GIS-based analysis of fault patterns in urban areas： A case study of Irkutsk city, Russia

The capabilities of GIS in modeling fault patterns are explored for Irkutsk city in East Siberia with implications for ground stability. The neotectonic structure of the area is visualized in three dimension （3D） taking into account fault dips, using the ArcGIS, GlobalMapper and Paradigm Geophysical packages. The study area is divided into blocks of different size classes according to the length-based ranks of the bounding faults, which are of five classes distinguished with the equal interval method. The blocks show different deformation patterns, with different densities and strikes of crossing and bounding faults. The data are statistically processed using GIS to estimate the deformation degrees of blocks in arbitrary units per square kilometer using the attributes of rank and crossing/bounding position of faults and the size of blocks. The deformation degrees are then compared with available estimates of ground stability measured as a score of points corresponding to destabilizing factors. Although the comparison generally confirms some linkage between the deformation degree of blocks and their ground stability, the correlation is intricate and ambiguous. In order to enhance the advantages of GIS in building and analyzing 3D models of fault patterns for estimating ground stability and mitigating geological hazards, it is expected in the future to proceed from the reported initial step of visualization to more advanced analysis.

Fault Pattern Recognition Based on Hidden Markov Model

Because performance parameters of gear have degradation,a method is proposed to recognize and analyze its faults using the hidden Markov model( HMM). In this method,firstly,the delayed correlation-envelope method is used to extract features from vibration signals. Then,HMMs are trained respectively using data under normal condition,gear root crack condition and gear root breaking condition. Further,the trained HMMs are used in pattern recognition and model assessment. Finally,the results from standard HMM and the proposed method are compared, which shows that the proposed methodology is feasible and effective.

Active Faulting Pattern,Present-day Tectonic Stress Field and Block Kinematics in the East Tibetan Plateau

This paper examines major active faults and the present-day tectonic stress field in the East Tibetan Plateau by integrating available data from published literature and proposes a block kinematics model of the region. It shows that the East Tibetan Plateau is dominated by strike-slip and reverse faulting stress regimes and that the maximum horizontal stress is roughly consistent with the contemporary velocity field, except for the west Qinling range where it parallels the striking of the major strike-slip faults. Active tectonics in the East Tibetan Plateau is characterized by three faulting systems. The left-slip Kunlun-Qinling faulting system combines the east Kunlun fault zone, sinistral oblique reverse faults along the Minshan range and two major NEE-striking faults cutting the west Qinling range, which accommodates eastward motion, at 10--14 mm/a, of the Chuan-Qing block. The left-slip Xianshuihe faulting system accommodated clockwise rotation of the Chuan-Dian block. The Longmenshan thrust faulting system forms the eastern margin of the East Tibetan Plateau and has been propagated to the SW of the Sichuan basin. Crustal shortening across the Longmenshan range seems low （2-4 mm/a） and absorbed only a small part of the eastward motion of the Chuan-Qing block. Most of this eastward motion has been transmitted to South China, which is moving SEE-ward at 7-9 mm/a. It is suggested from geophysical data interpretation that the crust and lithosphere of the East Tibetan Plateau is considerably thickened and theologically layered. The upper crust seems to be decoupled from the lower crust through a decollement zone at a depth of 15-20 kin, which involved the Longmenshan fault belt and propagated eastward to the SW of the Sichuan basin. The Wenchuan earthquake was just formed at the bifurcated point of this decollement system. A rheological boundary should exist beneath the Longmenshan fault belt where the lower crust of the East Tibetan Plateau and the lithospheric mantle of the Yangze block are juxtaposed.

Sandbox Modeling of the Fault-increment Pattern in Extensional Basins

Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins. Experimental results showed that the tectonic action mode of boundaries and the shape of major boundary faults control the formation and evolution of faults in extensional basins. In the process of extensional deformation, the increase in the number and length of faults was episodic, and every ＇episode＇ experienced three periods, strain-accumulation period, quick fault-increment period and strain-adjustment period. The more complex the shape of the boundary fault, the higher the strain increment each ＇episode＇ experienced. Different extensional modes resulted in different fault-increment patterns. The horizontal detachment extensional mode has the ＇linear＇ style of fault-increment pattern, while the extensional mode controlled by a listric fault has the ＇stepwise＇ style of fault-increment pattern, and the extensional mode controlled by a ramp-flat boundary fault has the ＇stepwise-linear＇ style of fault-increment pattern. These fault-increment patterns given above could provide a theoretical method of fault interpretation and fracture prediction in extensional basins.

