Fault zone structures of northern and southern portions of the main central fault generated by the 2008 Wenchuan earthquake using fault zone trapped waves

The rupture process of the May 12,2008 MS8.0 Wenchuan earthquake was very complex. To study the rupture zones generated by this earthquake,four dense temporary seismic arrays across the two surface breaking traces of the main-shock were deployed in July and recorded a great amount of aftershocks. This paper focuses on the data interpretation of two arrays across the central main fault,the northern array line 1 and southern array line 3. The fault zone trapped waves recorded by the two arrays were used to study the structure of the central main fault and the difference between the northern and southern portions. The results show that the widths of the rupture zone are about 170?200 m and 200?230 m for northern and southern portions respectively. And the corresponding dip angles are 80° and 70°. The seismic velocity inside the fracture zone is about one half of the host rock. By comparison,the northern portion of the rupture zone is slightly narrower and steeper than the southern portion. Besides these differences,one more interesting and important difference is the positions of the rupture zone with respect to surface breaking traces. At the northern portion,the rupture zone is centered at the surface breaking trace,while at the southern portion it is not but is shifted to the northwest. This difference reflects the difference of rupture behaviors between two portions of the central main fault. The width of the rupture zone is smaller than that of M8.1 Kunlun earthquake though these two earthquakes have almost the same magnitudes. Multiple ruptures may be one factor to cause the narrower rupture zone.

Rock Damage Structure of the South Longmen-Shan Fault in the 2008 M8 Wenchuan Earthquake Viewed with Fault-Zone Trapped Waves and Scientific Drilling

这篇文章是从科学的钻考察结果，差错地区在南方朗曼掸人差错(LSF ) 套住波浪(FZTW ) 在四川在 2008 5 月 12 日 M8 Wenchuan 地震破裂了的地区，中国。立即在 mainshock 以后，二个 Wenchuan 差错科学的钻(WFSD ) 地上凿穿在 WFSD-1 和 WFSD-2 地点被钻约 400 m 和表面的 1 km 西方沿着 Yinxiu-Beichuan 差错(YBF ) 破裂，南方 LSF 地区的中间的差错海滨。二地上凿穿遇见了主管分别地在 589-m 和 1230-m 的深度沿着 YBF Wenchuan 地震滑倒。slip 伴有一个 100-200-m-wide 地区由差错凿，角砾岩，碎裂岩和破裂组成。近到 WFSD-1 地点，将近垂直与限制为 YBF 的挂的墙的高度折断的岩石的宽地区在 Wenchuan 地震以后在扎根的表面被发现的 190-m ∼4.3t-m 滑倒。一个稠密的线性地震数组在这个地点越过表面破裂被部署记录余震产生的 FZTW。在这个跨差错的数组和网络车站记录的 FZTW 的有限差别的模拟关上到 YBF 的观察和 3-D 证明一个不同低速度的地区在 seismogenic 深度沿着南方 LSF 由严重地损坏的岩石创作了。地区沿着主管是几百米宽的滑倒，在哪个以内地震速度被 ∼30-55% 在浅深度在 ∼200-m-wide 破裂核心地区从墙岩石速度并且与最大的速度减小减少。推断 FZTW 的几何学和在浅深度的南方 LSF 破裂地区的物理性质在 WFSD 地上凿穿与从 petrological 和核心和井木头的结构的分析的结果一般来说一致。我们作为在在 2008 M8 地震的动态破裂期间是一个故障地区解释这个显著低速度的地区。我们检验了类似的地震在 2008 mainshock 前后产生并且观察到在差错核心地区以内的地震速度被∼10%在 M8 mainshock 期间由于差错岩石的严重损坏减少的 FZTWS 科学的钻和产生突出的 FZTW 的余震的地点也沿着 YBF 显示破裂分叉并且 Anxian-Guangxian 差错( AGF )，在浅深度的二束南方 LSF 。在南方 LSF 的地震、岩石学、地质的学习的联合进一步导致理解在差错地区之间的关系由于它的波导沿着低速度的差错地区摇力量扎根的结构和破裂动力学，和扩大完成。

Fault-zone trapped waves at Muyu in Wenchuan earthquake region

Trapped waves in the Qingchuan fault zone were observed at Muyu near the northeastern end of the fractured zone of the Wenchuan Ms8.0 earthquake.The results indicate a fault-zone width of about 200 m and a great difference in physical property of the crust on different sides of the fault.The inferred location of crustal changes is consistent with land-form boundary on the surface.

