【作者】 刘金兰；

【导师】 李庆春；

【作者基本信息】 长安大学 ， 地球探测与信息技术， 2008， 博士

【摘要】 山西断陷盆地是汾渭盆地的主体部分。该盆地是世界上著名的地震、地质灾害活动区之一,其中,最著名的地质灾害是地裂缝。地裂缝活动严重影响着城市建设及国民经济的发展,已成为目前该盆地影响面最广、破坏最严重的地质灾害。研究表明,地裂缝的形成和发展主要是受控于基底构造活动或隐伏活动断裂。因此,查明该盆地基底构造及活动断裂分布特征是解决地裂缝灾害的关键问题之一。目前,对上述面积性的区域构造的研究主要是利用重磁位场资料。鉴于此,本论文以国家自然科学基金重点项目——汾渭盆地地裂缝灾害成因机理与大陆动力学(项目编号:4053021)为依托,以位于山西省中部的山西断陷盆地为研究区域,以重磁位场新技术与山西断陷盆地构造识别划分为主要研究内容,以获取全区及上下深、浅区域构造信息(全区断裂分布特征、前寒武纪古构造特征、浅层断陷盆地基底构造及盆内活动断裂特征等)为主要目标,以重磁位场数据为主要原始资料,以提高位场资料处理精度和分辨率的新方法、新技术为主要手段,以深地震测深剖面和浅层地震剖面为约束,并结合钻井、地质、构造演化,对山西区域构造进行了深入的研究。取得的主要成果和结论如下:1、利用小波多分辨分析技术首次对山西重磁位场数据进行了分离阶数与异常源特征对应关系的试验研究,通过基于研究区实际的模型对比模拟,半定量得出了小波分解阶次与深、浅源构造信息的对应关系。与常规方法相比,小波多分辨分析技术不但能分离浅部构造信息,保留深部构造信息,而且能保留深部构造信息的细节特征和弱异常信息。将该技术应用于山西重磁位场数据处理,获得了高分辨率的反映莫霍面起伏变化的深部(区域)重力场资料和反映前寒武纪古构造特征的区域航磁场资料;获得了高质量的反映断陷盆地低密度沉积特征的浅部(局部)重力场资料。上述成果为山西断陷盆地深部、浅部区域构造信息的进一步研究提供了良好的基础。2、首次在国内研究了基于曲率属性的位场自动反演新技术,并且对该方法进行了创新性的技术改进,使其不仅具有更好的反演效果,而且具有分离不同埋深场源信息的功能。提出的三个主要技术措施为扩展自动搜索极大值法、多分辨率阈值法、扩展自动搜索极大值和多分辨率阈值组合法。研究表明:上述技术措施不仅使原有方法受噪声的影响降低到最小,使反演的解更连续,水平位置和埋深更准确,而且具有分离不同埋深场源信息的功能,为浅、中、深层场源的分离提供了另一种思路,丰富了位场资料处理技术和手段。3、将改进后的基于曲率属性的位场自动反演新技术应用于山西重力异常数据的反演,得到了不同深度层的深、浅断裂信息。利用提出的扩展自动搜索极大值和多分辨率阈值组合法,研究了不同阈值系数k对应的不同埋深断裂信息,得到了它们之间的半定量关系,且当阈值系数k =1.0时获得的山西断陷盆地内新生代断裂系与本论文中利用小波分解得到的浅部(局部)重力场特征和新编制的第四系或新生界构造图成果相吻合,有效反映了断陷盆地边缘大断裂和盆内界限性断裂。4、研究了位场场源边界识别新技术,如斜导数法、斜导数水平梯度法及theta图法。模型试验研究表明:上述技术具有弱信号提取功能,能得到更多的地质信息,进一步提高了解释的准确性和精度。将该技术应用于山西重力异常数据处理,获得了丰富的平面断裂信息;利用theta图法对航磁异常小波分解6阶近似进行了前寒武纪古构造边界的识别,结合地质、构造演化等重新划分了前寒武纪古构造单元。新划分的古构造单元是利用人工地震测深剖面资料加以佐证了的结果,与前人结果相比具有更高的分辨率和可信度。5、利用重新划分的前寒武纪古构造单元研究了磁性基底构造对盆地形成的影响,结合人工地震测深剖面资料、重磁识别的断裂系及盆地磁性地壳结构等信息研究了区域构造与地震活动的关系。研究结果表明断陷盆地的形成受磁性结晶基底的制约;地壳结构越复杂,地壳介质之间的力学强度差异越大,热水点年释放量越小,就越容易孕育和发生大的地震。6、利用浅层地震剖面、钻井等资料,并参考重磁划分的断裂系,新编制了山西四个断陷盆地的第四系构造图。利用新编制的第四系构造图并结合新生界构造图,研究了新生代断陷盆地基底构造分区及盆内活动断裂分布特征。新编制的第四系构造图提供了盆地内构造分区和活动断裂分布信息,该信息可用于解释地裂缝的分布与基底构造活动或隐伏活动断裂之间的关系,为浅地表地裂缝的评价研究提供了重要的基础资料。本论文以重磁位场新技术为主要手段,将地震、钻井、地质等要素最大限度的融合在一起,研究了山西区域构造特征,为依托项目提供了丰富的深部和浅部区域构造信息,这不仅对地裂缝的防灾减灾具有重要的实际意义,而且对该区区域构造、矿产资源勘探和评价研究具有重要意义。此外,本论文对重磁位场新技术的研究成果丰富了位场资料处理技术和手段,具有一定的学术价值和实际应用价值。更多还原