Coseismic fault model of the 2017 M_(W)6.5 Jiuzhaigou earthquake and implications for the regional fault slip pattern

On August 8,2017,an M_(W)6.5 earthquake occurred in Jiuzhaigou County,Sichuan Province,China,on the eastern margin of the Qinghai-Tibet Plateau.This study investigates the coseismic deformation field and fault model with ascending and descending Sentinel-1 synthetic aperture radar(SAR)images,aftershock distribution,and elastic half-space dislocation model.The regional fault slip pattern is then quantita-tively examined using the boundary element method.The results show that the ascending and descending interferometric synthetic aperture radar(InSAR)coseismic deformation fields display an overall NNW-SSE trend,with more significant deformation on the southwest side of the fault.The coseismic fault geometry is divided into NW and SE sub-faults with strikes of 162.1°and 149.3°,respectively.The coseismic fault slip is dominated by a left-lateral strike-slip movement with an average rake of-2.31°,mainly occurring at a depth of 0-13.04 km with a shape of an approximately inverted triangle.The fault slip features two peak slip zones,with a maximum of 1.39 m.The total seismic moment is 6.34×10^(18) N·m(M_(W)6.47).The boundary element calculation quantitatively indicates that the regional fault slip pattern may be mainly attributable to the changing strike and dip.The strike changes from NNWeSSE to nearly NS direction,and the dip gradually decreases from the Jiuzhaigou earthquake fault in the north to the Huya fault in the south.With these characteristics,the Huya and the Jiuzhaigou earthquake faults form the eastern boundary of the Minshan uplift zone and accommodate the accumulated deformation.

Structural patterns of fault damage zones in carbonate rocks and their influences on petroleum accumulation in Tazhong Paleo-uplift, Tarim Basin, NW China

Based on the outcrop survey,3D seismic data interpretation,drilling data analysis,the structural patterns and distribution of fault damage zones in carbonate strata of Tazhong Paleo-uplift were established to reveal the oil and gas enrichment law in the fault damage zones.The following findings were reached:(1)Through the filed survey,the fault damage zone system consists of fault core,damage zone with branch fault and fracture network.Affected by the active nature of the major faults,the fault damage zones differ in planar pattern and scale along the major faults.(2)3D seismic profiles reveal that there are three types of fault damage zones in carbonate strata in Tazhong paleo-uplift,strike-slip fault damage zones,thrust fault damage zones and superimposed fault damage zones.Featuring3 flowers and 3 root belts in vertical,the strike-slip fault damage zone can be subdivided into linear type,oblique type,feather type and horsetail type in plane.Thrust fault damage zones can be further divided into fault anticline type,anticline type and slope type.As the superimposition result of the above two kinds of fault damage zones,superimposed fault damage zones appear in three patterns,intersect type,encompassment type and penetrating type.(3)Cores from wells and geochemical data show oil and gas may migrate along the major fault and laterally.The feather type in strike-slip fault system,fault anticline type in thrust fault damage zone and intersect type in superimposed fault damage zone are possible sites for high production and efficiency wells.

Fuzzy Condition Pattern Recognition and Fault Diagnosis for Spacecraft

This paper introduces concepts of symptom vector and fuzzy symptom vector forspacecraft condition recognition and fault diagnosis,defines an operator and suggests a fuzzy pat-tern recognition method of fault diagnosis for spacecraft.This method is verified by examples andresults are checked from an expert system.

基于融合知识迁移网络的变工况轴承故障模式识别

针对基于迁移学习的故障诊断方法无法充分利用目标域数据,并且要求运行条件平稳,提出了一种基于融合知识迁移网络的变工况轴承故障模式识别方法。将输入瞬时转速作为工况信息输入到稀疏自动编码器中,从而充分利用目标域信息,使操作信息不必只利用局部振动数据集,而可以将整个操作信息纳入模型进行训练,并且通过模型训练大大降低了学习过程中负迁移的风险。然后利用深度卷积神经网络从原始振动中提取特征,通过两种知识迁移模型的结合,建立了融合知识迁移模型。最后,在滚动轴承实验测试台上的实验结果验证了该方法能够在变工况条件下实现有效的故障识别。

