be applied on either regularly or irregularly-spaced data sets, on even or uneven surfaces of observation. The solving of the systems of equations is not necessary. A semi-automated inversion for both location and shape of the sources is implemented. Model and field tests illustrate the effectiveness of the proposed inversion technique for depth and shape estimates.     

基于深度学习的重力异常与重力梯度异常联合反演

高效高精度的反演算法在重力大数据时代背景下显得尤为重要,受深度学习卓越的非线性映射能力的启发,本文提出了一种基于深度学习的重力异常及重力梯度异常的联合反演方法.文中首先提出了一种基于网格点几何格架的重力异常及重力梯度异常的空间域快速正演算法,这为本文深度学习反演算法的实现奠定了基础;其次对大量的不同密度模型进行正演计算获得样本数据集;然后设计了一种端到端的深度学习网络结构(GraInvNet),再利用样本数据对该网络结构进行训练;最后进行反演预测.组合模型试验表明,多维度数据联合反演相比单一分量反演其结果更“聚焦”,且与模型边界高度吻合,并且对于复杂模型的姿态与物性预测具有极为显著的优势,以及对于含噪声数据的反演,其质量也不会降低;Vinton岩丘实测重力数据也验证了文中方法的有效性;从而证明了深度学习在重力数据的高效高精度反演方面具有的巨大潜力.