Fault zone trapped waves at Longmenshan fault belt

Trapped waves in different sections of Longmenshan fault belt were observed,and the results show the difference between the northern and southern portions of this fault belt.Guanzhuang and Leigu surveying lines are located at the northern portion of the fault belt,and the result indicates that the width of the rupture zone underground in this area is about 160-180 m.The center position of rupture zone underground corresponds to the surface breaking trace,and is equally distributed at the edges of the two fault walls.However,Hongkou surveying line is located at the southern portion of the fault belt,and the result indicates that the width of the rupture zone underground in this area is about 180-200 m.The rupture zone underground is mainly distributed below fault scarp.The Wenchuan Ms8.0 earthquake and Lushan Ms7.0 earthquake both occurred at the Longmenshan fault belt.The results will provide information for the structure background of the two violent earthquakes.

Study on rupture zone of the M=8.1 Kunlun Mountain earthquake using fault-zone trapped waves

The observation of the fault-zone trapped waves was conducted using a seismic line with dense receivers across surface rupture zone of the M=8.1 Kunlun Mountain earthquake. The fault zone trapped waves were separated from seismograms by numerical filtering and spectral analyzing. The results show that: a) Both explosion and earthquake sources can excite fault-zone trapped waves, as long as they locate in or near the fault zone; b) Most energy of the fault-zone trapped waves concentrates in the fault zone and the amplitudes strongly decay with the distance from observation point to the fault zone; c) Dominant frequencies of the fault-zone trapped waves are related to the width of the fault zone and the velocity of the media in it. The wider the fault zone or the lower the velocity is, the lower the dominant frequencies are; d) For fault zone trapped waves, there exist dispersions; e) Based on the fault zone trapped waves observed in Kunlun Mountain Pass region, the width of the rupture plane is deduced to be about 300 m and is greater than that on the surface.

SEM Numerical Simulation of Vertical and Inclined Fault Zone Trapped Waves and Comparison of Their Wave Fields

Fault zone trapped waves( F ZTWs) m ainly travel along the fractured fault zone( F Z)which is of low velocity and high attenuation. FZTWs often carry significant information about a fault  s internal structure,so it is important to understand their wave field characteristics for FZ structure inversion. Most previous simulations are based on vertical faults,while in this paper we implement the FZTW simulations on vertical or inclined faults and compare their wave fields in both time and frequency domains. The results show that the existence of fault zone and inclined angle of fault can significantly influence the features of waves near faults. In amplitude,a fault zone can generate a larger amplitude of waves. The velocity contrast between two walls of fault may lead to amplification of amplitudes in the low velocity fault wall. In frequency,a fault zone tends to influence the waves in the low frequency range. In a pattern of particle polarization of FZTWs,it tends to be single direction for vertical faults but fork to multiple directions for inclined faults,which might provide a new way to study the fault zone with FZTWs. These conclusions may be valuable for FZ structure inversion,and will enhance the knowledge on near-fault strong ground motions.

