小波变换与地震奇异性属性

地震属性是由地震数据提取的有关地震波的几何形态、运动学特征、动力学特征和统计学特征等组成。这里主要讨论了一种新的地震属性(奇异性属性)计算方法。由于地震数据携带着大量的奇异性信息,因此,这一新的地震属性是在偏移地震数据的小波变换和奇异性分析的基础上形成的。小波变换使检测数据中的局部奇异程度成为可能。为能够估计出偏移地震数据每一采样点的局部奇异规律,从小波变换系数的角度来提取地震信号的奇异指数。这种新属性实行单道处理,不需要子波和速度信息,它给出了地下分层情况和断层位置。在地震数据奇异性属性的基础上,用小波变换来划分地层旋回,从而提高了小波变换在地震解释中的应用。     

基于GIS的石河子市土地利用数据库的建立

基于地理信息系统建立土地利用数据库能为土地管理部门提供科学、快捷、有效的管理手段。在遵循国家有关标准对石河子市土地利用数据库系统进行了设计,以地理信息系统软件为工作平台,分别进行了数据处理、图形数据库的建立和属性数据库的建立等建库工作,再用特殊的程序把非空间数据和已数字化的点、线、面空间实体连接在一起,生成系统数据库。可以查询土地资源现状、统计变更成果,以及各种土地利用图、表的输出,使得石河子市土地资源的管理手段从原始的手工管理过渡到利用计算机技术的现代化管理阶段,真正实现办公自动化。     

三维地震在煤矿开采中覆岩离层探测的试验研究

以山东济宁二号煤矿地下开采的覆岩变形为例,采用三维地震技术手段,在数据振幅保真处理的基础上,通过地震属性分析方法对由于地下采矿活动导致的离层发育情况进行了试验研究。结果表明:综合运用三维地震常规解释和三维地震振幅斜度属性分析技术,可以初步揭示覆岩离层的形态:在三维地震常规解释中,对于新采空区产生的覆岩离层,砂泥岩的强波阻抗反射特征将遭到破坏,而老采空区会因覆岩离层的闭合仍具有强反射特征;在地震振幅斜度属性与频率属性解释中,覆岩离层将导致地震波形、频率存在严重的畸变区域,即使与新采空区相邻的老采空区,其覆岩离层也会有明显的反应。通过类比分析,推断该区的覆岩离层范围为工作面后方50~80m,延伸距离160~180m,离层发育的最大尺度1m左右,两个注浆孔证实了此次三维地震推测的离层发育区范围及岩移的准确性。     

Permeability and P-wave velocity change in granitic rocks under freeze–thaw cycles

An extensive experimental investigation of microstructural changes in granites under freeze–thaw cycles using permeability and P-wave velocity measurements is described. Two types of natural granite rocks are considered and tested under dry and saturated conditions. The specimens were subjected to 200 heating–cooling cycles (??20°C/?+?20°C); each cycle had a duration of 24 h. The results indicate that the ageing process decreases the permeability and the P-wave velocity. The reduction in P-wave velocity is likely to be due to microcrack development (material damage). In dry samples, the microcracks result from the repeated differential contraction–dilatation of the mineral components. In water-saturated samples, there is an additional effect of freezing and thawing of water in the porous network. The decrease in permeability in the dry samples is due to partial closure of existing microcracks. In water-saturated samples, there was no increase in the permeability. A physically acceptable explanation is that new microcracks are not necessarily connected with those that already exist. Therefore the physicochemical process resulting from water–rock interactions also affects the permeability. This phenomenon reduces fluid flow in the material.     

基于属性关系深度挖掘的试题知识点标注模型

在各类在线学习系统中,为了给学生提供优质的学习资源,一个基础性的任务是对大量未标注的试题进行知识点标注.已有标注方法通常基于人工专家标注或者采用传统机器学习方法.在实际应用中,这些方法普遍存在成本过高、标注精准度不足等局限.为此,本文提出了一种基于属性关系深度挖掘的试题知识点标注模型.首先,利用句法语义模型和结构语义模型分别从试题文本和试题图形中抽取试题的显性属性关系.然后,利用蒙特卡罗树搜索构建问题求解框架,挖掘试题的隐含属性关系.最后,结合学科知识图谱,将属性关系映射到知识图谱空间,生成试题知识点.实验结果表明,所提出的方法能够有效地进行试题知识点标注,将对学生认知诊断、个性化试题推荐等具有一定的实际应用价值.     

