三种断层位移测量工具对比分析          下载免费PDF全文

王辽  谢虹  朱俊文  薛善余  张正模  张波 《地震工程学报》2023,(5):1133-1144

基于构造地貌对活动断层进行定量研究对理解断层活动习性及预测其将来的活动行为具有重要的意义。目前人们对断层位错的获取主要采取软件测量的方式,因此对断层位错测量工具的可靠性及应用性的分析至关重要。文章首先对3种常用的测量工具LaDicaoz、3D＿Fault＿Offsets与MCSST进行介绍;然后,基于无人机摄影航测获得的党河水库断裂高精度DEM以及无人机机载LiDAR获取的西秦岭北缘断裂黄香沟段高精度DEM,使用MCSST对党河水库断裂进行详细的陡坎垂直位错测量,利用LaDicaoz和3D＿Fault＿Offsets对黄香沟断裂进行精细的水平位错测量,并通过交叉检验方法对这3种测量工具的可靠性进行分析;最后,基于不同性质断裂位移的提取过程和结果,对这3款软件的自动化程度、使用难易程度及可重复性等特性进行综合对比分析,并总结3种工具的优势与不足。研究结果表明,LaDicaoz和3D＿Fault＿Offsets在水平位移提取方面具有较高精度和较好应用,MCSST在垂直位移提取及分析上应用较好,但3种工具的自动化程度皆存在不足,工具间的相互借鉴并将人工智能引入将成为进一步提高测量软件科学性与...  相似文献   

2017年8月8日九寨沟MS7.0地震前成都台地磁谐波振幅比异常分析     

何畅  廖晓峰  祁玉萍  邱桂兰  任越霞 《中国地震》2017,33(4):575-581

2017年8月8日四川省九寨沟县发生M_S7.0地震,成都地震基准台距此次地震震中约255km,震前该台地磁谐波振幅比出现趋势性异常。对成都台GM4磁通门磁力仪秒数据进行谐波振幅比计算,结果显示,谐波振幅比在九寨沟M_S7.0地震前表现出下降—转折—恢复上升的异常变化形态,地震发生在异常恢复期,同时,异常表现出由长周期向短周期迁移、SN向与EW向变化不同步的特征,芦山M_S7.0地震前成都台地磁谐波振幅比亦呈现了相似的异常变化特征。  相似文献   

Performance of Soil Cation Exchange Capacity Pedotransfer Function as Affected by the Inputs and Database Size          下载免费PDF全文

Habib Khodaverdiloo  Hamidreza Momtaz  Kaihua Liao 《洁净——土壤、空气、水》2018,46(3)

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基于高频高光谱近感观测量化风对蓝藻水华的影响     

杨华音  张运林  李娜  张毅博  孙晓  王玮佳 《湖泊科学》2023,35(6):1927-1938

全球气候变化显著影响湖泊理化环境和生态系统演化,对生态系统服务造成负面影响甚至引发生态系统灾变,其中风速下降可能促使富营养化湖泊蓝藻水华的暴发和水面漂浮集聚。以往由于较低的观测频次,往往很难精细量化风对蓝藻水华的影响。利用陆基高光谱近感观测技术,基于分钟小时尺度开展周年高频观测,通过对6—10月蓝藻生长期太湖表层水体叶绿素a浓度统计分析,量化蓝藻水华高频动态变化特征,确定蓝藻水华漂浮集聚的风速阈值。研究发现,随着风速的下降,水体表层叶绿素a浓度随之增加,蓝藻水华出现概率也随之增加。概率分析显示,当近地面风速小于2.5 m/s时,湖泊表层比较容易形成明显肉眼可见的蓝藻水华,藻华发生概率为55.1%。长时间持续的低风速容易诱发蓝藻水华形成和漂浮集聚,强风浪事件后低风速出现1～2天叶绿素a往往就能恢复以往较高水平,这为管理者有效防控蓝藻水华提供了新视角。长期气象观测显示,气候变化影响下太湖地区风速呈现显著下降趋势,增加了蓝藻竞争优势和发生概率,有助于其在表面漂浮集聚。在未来的气候变化情景下,如果风速继续呈现下降趋势,在营养盐条件不变情况下湖泊表层蓝藻水华发生概率可能还会上升,增加蓝藻水华防控...  相似文献   

Data‐Driven Approach for Analyzing Hydrogeology and Groundwater Quality Across Multiple Scales          下载免费PDF全文

Zachary K. Curtis  Shu‐Guang Li  Hua‐Sheng Liao  David Lusch 《Ground water》2018,56(3):377-398