Exploration of fault-zone trapped waves at Pingtong Town,in Wenchuan earthquake region

Pingtong 镇位于 Wenchuan 8 的折断的地区。0 地震，并且被地震严重损坏。我们的观察线在 NW-SE 方向越过折断的地区在一条地震探索沟被集中，并且长是大约 400 m。结果在地震的破裂的差错地区揭示套住的波浪，并且在在媒介之间的物理性质显示大差别在内并且在差错地区外面。套住的差错地区的占优势的频率飘动关于 3-4 Hz。波浪振幅在探索沟附近是更大的。在在这个地点的外壳中的差错地区的宽度被估计是 200 m。在一些记录，波形和 S 波浪的到达时间在沟的二个方面之间是相当不同的。变化的地方与边界与一致在表面高举。

Dyke Emplacement in the Narmada Rift Zone and Implications for the Evolution of Deccan Traps

Dykes are primarily extensional fractures that form perpendicular to the minimum principal compressive stress,which have been extensively studied in the world during the past decades for various reasons including

金湖凹陷基性岩捕获锆石年龄及其区域构造意义

郯庐断裂带的形成演化是中国东部中生代关键大地构造事件,该断裂带起源机制问题是了解华南与华北板块汇聚过程与方式的基本前提。本文利用郯庐断裂带东侧金湖凹陷内7个新生代基性岩样品394个点的LA-ICP-MS锆石U-Pb年代学数据,在分析岩浆活动时代基础上,利用捕获锆石年龄信息探讨了大别造山带的古生代演化及郯庐断裂带起源机制问题,为认识上述问题提供了一个全新的视角。研究表明,金湖凹陷的基性岩浆活动时代为古近纪早期(66.1~56.5 Ma),与围岩的沉积时代吻合;基性岩中的捕获锆石来自大别造山带,是印支期板块碰撞造山中楔入郯庐断裂带东侧华南板块的造山带物质,具有华南板块、北淮阳和华北板块的混杂岩石圈信息;捕获锆石中445 Ma(变质锆石)、290 Ma(岩浆锆石)及214 Ma(变质锆石)等峰值年龄信息指示古生代以来北淮阳构造带经历了与北秦岭构造带类似的弧—陆俯冲、碰撞历程,暗示秦岭造山带的二郎坪洋、商丹洋和勉略洋可延伸至大别造山带东端;年代学数据及构造分析支持郯庐断裂带起源于嵌入碰撞背景下的华南板片撕裂边界,其起源形式为陆—陆碰撞下的板块斜向汇聚边界。

中西非裂谷系富油凹陷石油地质特征与勘探方向

基于地震、钻井、烃源岩测试分析等资料,对中西非裂谷系主要盆地富油凹陷石油地质特征进行研究,并探讨未来油气勘探方向。研究表明:中非裂谷系发育下白垩统湖相优质烃源岩,西非裂谷系发育上白垩统陆源海相优质烃源岩,两类烃源岩为中西非裂谷系油气富集提供了物质基础。中西非裂谷系发育包括基岩在内的多套储集层,并存在下白垩统、上白垩统和古近系3套区域盖层。晚中生代以来,受中非剪切带右旋走滑作用等地球动力学因素的影响,中西非裂谷系不同方向的盆地在裂谷作用期次、区域盖层发育层段、圈闭类型及成藏模式等方面存在差异。其中,北东—南西向盆地主要保存了早白垩世一期裂谷层序,区域盖层位于下白垩统裂陷期地层内,形成反转背斜、花状构造及基岩潜山等圈闭类型,发育“源储一体、源内成藏”及“源上储下、源下成藏”两种成藏模式;北西—南东向盆地具有多期裂谷叠置特征,发育上白垩统和古近系区域盖层,形成披覆背斜、断背斜、反向断块等圈闭类型,以“源下储上、源上成藏”为主要成藏模式。多期叠置裂谷盆地的源内成藏组合、强反转盆地的源内岩性油藏及页岩油是中西非裂谷系盆地未来勘探的重要领域。