【Abstract】 Shanxi fault basin is the main part of the Fen-Wei basins, which is one of the famous seismic, geological disaster areas in the world. Ground fissure as the most serious geological disaster impacts on urban construction and the development of the national economy, and has become the most widely impact and serious geological disasters in Shanxi Province. Research result shows that the formation and development of the ground fissure is mainly controlled by the basement tectonic activity or buried active faults. Therefore, it is one of the key problems to investigate the basin basement tectonic and the distribution of active faults for solving the ground fissure disaster. In present condition, the research on this type of regional tectonic mainly depends on potential field data.In view of above, this thesis relies on the project of“Genetic mechanism of ground-fissure hazards & continental dynamics in Fen-Wei Basin”(Item No.4053021) supported by the National Natural Science Foundation of China, and takes Shanxi fault basin located in the central Shanxi Province as the research area. New technologies are investigated and developed for potential field processing and the tectonic recognition & division are researched for Shanxi fault basin. The main aim is to investigate the deep and shallow tectonic information throughout the region (the distribution of fracture features, the features of formation age paleo-tectonic zone, the characteristics of shallow fault basement tectonic and the features of active faults in the basin). The main raw data are gravity, magnetic potential field data. By means of new methods and technologies to improve the accuracy and the resolution of potential field data processing, binding with deep and shallow seismic sounding profiles, combined with drilling, geological, tectonic evolution, the regional tectonic of Shanxi are studied in-depth. The main research results and conclusions are as follows:1. The multi-resolution wavelet analysis technology is applied into the experimental research of Shanxi potential field data processing for the first time to our knowledge. In contrast to simulation the actual model of the study area data, a semi-quantitative relationship between the order properties of the wavelet decomposition and deep & shallow source structural information has been obtained. Compared with the conventional method, the multi-resolution wavelet analysis technology can not only separate the shallow tectonic information with deep tectonic information remained, but also preserve the details and weak anomalies characteristics of the deep tectonic. During potential field data processing of Shanxi, this technology provides high quality gravity field data information in the deep tectonic researching, which reflects the Moho ups and downs. This technology provides regional aeromagnetic field data formation of age paleo-tectonic zone and shallow (local) gravity field data during shallow basin research, which reflects low-density deposition characteristics of the basin. These results provide a firm basis for further investigations.2. The potential field automatically inversion technology based on the curvature attribute is studied for the first time at home, and innovative improvements are made to the method. After that, it has not only better inversion effect, but also the function of separation different depths field source information. The three main technical measures are as follows: the expanded automatic search maxima method, the multi-resolution threshold method, the combined method of expanded automatic search maxima method and multi-resolution threshold method. Experimental study from model shows that, we can minimize the impact of the noise for the original method, and the result of the inversion is more continuous, the horizontal position and bearing depth are more accurately. At the same time, it has the power distinct the tectonic information from different depths. This method not only enriches the ways of potential field automatically inversion, but also provides another idea for deep and shallow source separation when processing gravity and magnetic anomalies.3. Application the developed technology of potential field automatically inversion technology based on the curvature attribute into Shanxi gravity anomaly data processing, obtained deep and shallow fault information of different depths. Studied the different threshold coefficients k and their corresponding fault information, obtained their semi-quantitative relationship. When the threshold coefficients k =1.0, the obtained Cenozoic era fault system in Shanxi fault basin matches the shallow (local) gravity characteristics obtained by multi-resolution wavelet analysis ,and accesses to the results of the new establishment quaternary tectonic map or the cenozoic group tectonic map, which effective reflects the edge large faults and the limits of faults.4. Investigated new detection techniques of geologic boundaries using potential-field data, the new techniques including tilt derivative (TDR), total horizontal gradient of the TDR and theta map. Model experiment results indicate that the new detection technology is more effective and accurate than the traditional horizontal gradient one and can gather more geological information. Applying those new technologies to the Shanxi gravity anomaly data processing, a wealth of plane fracture information is obtained. Studied the precambrian palaeo-tectonic boundaries detection by using theta map methods to the wavelet decomposition 6-order approximation, combined the geological and the tectonic evolution, and redrawn the precambrian tectonic units. The new redrawn precambrian tectonic units are proved by artificial seismic profiles data. Compared with the previous results, it has much higher resolution and credibility.5. Investigated the magnetic basement tectonic impact to the basin formation by the redrawn Precambrian tectonic units, combined with the artificial seismic profiles data, Studied the relationship between regional tectonic and seismic activity by combining with artificial seismic profiles data, the fault system which detected by gravity and magnetic, and the magnetic crustal tectonic, etc. The results indicated that the formation of fault basin constrained by magnetic crystalline basement. The more complex of the crustal tectonic, the greater the difference mechanical strength between crust media, the smaller thermal water release less, the easier bred major earthquake.6. Mapped the new quaternary tectonic map of four fault basin based on the data of shallow seismic profiles, drilling, and the redrawn fault system divided by the potential data processing, etc. Studied the cenozoic basement tectonic division of the fault basin and the distribution of the active faults in the basement by the new quaternary tectonic map above and the cenozoic tectonic map. The new mapped quaternary tectonic map provides the information of the tectonic division and active fault distribution features. That information can be used to interpret the relationship between ground fissures and buried active faults, which provides important basic information for shallow ground fissures evaluation.The new technologies for potential field processing are investigated and developed as primary means in this thesis, integrated maximize elements of seismic, drilling, geologic, etc. The regional tectonic of Shanxi is researched which provides wealth information for the relying project. It has not only important value for ground fissure disaster prevention and mitigation, but also great significance for mineral resources exploration and evaluation. In addition, the developed new techniques provide new technologies and means for potential field data processing. The work of this thesis has certain academic value and social impact.更多还原