基于NDVI纹理的山东丘陵地区SPOT-5影像果园信息识别研究   总被引：3，自引：1，他引：2  

王大鹏  王周龙  李德一 《测绘科学》2007,32(1):126-127,121

胶东半岛是我国重要的水果生产基地,及时有效地获取果园信息,对指导当地水果生产具有重要意义。在遥感信息提取中,纹理特征是一种有效的辅助信息,但在原始影像中地形阴影对纹理特征有较大影响。本文提出了一种利用NDVI影像的纹理特征和光谱特征从SPOT-5影像自动识别果园信息的方法,消除了地形阴影的影响,取得了86.40%的识别精度。  相似文献   

通过断层气氢探测新郑-太康断裂的浅层位置     

马兴全  王志铄  孙杰  李涛  李源  蔡颖哲  夏修军  赵显刚 《震灾防御技术》2017,12(2):354-362

新郑-太康断裂隐伏于河南省东部平原下,是一条规模较大的北西向断裂带,曾于2010年发生太康4.7级地震,确定该断裂准确的浅层位置对防震减灾具有重要意义。根据深部石油勘探资料,应用德尔格X-am 7000型多气体检测仪,在新郑地区布置2条与断裂走向近垂直的地球化学测线进行土壤氢气浓度测试,结果发现解放路和马庄村-前宫村测线异常点位处氢气浓度分别为背景值的16-33倍和40-50倍。2条H₂浓度曲线同步解释出一条倾向变化、宽约150m的走滑断裂带,位置与石油勘探资料吻合良好。此次研究表明利用断层气氢探测隐伏断裂的浅层位置在该区具有较好的可行性。  相似文献   

Effect of irregular structural configuration on floor acceleration demand in hill‐side buildings          下载免费PDF全文

Mitesh Surana  Yogendra Singh  Dominik H. Lang 《地震工程与结构动力学》2018,47(10):2032-2054

A suite of reinforced‐concrete frame buildings located on hill sides, with 2 different structural configurations, viz step‐back and split‐foundation, are analyzed to study their floor response. Both step‐back and split‐foundation structural configurations lead to torsional effects in the direction across the slope due to the presence of shorter columns on the uphill side. Peak floor acceleration and floor response spectra are obtained at each storey's center of rigidity and at both its stiff and flexible edges. As reported in previous studies as well, it is observed that the floor response spectra are better correlated with the ground response spectrum. Therefore, the floor spectral amplification functions are obtained as the ratio of spectral ordinates at different floor levels to the one at the ground level. Peaks are observed in the spectral amplification functions corresponding to the first 2 modes in the upper portion of the hill‐side buildings, whereas a single peak corresponding to a specific kth mode of vibration is observed on the floors below the uppermost foundation level. Based on the numerical study for the step‐back and split‐foundation hill‐side buildings, simple floor spectral amplification functions are proposed and validated. The proposed spectral amplification functions take into account both the buildings' plan and elevation irregularities and can be used for seismic design of acceleration‐sensitive nonstructural components, given that the supporting structure's dynamic characteristics, torsional rotation, ground‐motion response spectrum, and location of the nonstructural components within the supporting structure are known, because current code models are actually not applicable to hill‐side buildings.  相似文献   

Analytic wave series solution of out-of-plane(SH) waves diffraction by an almost semi-circular shallow cylindrical hill          下载免费PDF全文

Chunyang Ji  Vincent Lee 《地震科学（英文版）》2018,31(3):154-165

A closed-form wave equation analytic solution of two-dimensional scattering and diffraction of outof-plane(SH) waves by an almost semi-circular shallow cylindrical hill on a flat, elastic and homogeneous half space is proposed by applying the discrete Fourier series expansions of sine and cosine functions. The semi-circular hill problem is discussed as a special case for the new formulated equation.Compared with the previous semi-circular cases solutions, the present method can give surface displacement amplitudes which agrees well with previous results. Although the proposed equation can only solve the problem of SH-waves diffracted by almost semi-circular shallow hills, the stress and displacement residual amplitudes are numerical insignificantly everywhere. Moreover, the influences of the depth-towidth ratio(a parameter defined in this paper to evaluate the shallowness of the topography of hills) on ground motions are presented and summarized. The limitations and errors of truncation from Graf's addition theorem and Fourier series equations in the present paper are also discussed.  相似文献   