断层阴影区地震优势信号提取新技术及其在西湖TT区的应用

在复杂断块地区,地震成像受断层的影响,断层下盘同相轴出现“上拉”、“下拉”或者同相轴错断的现象,极大地影响了断层圈闭构造高点的确定以及圈闭幅度的准确判断。开展针对复杂断层的高精度速度建模和高精度成像技术被认为是解决断层阴影区成像的主要处理技术解决方案。立足于地震采集信号自身的属性信息,充分挖掘地震信号的潜力,提出广角反射的折射线性去噪技术、中低频有效信号提取技术和优势信号精细速度建模技术,在西湖TT区目标评价中取得了良好的效果,明显减低了断层阴影对目标构造形态的影响,提高了构造圈闭定位的准确性。应用结果表明:通过准确的PSDM速度模型结合断层阴影区优势信号的提取,获得更聚焦的反射能量,断层阴影区弱振幅区得到消除,有效改善了断裂阴影区的成像效果。

Genetic models of structural traps related to normal faults in the Putaohua Oilfield,Songliao Basin

The Putaohua Oilfi eld is a fault-prolifi c area and the faults have close relation with structural traps. The genetic models of the structural traps in the Putaohua Oilfi eld can be divided into two types: individual fault model and multi-fault interaction model. This is based on the description of displacement distribution of typical individual normal faults, the geometry of the footwall and hanging wall, and the analysis of the interaction between faults and the corresponding change in geometry when the faults grow. The individual fault model is that the displacement reaches a maximum at or near the center of fault and decreases toward the fault tips, so a half-graben is formed on the hanging wall of the fault and a half-anticline is formed on the footwall because of the isostatic process. The multi-fault interaction model is that during the growth of faults, they overlap and interact with each other, and accommodation zones are formed in the overlapping segments. The accommodation zones are favorable targets for hydrocarbon exploration, and the trap characteristics are dependent on the extent of overlap and occurrence of faults. The multi-fault interaction model can be subdivided into three types: synthetic accommodation zone, convergent accommodation zone and divergent accommodation zone. Hydrocarbon migration and accumulation models of each type have been developed. The hydrocarbon migration and accumulation models of the traps with different genetic models have their own characteristics in the different stages of fault growth.

Creation Conditions and Development Model for Lithologic and Stratigraphic Traps in the West Sag of the Beach Area,Liaohe Depression

At present the Eocene reservoir is the focus of exploration in the west sag of the beach area,Liaohe Depression,and lithologic and stratigraphic traps are the most important in the future work.The regional geological background indicated that lithologic and stratigraphic traps might be created in the study area. Studies on creation conditions and distribution pattern of lithologic and stratigraphic traps are

Prospects and Current Studies on the Fault Zone Seismic Waves

Deep structure and material properties of faults can be understood by observing and simulating the particular phase in a fault fracture zone. This paper reviews the development of fault-zone seismic waves in the seismological domain. The present research status of fault-zone head wave and trapped wave are summarized systematically. Based on recent progress in this field,the paper discusses the prospect on the utilization of seismic wave in fault structure research.

北部湾盆地海中凹陷成藏关键要素及成藏模式

海中凹陷经几十年勘探虽点上有发现,但因成藏关键要素不明勘探陷入了停滞。该文为寻求其勘探规模突破方向,在成凹、成烃研究的基础上,深化成藏关键要素研究,建立了海中凹陷成藏模式,指出了规模突破的勘探有利区带。研究认为:海中凹陷油气成藏关键要素是近生烃中心、圈源时空匹配佳、油气输导条件好、优质储层发育。北部陡坡带是各成藏关键要素匹配最佳区,是海中最有利的勘探区带。研究成果为寻求海中凹陷规模油气突破指明了方向。

采用控压释放技术处置地层圈闭效应

因井漏或者反推钻井液引起的圈闭压力给现场井控措施的制定带来较大困扰,而控压释放技术是应对钻井过程中地层圈闭效应的有效方法。在充分分析圈闭压力的特点及实钻情况的基础上,开展了圈闭压力控压释放技术的探索与实践,形成了圈闭压力控压释放配套技术,通过严格执行关井求压、控压释放、循环排污和节流降密度的工艺流程,让圈闭内流体按一定比例匀速进入井筒,逐步降低圈闭内压力,较好地解决了漏失地层形成的短期圈闭压力难题。川西南部YT1井的成功应用表明,采取合理的控压释放方法能够安全降低圈闭内压力,扩展钻井液密度窗口,在溢流与井漏的矛盾中找到压力平衡点,有利于井控安全。