新疆准噶尔盆地西北缘克拉玛依-乌尔禾断裂带推覆体上盘构造样式及影响因素

准噶尔盆地西北缘克拉玛依-乌尔禾断裂带(克-乌断裂带)及其周缘发现了大量的油气藏,尤其是推覆体上盘伴随着勘探程度及地质认识不断深化,已呈现出“百里油区”的态势。然而,受多期构造活动及断裂带内部复杂的岩性组合影响,石炭系内幕地层构造样式展现出多种类型及复杂的空间展布样式,因此需要对构造样式及成因进一步探讨。综合地震和钻井资料,结合区域构造格局,梳理了准噶尔盆地西北缘克-乌断裂带上盘构造变形特征与影响因素;根据构造样式与推覆体内的岩性组合类型,将克-乌断裂带推覆体上盘划分出南段、中段和北段3个变形单元;明确了上盘石炭系5期主要构造阶段,分段恢复了推覆体上盘构造演化期次及样式。综合上述研究,认为克-乌断裂带上、下盘原始岩性组合关系是造成上盘石炭系内幕地层原始形变差异的主要因素,上盘石炭系内幕地层岩性组合差异是造成原生构造保存的主要因素。上述因素共同造成了圈闭条件沿克-乌断裂带自南向北变化。该研究为克-乌断裂带上盘油气勘探提供指导,同时也为类似条件地区的油气勘探提供借鉴。

复杂构造变形区断控裂缝发育分布模式

天然裂缝是油气重要的储集空间和渗流通道。在复杂构造变形区,裂缝明显受断层影响控制,但其规律和模式尚不清晰。为此,本次研究以库车坳陷为例,通过现场地质观测、成像测井裂缝解译和理论分析,计算断控裂缝系数,揭示走滑断层、逆冲断层控制复杂构造变形区天然裂缝的规律,提出断控裂缝发育分布模式。结果表明:(1)逆冲断层对天然裂缝产状和发育程度均具有明显的控制作用,裂缝密度与距断层距离呈现负指数关系,距断层由近及远可以划分为断层强控制裂缝带、断层弱控制裂缝带和区域裂缝带。(2)走滑断层包括调节走滑断层和逆冲走滑断层。调节走滑断层与地层走向近垂直或大角度斜交,发育断层控制裂缝带,其受断层规模影响显著;逆冲走滑断层与地层走向近平行或者小角度斜交,天然裂缝主要局限于断层带内,沿断层走向断裂带宽度发生变化。(3)定义断控裂缝系数(K),即断层强控制裂缝带宽度与断层断距(滑距)的比值,通过分析,库车坳陷逆冲断层K值为1.50~1.80,走滑断层K值为0.125~0.150。研究成果对复杂构造变形区油气勘探开发具有理论和实践指导意义。

LARGE-SCALE STRAIN PATTERNS,GREAT EARTHQUAKE BREAKS,AND LATE PLEISTOCENE SLIP-RATE ALONG THE ALTYN TAGH FAULT (CHINA)

Fieldwork along several segments of the Altyn Tagh Fault,between 85 and 95°E,confirms that it ranks as one of the most active faults of Asia.In the East,near Aksay,the active fault trace offsets numerous stream channels,terrace risers and fans tens to hundreds of meters. 14 C dating of organic remains and charcoal within terrace gravels indicates that most of the terraces were emplaced after the beginning of the Holocene,implying a left\|slip rate of about 2cm/a.Large mole tracks attest to the occurrence of great earthquakes.Even larger mole tracks are found north of Lenghu,within the Altun Shan push\|up,a 6000 m high range in a restraining bend of the fault,now sliced by its most active strand.North of Huatougou,at the transition between another push\|up mountain and a recent pull\|apart basin,a spectacular sequence of five flat\|floored,hanging channels,beheaded by the fault from a unique source in the mountain,have been horizontally displaced by up to 1250m.Cosmogenic dating of the abandonment of these channels and of nearby offset terrace risers confirms the slip\|rate at Aksay.Several km to the west,pressure ridges exceeding 10m in height across a large young fan,imply the repeat of several great earthquakes in a relatively short time span.