冀中坳陷束鹿凹陷潜山不整合特征与油气运聚模式     

蔡川  邱楠生  刘念  李振明  王元杰  鱼占文  焦亚先 《地质学报》2020,94(3):888-904

本文从冀中坳陷束鹿凹陷潜山顶面不整合接触类型及分布规律、结构特征及输导类型出发,精细刻画了不整合面之下半风化岩石层的垂向岩溶分带特征。在此基础上对典型剖面烃源岩热演化、油气运移进行模拟,建立了研究区潜山油气的运聚模式。结果表明,束鹿凹陷潜山顶面不整合包括4种接触类型、5种结构模式,具有3种输导类型,其中斜坡区和洼槽区西部以侧向型为主,斜坡区局部构造高点与洼中隆为侧向+圈闭型,凸起区以侧向+垂向型为主。不整合面之下半风化岩石孔缝洞体系发育,垂向上可划分为表层岩溶带、垂直渗流带以及三个水平潜流带,具有多期岩溶旋回特征。潜山顶部发育的垂直渗流带是油气沿不整合面运移的主力输导层,而内幕发育的多期水平潜流带是油气向内幕运移的潜在通道。深、浅部烃源岩热演化的差异以及与薄层砾岩是否接触导致了斜坡区与洼中隆潜山油气充注的差异,形成了斜坡区晚期薄层砾岩高效中转、不整合侧向运移、水平潜流带向内幕输导、顺向断层向上输导、反向断层圈闭成藏的油气运聚模式。  相似文献   

云南武定县朱家坝尾矿库渗漏原因浅析     

周南  李卿  喻涌麒 《云南地质》2020,(1):118-124

位于云南省楚雄州武定县朱家坝新建尾矿库,在使用过程中,该尾矿库下游一泉水点出现尾矿粉渗漏污染,通过地质勘查,发现该尾矿库下伏昆阳群绿汁江组(Pt2lz)的白云岩基底,存在一隐伏断层,渗漏污染原因与该断层及其形成的岩溶裂隙有直接的关系。  相似文献   

隐伏正断层错动致地表破裂变形特征的研究     

齐剑峰  郝文拯  王晓明  张江伟 《震灾防御技术》2019,14(3):628-639

通过建立三维计算模型,对隐伏正断层在均匀错动、倾斜错动和翘倾错动方式下地表土体的应力路径、破裂和变形特征进行了研究。根据地表破裂临界值,分析了工程建设“避让带”的宽度和起始位置的变化特征。根据行业规范,提出工程建设“关注带”的确定方法,分析了“关注带”的宽度和起始位置的变化特征,得到以下主要结论:①在断层错动过程中,位于两侧的地表土体应力路径变化明显不同,下盘一侧和上盘一侧分别以三轴拉伸和三轴压缩为主;②地表强变形带与地表破裂带的分布并不一致,需要综合考虑等效塑性应变和总位移比2个指标来评价同震地表错动对建筑物的影响;③当隐伏断层错动的垂直位移达到3m时,工程建设“避让带”的宽度在10—90m范围内变化,受上覆土体厚度和断层倾角的影响最大,而工程建设“关注带”的宽度在150—400m范围内变化,受上覆土体的性质影响最大。  相似文献   

Seismic indicators of focused fluid flow and cross-evaporitic seepage in the Eastern Mediterranean     