渤海辽北地区走滑转换构造发育特征及其对圈闭样式的控制作用

基于渤海辽北地区钻井资料和三维地震资料精细解释,对走滑断裂发育特征开展精细研究,并进一步完成对走滑转换构造的宏观判识和精细刻画,总结走滑转换构造对圈闭样式的差异控制作用。研究结果表明:①辽北地区断裂体系整体表现出强烈的右旋走滑性质,在走滑断裂叠接带、弯曲、尾端等构造位置,因构造应力调整而发育大量走滑转换构造;②依据走滑转换带的力学性质划分为增压型和释压型2大类,每一大类依据断裂空间展布关系进一步细化为单支弯曲型和双支叠复型,其中,单支弯曲型表现为单条走滑断层平面呈现“S”型变形,双支叠复型则表现为右旋左阶或右旋右阶;③增压型和释压型走滑转换构造控制发育的圈闭类型分别以断背斜和断块构造圈闭为主,增压型走滑转换构造控制的圈闭相对于释压型具有更大的勘探潜力。该研究丰富了走滑转换构造体系,填补了辽北地区走滑转换构造研究的空白,对渤海海域郯庐走滑断裂带油气勘探具有一定的借鉴指导意义。

美国对华战略竞争的“新中间地带”陷阱

“新中间地带”正在成为中美战略博弈的新领域。西方关于中间地带的旧理论固守零和思维,无法解释中美“新中间地带”的特征。中美“新中间地带”是随着中美关系变化、尤其是美国逐步推升对华战略竞争而出现。在中美战略互动中,“新中间地带”具有自主性、多样性、多面性的特征,对中美两个大国均有依赖性。这意味着任何大国都不可能独霸“新中间地带”。拜登执政以来,美国政府施展一系列动作大力争取“新中间地带”,试图开辟对华战略竞争的“第二战场”,目的是将中国拖入更大范围的战略竞争之中。

航空发动机高温升燃烧室技术分析

随着先进军用航空发动机推重比要求的不断提高,主燃烧室向更高温升方向发展。本文基于高推重比航空发动机主燃烧室的主要特征与面临的技术挑战,综述了多旋流燃烧、中心分级燃烧、驻涡燃烧和可变几何燃烧等四类高温升燃烧组织的工作原理和发展现状,分析它们的技术优势及挑战。就当前高油气比燃烧室来说,多旋流燃烧与中心分级燃烧是主要发展方向,但随着燃烧室油气比的持续提高,燃烧组织技术将面临更大技术挑战。通过综合分析,作者提出同心圆分区燃烧也可能是一种值得研究的适合更高油气比燃烧室的优选燃烧组织模式。

涠西南二号断裂带构造特征及其对成藏的影响

涠西南二号走滑断裂带及其周缘岩性圈闭是近年来勘探的热点,开展走滑断裂带形成演化及其对油气成藏的控制作用研究对下步勘探具有重要指导意义。利用最新的地震、钻井资料,对二号断裂带进行了系统综合研究。研究表明二号走滑断裂带西段、中段、东段活动具有明显的差异性,其中中段走滑活动最为强烈,走滑特征明显,西段和东段相对较弱。二号走滑断裂带差异活动控制着流沙港组一段(流一段)上层序、涠洲组三段(涠三段)古地貌的形成,从而影响沉积体系展布,进而控制岩性圈闭的发育。流一段上层序沉积时期,二号断裂带中段走向斜坡及其对应的沟槽位置是岩性圈闭发育的有利区,涠三段沉积时期,辫状河三角洲主河道与二号雁列断裂耦合区是构造+岩性圈闭发育的有利区。走滑断裂带主干断层和派生的次级调节断层是油气运移输导的重要通道,对油气成藏具有重要意义。走滑断裂对流一段上层序、涠三段油气的分布具有明显的控制作用。