潞安矿区地震勘探资料精细解释分析

介绍近年来潞安矿区煤矿三维地震精细解释情况和解释方法。根据精细解释结果与原三维地震解释成果实例对比情况,说明三维地震精细解释的效果及必要性。随着煤矿开拓的进行,地震资料需要根据揭露情况进行方案的及时调整,及时的探采对比及实时解释将极大提高地震资料的解释精度及利用率,也有利于提高地震勘探解释人员的解释水平,为矿井生产提供高质量服务的同时,推动地震勘探的发展。     

Characteristics of gravity and magnetic fields and deep structural responses in the southern part of the Kyushu-Palau Ridge

The southern part of the Kyushu-Palau Ridge (KPR) is located at the conjunction of the West Philippine Basin, the Parece Vela Basin, the Palau Basin, and the Caroline Basin. This area has extremely complex structures and is critical for the research on the tectonic evolution of marginal seas in the Western Pacific Ocean. However, only few studies have been completed on the southern part, and the geophysical fields and deep structures in this part are not well understood. Given this, this study finely depicts the characteristics of the gravity and magnetic anomalies and extracts information on deep structures in the southern part of the KPR based on the gravity and magnetic data obtained from the 11th expedition of the deep-sea geological survey of the Western Pacific Ocean conducted by the Guangzhou Marine Geological Survey, China Geological Survey using the R/V Haiyangdizhi 6. Furthermore, with the data collected on the water depth, sediment thickness, and multichannel seismic transects as constraints, a 3D density model and Moho depths of the study area were obtained using 3D density inversion. The results are as follows. (1) The gravity and magnetic anomalies in the study area show distinct zoning and segmentation. In detail, the gravity and magnetic anomalies to the south of 11°N of the KPR transition from high-amplitude continuous linear positive anomalies into low-amplitude intermittent linear positive anomalies. In contrast, the gravity and magnetic anomalies to the north of 11°N of the KPR are discontinuous and show alternating positive and negative anomalies. These anomalies can be divided into four sections, of which the separation points correspond well to the locations of deep faults, thus, revealing different field-source attributes and tectonic genesis of the KPR. (2) The Moho depth in the basins in the study area is 6–12 km. The Moho depth in the southern part of KPR show segmentation. Specifically, the depth is 10–12 km to the north of 11°N, 12–14 km from 9.5°N to 11°N, 14–16 km from 8.5°N to 9.5°N, and 16–25 km in the Palau Islands. (3) The KPR is a remnant intra-oceanic arc with the oceanic-crust basement.which shows noticeably discontinuous from north to south in geological structure and is intersected by NEE-trending lithospheric-scale deep faults. With large and deep faults F3 and F1 (the Mindanao fault) as boundaries overall, the southern part of the KPR can be divided into three zones. In detail, the portion to the south of 8.5°N (F3) is a tectonically active zone, the KPR portion between 8.5°N and 11°N is a tectonically active transition zone, and the portion to the north of 11°N is a tectonically inactive zone. (4) The oceanic crust in the KPR is slightly thicker than that in the basins on both sides of the ridge, and it is inferred that the KPR formed from the thickening of the oceanic crust induced by the upwelling of deep magma in the process of rifting of remnant arcs during the Middle Oligocene. In addition, it is inferred that the thick oceanic crust under the Palau Islands is related to the constant upwelling of deep magma induced by the continuous northwestward subduction of the Caroline Plate toward the Palau Trench since the Late Oligocene. This study provides a scientific basis for systematically understanding the crustal attributes, deep structures, and evolution of the KPR.©2021 China Geology Editorial Office.     

Crustal structure and variation along the southern part of the Kyushu-Palau Ridge

As an interoceanic arc, the Kyushu-Palau Ridge（KPR） is an exceptional place to study the subduction process and related magmatism through its interior velocity structure. However, the crustal structure and its nature of the KPR,especially the southern part with limited seismic data, are still in mystery. In order to unveil the crustal structure of the southern part of the KPR, this study uses deep reflection/refraction seismic data recorded by 24 ocean bottom seismometers to reconstruct a detail...     

珊溪水库地震小震震源机制解特征研究

利用P波初动和直达P、S波最大速度振幅比联合求解小震震源机制的方法求出珊溪水库ML2.0以上地震的震源机制,得到了珊溪水库震源机制各参数时空特征如下:主压应力为SN向,主张应力为EW向,应力主要为水平应力,发震断层倾角较大且多为走滑断层。在个别4级左右地震前P轴方位都有偏离再恢复的现象。在北纬27.65°～27.69°间,P轴方位集中在0°±30°或者180°±30°,节面走向集中在45°±15°或者135°±15°。震源深度大于4km的地震倾角多集中在70°～90°度之间。     

雅克拉断凸东段侏罗系-白垩系地层超覆圈闭预测

雅克拉断凸东段位于库车坳陷前缘斜坡带,侏罗系—白垩系向南超覆于前中生界凸起基底之上,形成了一系列地层超覆圈闭.由于大部分侏罗系—白垩系上超尖灭体不同程度地与前中生界区域性不整合(T50)下伏的不同地层接触,地层超覆圈闭的有效性受控于下伏地层的致密程度.利用地震属性、钻井资料和三维地震剖面相结合的方法对T50区域不整合下伏地层的分布、岩性和封堵性进行了分析,按封堵性将它们分为3种类型:下寒武统玉尔吐斯组—震旦系泥岩、泥质白云岩为封堵性底板,元古宇变质岩、中上寒武统白云岩和石炭系砂泥岩为可能封堵性底板,具溶蚀特征的中上寒武统白云岩和元古宇变质岩为渗透性储层底板.通过二维正演地质模型分析佐证了这3类不同封堵性能地层的地震识别特征.综合分析认为Jse3旋回、Kse1旋回以及Jse1旋回在DG2井附近可形成可观的、有效的地层超覆圈闭.