《Marine and Petroleum Geology》2017

We present for the first time a synthesis of the evidence of focused fluid flow in the Eastern Mediterranean, providing an updated record that includes recent and past occurrences through the last ca. 6 My of evolution of the basin. We do this by adding the interpretation of a previously unpublished regional 2D seismic dataset to the existing occurrences of focused fluid flow reported in the literature. Our interpretation shows a high number (141) of focused fluid flow features, which span the stratigraphic interval from late Miocene to Recent. Of these features, (82) are at the seabed, and (59) are buried. The previous published record is more difficult to quantify, but in comparison shows an overwhelming majority of seabed features, with only rare examples of buried features.The spectrum of the buried and seabed features covers pockmarks, pipes, mud volcanoes, clastic intrusions and collapse structures. Clustering of the fluid flow features is observed at different times in specific areas, including the Nile Cone, and the Levant, Herodotus, Cyprus and Latakia basins. With the buried record, we are able to highlight the evolution of the leakage points through time. Focused fluid flow venting has been occurring since the onset of the Messinian Salinity Crisis and the start of basinwide deposition of evaporites. We focus in particular on seismic indicators of leakage through evaporites, and of sub-evaporitic source for fluids and remobilised sediments. We also discuss the role of the evaporites as a seal to ascending fluids, and in which circumstances they can be breached.Fluids (and associated remobilised sediments) are sourced from different intervals, from the sub- and supra-evaporitic section, and possibly within the evaporites. Only a minor proportion of the fluid flow features are certainly sourced from below the Messinian evaporites, and most of them are located in the Nile-Levant-Eratosthenes areas. The few examples of pathways that are able to cross thick, undeformed and well preserved evaporites are typically correlated to overpressure release and hydrofracturing. This confirms that the evaporites do act regionally as a very good seal as expected, while fluids are able to cross the evaporites only in their most extreme expression, i.e. in near-lithostathic overpressure conditions. This is confirmed by our observations made in the Eastern Mediterranean, where in the presence of relatively undisturbed evaporites, cross-evaporite vertical fluid pathways are only observed at the high end of the flux-pressure range, and involve sediment remobilisation. Maps combining these different elements can be used to detect areas potentially more prone to breaching.  相似文献   

汶川地震山脚震害特征及机理分析1   总被引：1，自引：0，他引：1  

王伟  刘必灯  刘欣  沈超  周正华 《震灾防御技术》2014,9(4):863-871

汶川地震和以往地震现场震害调查表明,局部场地地形对震害的影响明显,其中,山脚房屋震害程度明显低于山顶和水平地表土层场地.针对这一震害特征,本文以汶川主震的地形效应观测强震动记录和人工爆破山体地形地震动观测记录为基础,通过数据分析,结合动力集中质量中心差分有限元法进行数值模拟分析,进一步揭示了山脚房屋震害轻微的特征不仅与其所在场地条件良好有关,更与山脚所处山体底部的几何位置直接相关.  相似文献   

跨断层水泥管试验的有限元分析     

贾晓辉  刘爱文 《震灾防御技术》2014,9(2):192-200

在考虑管道的材料非线性和几何非线性、管土相互作用的非线性和管道接口非线性的基础上,建立了由管体梁单元、三向土弹簧单元和接口单元组成的埋地非连续管道在断层位移作用下的有限元模型,并以美国密歇根大学Junhee等(2010)所做的跨断层水泥管试验为原型进行了模拟分析。有限元结果给出的水泥管最终变形、接口转角、接口位移与实验结果基本一致,表明本文提出的跨断层埋地非连续管道抗震计算的有限元分析方法具有一定的合理性。有限元结果和试验结果都表明,在逆冲断层作用下,水泥管的破坏主要是因为在管道接口处的轴向压力和弯矩的耦合作用,在断层附近的管道接口承受了较大的转动和压缩位移。本文所提出的分析方法可推广到埋地非连续管道在其它永久地面变形作用下的有限元分析。  相似文献