大尺度雁列断层粘滑运动数值模拟

通过ANSYS软件建立二维雁列断层模型,采用粘弹性力学参数,建立摩擦系数接触单元,模拟10万年时间大尺度雁列走滑断层活动（地震相关活动）,分析挤压条件下的断层活动特征,研究结果表明：①断层时空区域不同,所受应力也不同,接近贯通区域重合地区所受应力较大,粘滑运动剧烈,由贯通区域向断层两侧逐渐延伸,所受应力依次减小;②摩擦系数越小,地震发生频率越高,地震运动周期越短,则位错量相对较小,易发生震级较小地震;摩擦系数越大,地震发生频率越低,地震运动周期越长,则位错量相对较大,易发生震级较大地震;③给定的边界挤压速率越大,地震发生频率越高,地震运动周期越短,则位错量增大,易发生震级较大地震。     

Numerical study on transient harbor oscillations induced by successive solitary waves

Tsunamis are traveling waves which are characterized by long wavelengths and large amplitudes close to the shore. Due to the transformation of tsunamis, undular bores have been frequently observed in the coastal zone and can be viewed as a sequence of solitary waves with different wave heights and different separation distances among them. In this article, transient harbor oscillations induced by incident successive solitary waves are first investigated. The transient oscillations are simulated by a fully nonlinear Boussinesq model, FUNWAVE-TVD. The incident successive solitary waves include double solitary waves and triple solitary waves. This paper mainly focuses on the effects of different waveform parameters of the incident successive solitary waves on the relative wave energy distribution inside the harbor. These wave parameters include the incident wave height, the relative separation distance between adjacent crests, and the number of elementary solitary waves in the incident wave train. The relative separation distance between adjacent crests is defined as the ratio of the distance between adjacent crests in the incident wave train to the effective wavelength of the single solitary wave. Maximum oscillations inside the harbor excited by various incident waves are also discussed. For comparison, the transient oscillation excited by the single solitary wave is also considered. The harbor used in this paper is assumed to be long and narrow and has constant depth; the free surface movement inside the harbor is essentially one-dimensional. This study reveals that, for the given harbor and for the variation ranges of all the waveform parameters of the incident successive solitary waves studied in this paper, the larger incident wave heights and the smaller number of elementary solitary waves in the incident tsunami lead to a more uniform relative wave energy distribution inside the harbor. For the successive solitary waves, the larger relative separation distance between adjacent crests can cause more obvious fluctuations of the relative wave energy distribution over different resonant modes. When the wave height of the elementary solitary wave in the successive solitary waves equals to that of the single solitary wave and the relative separation distance between adjacent crests is equal to or greater than 0.6, the maximum oscillation inside the harbor induced by the successive solitary waves is almost identical to that excited by the single solitary wave.     

Ground roll attenuation based on an empirical curvelet transform

In the field of seismic exploration, ground roll seriously affects the deep effective reflections from subsurface deep structures. Traditional curvelet transform cannot provide an adaptive basis function to achieve a suboptimal denoised result. In this paper, we propose a method based on empirical curvelet transform (ECT) for ground roll attenuation. Unlike the traditional curvelet transform, this method not only decomposes seismic data into multiscale and multi-directional components, but also provides an adaptive filter bank according to frequency content of seismic data itself. So, ground roll can be separated by using this method. However, as the frequency of reflection and ground roll components are close, we apply singular value decomposition (SVD) in the curvelet domain to differentiate the ground roll and reflection better. Examples of synthetic and field seismic data reveal that the proposed method based ECT performs better than the traditional curvelet method in terms of the suppression of ground roll.     

Study and application of PS-wave pre-stack migration in HTI media and an anisotropic correction method

Anisotropy correction is necessary during the processing of converted PSwave seismic data to achieve accurate structural imaging, reservoir prediction, and fracture detection. To effectively eliminate the adverse effects of S-wave splitting and to improve PSwave imaging quality, we tested methods for pre-stack migration imaging and anisotropic correction of PS-wave data. We based this on the propagation rules of seismic waves in a horizontal transverse isotropy medium, which is a fractured medium model that reflects likely subsurface conditions in the field. We used the radial (R) and transverse (T) components of PS-wave data to separate the fast and slow S-wave components, after which their propagation moveout was effectively extracted. Meanwhile, corrections for the energies and propagation moveouts of the R and T components were implemented using mathematical rotation. The PS-wave imaging quality was distinctly improved, and we demonstrated the reliability of our methods through numerical simulations. Applying our methods to three-dimensional and three-component seismic field data from the Xinchang-Hexingchang region of the Western Sichuan Depression in China, we obtained high-quality seismic imaging with continuous reflection wave groups, distinct structural features, and specific stratigraphic contact relationships. This study provides an effective and reliable approach for data processing that will improve the exploration of complex, hidden lithologic gas reservoirs.     