渤海湾盆地南堡凹陷油源断裂特征与油气差异富集模式

渤海湾盆地南堡凹陷具有油气富集层系不均的特征,为了揭示断层对油气差异富集的控制作用,通过分析油源断层类型、活动性及输导能力,得到了研究区断-源、断-盖等配置关系,建立了深、浅层油气富集模式。结果表明:南堡凹陷发育Ⅰ、Ⅱ、Ⅲ共3类油源断层,它们分别断穿沙三段、沙一段和东三段烃源岩,各类油源断层的垂向输导能力与其活动速率密切相关,由于3类油源断层的供烃能力依次减小,油气沿Ⅰ类、Ⅱ类、Ⅲ类油源断层向东二段以上层系运移的最小活动速率依次增加;研究区油气在东二段上下层系的差异分布受油源断层活动速率和断层与东二段盖层的配置关系共同控制,断层对盖层的破坏程度控制了油气能否穿过盖层,而是否有油气沿断裂垂向运移至盖层之上则受控于被油源断层断穿的烃源岩的供烃能力及油源断层的活动强度。综合建立了“断-盖封堵”深层油气富集模式和“断-盖开启”浅层油气富集模式,合理解释了南堡凹陷各构造带油气纵向富集差异的内在原因。研究成果可为同类油藏的勘探工作提供理论依据及指导。

基于SDP和MCNN-LSTM的齿轮箱故障诊断方法

齿轮箱在长期使用过程中,不可避免地会产生齿轮故障和轴承故障,严重影响传动精度和设备运行安全。基于此,针对齿轮箱常见故障类型,研究多通道对称点图案(symmetrized dot pattern, SDP)数据处理方法,并利用最小能量误差法实现SDP关键参数的选取。结合多尺度卷积神经网络(multi-scale convolutional neural network, MCNN)的空间处理优势、长短时记忆网络(long short term memory, LSTM)的时间处理优势及其良好的抗噪性和鲁棒性,提出了一种基于SDP和MCNN-LSTM的齿轮箱故障诊断模型。同时利用东南大学齿轮箱数据集,验证了基于SDP和MCNN-LSTM的齿轮箱故障诊断方法对齿轮和轴承常见故障类型特征提取的有效性,并与现有其他故障诊断方法进行对比,结果表明了所提方法具有更高的精度。

胶西北金矿控矿断裂深部特征及对找矿的启示——来自地球物理探测的证据

[研究目的]胶东是全球著名的金成矿区,金矿床主要受断裂构造控制,该区尚有很多断裂是无矿的,以往对断裂的深部形态及赋矿断裂与无矿断裂的区别特征缺乏深入研究。[研究方法]本文通过在胶东西北部实施重、磁、电长剖面和穿越主要金矿集区的广域电磁剖面、反射地震剖面,揭示了断裂深部特征,为赋矿断裂和无矿断裂的识别提供了重要证据。[研究结果]地球物理探测表明,胶西北地区的断裂构造有陡倾角的深断裂、缓倾角的铲式断裂和陡倾角的小断裂,其中控矿的三山岛、焦家和招平断裂均是铲式断裂。结合对金矿床的研究发现,矿床主要赋存于缓倾角断裂中,矿体呈阶梯分布特征,陡倾角的深断裂中未见明显的金矿化蚀变,现今金矿床赋存的最大深度在5 km左右。[结论]综合分析认为,低角度拆离断层和连续性不好的高角度小断层有较好的物理圈闭条件,有利于矿化富集;而产状平直、陡倾的深断裂不具备物理圈闭的条件,不利于成矿。胶东型金矿的找矿方向应集中于缓倾角的铲式断裂及其派生、伴生的陡倾角小断裂附近。

塔里木盆地台盆区走滑断裂带多层叠加样式及石油地质意义

随着塔里木盆地油气勘探的不断深入,在台盆区古生界发现大规模走滑断裂系统,提出了一种新型断溶体油气藏。受塔里木盆地多期构造运动的影响,走滑断裂表现出多层结构,具有多期叠加活动特征。基于高品质三维地震资料、钻井资料及油气地质资料,对塔里木盆地大型走滑断裂的多层叠加特征及对油气的控制作用展开研究。研究结果表明:塔里木盆地台盆区走滑断裂带在古生界主要发育5个结构层,分别为下寒武统盐下构造层、中寒武统盐构造层、上寒武统—中奥陶统碳酸盐岩构造层、上奥陶统—石炭系碎屑岩构造层和二叠系岩浆岩构造层;受多期构造运动及走滑断裂带活动的影响,5层结构在空间上具有带状分布、垂向叠置、差异叠加的特征;断裂叠加类型多样,总体上可以分为连接型、叠接型、反转叠加型及反转改造型4种;走滑断裂带叠加方式影响了石油地质条件,可形成多层差异聚集油气藏,主要包括Ⅰ型油气藏(奥陶系碳酸盐岩油气藏)、Ⅱ型油气藏(奥陶系碳酸盐岩油气藏、志留系碎屑岩油气藏及二叠系岩浆岩油气藏)及Ⅲ型油气藏(寒武系盐下层白云岩油气藏)3种类型。