设备所在楼层对设备-结构相互作用的影响

为了研究设备所在楼层位置对设备-结构相互作用的影响,以某高层钢框架为例,将设备分别放置于结构顶层和底层设计了2种设备-结构体系模型,然后利用ANSYS有限元分析软件对整体模型进行地震响应时程分析。分析结果表明:在El Centro波、Taft波和人工波作用下,当设备频率与结构基频调谐时,设备-结构相互作用会令结构动力响应减小而设备动力响应显著增大;设备-结构相互作用的大小与设备所在楼层密切相关:顶层设备与结构间的相互作用比底层更加剧烈,这与位于不同楼层的设备间等效质量以及底端输入激励频谱的差异有关。     

Elastic one-return boundary element method and hybrid elastic thin-slab propagator for strong-contrast media with sharp boundaries

In this paper, we developed the theory and algorithm of an elastic one-way boundary element method(BEM) and a corresponding hybrid elastic thin-slab propagator for earth media with sharp boundaries between strong contrast media. This approach can takes the advantage of accurate boundary condition of BEM and completely overcomes the weak contrast limitation of the perturbationtheory based one-way operator approach. The one-way BEM is a smooth boundary approximation, which avoids huge matrix operations in exact full BEM. In addition, the one-way BEM can model the primary-only transmitted and reflected waves and therefore is a valuable tool in elastic imaging and inversion. Through numerical tests for some simple models,we proved the validity and efficiency of the proposed method.     

浙江临安4.2级地震特征及烈度调查

2017年4月12日,浙江省杭州市临安市发生4.2级地震,地震震中附近的潜川镇、河桥镇震感强烈,於潜镇、太阳镇、湍口镇等震感较为明显。在对震区地质构造、震源机制解资料分析的基础上,开展了烈度调查,并绘制了地震烈度图。本次地震震中烈度为Ⅴ度,面积22.6km2,烈度圈长轴方向北东向,与马金-乌镇断层走向一致。     

相邻两井对大地震的不同水力响应模型研究——页岩影响分析

大地震引起了左家庄和宝坻(相距～50km)两井中截然不同的同震水位响应.我们用水位的气压和潮汐响应来分析解释此现象.结果表明,宝坻井的观测含水层中存在页岩,且此井受裂隙影响很大,储水效应较差.页岩的复杂裂隙或者各向异性可能会导致此井观测含水层处于半封闭状态,从而导致垂直向排水的发生.通过多方计算分析后,我们将这两口井划分为两种模型—1.水平流动模型;2.水平流动+垂直流动的混合流动模型.由于裂隙影响,宝坻井的观测含水层介质与外界的水力沟通性在震前就较强(震前渗透率就比较大),所以宝坻井观测含水层与外界的孔隙压差异较小,导致同震渗透率上升较小甚至没有变化,这些因素是导致该井同震水位变化幅度总是非常微小的原因.     

马达加斯加石墨矿地质特征及其成因分析

马达加斯加石墨矿资源丰富,找矿潜力大。对马达加斯加东部及西南部3个典型石墨矿床进行综合对比研究,发现其石墨矿成因类型为区域变质型,矿石工业类型以大鳞片晶质石墨为主,自然类型可分为片岩型、片麻岩型及变粒岩型,石墨矿赋矿地层为Graphite岩系。对含矿岩石进行主量元素分析,认为其原岩为富含有机质、富铝的砂质、粉砂质、泥质沉积碎屑岩;形成环境为活动大陆边缘区域和大陆岛弧区域。马达加斯加石墨矿床的形成均经历了多次变质作用,富含有机质岩石主要通过区域变质作用形成晶质石墨矿床,并在混合岩化及深层次韧性剪切作用下进一步富集成矿。     

中国古代牧业社会骨制品的初步考察:以新疆巴里坤石人子沟遗址为例

考古遗址出土骨制品的研究对于揭示古代社会的动物资源获取和利用、手工业生产、社会组织结构等问题具有重要意义.国内骨制品研究目前多集中在农业区域,这些研究为探讨新石器时代至青铜时代的动物使用及其与社会发展、早期国家形成的关系等问题作出了重要贡献.然而,针对牧业社会骨制品的考察十分缺乏.新疆哈密地区巴里坤草原分布有大量古代牧业文化遗址,石人子沟遗址(43°31′12.8″~43°34′28.9″N,93°13′44.8″~93°16′49.1″E)是其中一处青铜时代晚期至铁器时代早期的大型聚落.本文从动物考古学视角研究该遗址2006年至2011年发掘出土的426件骨制品.结果显示,石人子沟遗址骨制品的原料主要为以羊(Ovis aries/Capra hircus)、马(Equus caballus)为主的家养动物和以鹿(Cervidae)为主的野生动物,其中羊的比例最高(69.7%),鹿(13.8%)、马(2.3%)次之,这与中原地区青铜时代农业文化遗址的骨制品多以牛为原料的情况明显不同.羊在骨制品原料中占绝对多数且大量使用羊距骨制品的现象是对石人子沟遗址以牧业为主的生业经济方式的直接反映.石人子沟遗址不同类型骨制品的制作各具特点,但整体表现出"省时省力"的特点,即对使用部位细致打磨,对非使用部位仅做简单处理.与中原地区商周时期大型制骨作坊规范化、规模化、产业化的骨器生产不同,石人子沟遗址未见专门的制骨场所,骨制品生产的操作链条也并不完整.遗址的骨制品生产可能是以家庭为单元进行的,产品的专业化、精细化程度也相对较低.该研究填补了我国古代牧业文化遗址出土骨制品动物考古学专门研究的空白,为进一步探究我国古代不同区域、不同生业经济基础下的制骨手工业面貌提供了重要资料.