基于宽频带混合法的跨断层地震动模拟研究

跨断层区域地震动(跨断层工程结构所在极近断层区域的地震动,以下简称跨断层地震动)与近场地震动在空间上的分布规律存在显著差异,而跨断层地震动记录匮乏导致跨断层结构抗震研究难以开展。文中简要介绍了宽频带混合法模拟地震动的基本理论,并以则木河断层为工程背景进行跨断层地震动的模拟,系统研究了跨断层地震动的分布规律。结果表明,模拟的跨断层地震动符合断层滑动模式,并且存在显著的方向性效应、上盘效应和滑冲效应,总体上模拟的跨断层地震动强度符合一定的衰减规律,但受断层破裂的影响会导致不规律甚至反规律。同时,实际地表破裂位置与断层破裂大滑移区对跨断层地震动分布规律会造成较大的影响。通过宽频带混合法人工模拟的跨断层地震动时间序列能解决跨断层地震动实测记录不足的问题,为跨断层结构抗震研究提供有力支撑。

基于输出电压轨迹的三相逆变器开关管开路故障诊断

开关管开路故障会让功率变换器的输出电压与电流产生严重畸变,因而降低了变换器输出的电能质量。开路故障出现后其余功率开关器件的损耗可能增加,所以容易在电路中引发二次故障。文中提出一种针对三相逆变器开关管开路故障的故障诊断方法。故障类型与故障器件的辨识通过分析三相逆变器在αβ平面上的输出电压轨迹实现,仅需要测量滤波后的输出线电压。所提出的方法易于实现,可以诊断三相逆变器的所有开关管开路故障情况。最后,通过仿真和实验验证所提出方法的可行性和准确性。

不同含水率断层宏微观破裂与强度折减损伤

为探究深部地区断层花岗岩不同含水率的宏观与微观跨尺度性质,开展了轴压力学试验、扫描电镜(scanning electron microscope,SEM)试验和X射线衍射(X-ray diffraction,XRD)试验,分析其多尺度破裂与强度折减损伤关系。结果表明:无水状态下宏观以剪切破坏为主且破裂面平滑,而随着含水率提高,其破裂模式以张拉破坏为主,裂纹路径与主应力方向平行且整体松散;低含水率工况微观破裂为沿晶破裂,高含水率工况为沿晶破裂和穿晶破裂的复合型破坏;吸水中期峰值强度与弹性模量两指标衰减率为前期6倍,达到衰减幅度最大限并呈非线性指数下降,吸水后期两指标衰减率回弹至前期状态;劣化系数随含水率增长而降低,吸水前期水分子起润滑岩石内部矿物作用,中后期阶段水分子发生侵蚀软化导致强度大幅度折减。

基于光纤声发射的局部放电信号识别方法分析

局部放电(PD)是电气设备绝缘退化的主要原因,相较于传统的检测方法,光纤声发射检测技术具有不影响设备运行方式、抗电磁干扰能力强等优点。设计并制作了尖端放电、气泡放电、悬浮放电和沿面放电4种典型局部放电模型,搭建了基于光纤声发射的局部放电声发射信号采集试验平台,采集了梯度施加电压下的局部放电声发射信号并对其进行了参量统计分析,提出了将去噪后信号时频图作为卷积神经网络特征输入的识别模型。试验结果表明,该识别模型对于淹没在噪声中的微弱局部放电信号具有良好的识别效果,识别准确率可达98%。

穿越活动断层隧道铰接设防宽度估算方法研究

考虑穿越活动断层隧道错断后可能发生的“S”型、上凸型、下凹型3种位移模式,推导出了隧道节段转角模式,进而求得隧道铰接设防宽度的估算方法。对比分析了节段伸长和节段相对转角两种变形对铰接设防宽度的影响,认为铰接设防宽度主要取决于节段相对转角。进一步分析了错动量、断层宽度、节段长度、位移模式曲线、铰接材料等相关参数对铰接设防宽度的影响。分析结果表明:铰接设防宽度与断层错动量、节段长度呈正相关关系,与断层宽度呈负相关关系;同时计算了3种位移模式在断层宽度170 m、隧道直径13 m、错动量0.2 m、设防节段长度8 m时的铰接设防宽度,并对比了相同条件下其他铰接设防宽度计算方法的结果,其结果均相近。研究成果可为穿越活动断层隧道铰接抗错设计提供一定参考。