Recent trends of assimilating water well records into statewide databases provide a new opportunity for evaluating spatial dynamics of groundwater quality and quantity. However, these datasets are scarcely rigorously analyzed to address larger scientific problems because they are of lower quality and massive. We develop an approach for utilizing well databases to analyze physical and geochemical aspects of groundwater systems, and apply it to a multiscale investigation of the sources and dynamics of chloride (Cl^?) in the near‐surface groundwater of the Lower Peninsula of Michigan. Nearly 500,000 static water levels (SWLs) were critically evaluated, extracted, and analyzed to delineate long‐term, average groundwater flow patterns using a nonstationary kriging technique at the basin‐scale (i.e., across the entire peninsula). Two regions identified as major basin‐scale discharge zones—the Michigan and Saginaw Lowlands—were further analyzed with regional‐ and local‐scale SWL models. Groundwater valleys (“discharge” zones) and mounds (“recharge” zones) were identified for all models, and the proportions of wells with elevated Cl^? concentrations in each zone were calculated, visualized, and compared. Concentrations in discharge zones, where groundwater is expected to flow primarily upwards, are consistently and significantly higher than those in recharge zones. A synoptic sampling campaign in the Michigan Lowlands revealed concentrations generally increase with depth, a trend noted in previous studies of the Saginaw Lowlands. These strong, consistent SWL and Cl^? distribution patterns across multiple scales suggest that a deep source (i.e., Michigan brines) is the primary cause for the elevated chloride concentrations observed in discharge areas across the peninsula.  相似文献   

Tidal Response Characteristics of the Well Water Level in the Sichuan-Yunnan Region     

Gong Haobo  Li Guangke  Liao Xin  Guo Weiying  Chen Min 《中国地震研究》2017,31(2):188-200

In this paper, the long time series data of the well water-level data of 12 wells in the Sichuan and Yunnan area is analyzed by the Baytap-G tidal analysis software, and well water level tidal response characteristic parameters (amplitude ratio and phase change) are extracted. We analyzed the features of the shape and stage change, and characteristic parameters of the tidal response of well water level before and after the earthquakes, which can provide a new method and approach to analyzing the response relationships between well water level and earth tide and barometric pressure. The results show that Luguhu Well and 9 other wells are affected by earth tides, and their well water level amplitude ratios and phases are relatively stable; the Nanxi Well and Dayao Well water level changes are affected by the barometric pressure combined with tide force, and their well water level amplitude ratios and phases are more discrete. The water level amplitude ratios and phases of Jiangyou Well, Luguhu Well and Dongchuan Well are significant to large earthquakes, and the relationship between seismic energy density and water level amplitude ratios and phases of M₂ wave of the three wells are presented.  相似文献   

地震前后井-含水层系统潮汐参数变化特征分析——以云南弥勒井为例     

钱建秀  刘春平  樊春燕  石云  廖欣 《中国地震》2019,35(1):169-181

本文对弥勒井2004～2016年井水位同震响应形态及地震前后井水位潮汐参数变化关系特征进行分析。结果表明,在弥勒井水流运动方向总体是以垂向流为主、径向流为辅的前提下,天然因素(地震)和人工因素(洗井、装置改造)均可改变含水层水流运动方向。当震前潮汐因子和相位差反向变化时,能量较大的地震可以改变其水流运动方向,使震后潮汐因子和相位差呈同向变化,水流运动方向由以垂向为主变为以径向为主;能量较小的地震只是改变其含水层渗透系数,没有改变其水流运动方向,震后仍以垂向流为主。当震前潮汐因子和相位差呈同向变化时,能量较大的地震发生可以使径向含水层渗透系数增大,水流运动方向不变,震后仍以径向为主。通过分析潮汐参数变化,可以进一步得知井-含水层径、垂向流渗透系数的变化,为进一步精确计算含水层参数提供了参考。  相似文献   

Effect of fracture fill on frequency‐dependent anisotropy of fractured porous rocks          下载免费PDF全文

Liyun Kong  Boris Gurevich  Yan Zhang  Yibo Wang 《Geophysical Prospecting》2017,65(6):1649-1661

In fractured reservoirs, seismic wave velocity and amplitude depend on frequency and incidence angle. Frequency dependence is believed to be principally caused by the wave‐induced flow of pore fluid at the mesoscopic scale. In recent years, two particular phenomena, i.e., patchy saturation and flow between fractures and pores, have been identified as significant mechanisms of wave‐induced flow. However, these two phenomena are studied separately. Recently, a unified model has been proposed for a porous rock with a set of aligned fractures, with pores and fractures filled with two different fluids. Existing models treat waves propagating perpendicular to the fractures. In this paper, we extend the model to all propagation angles by assuming that the flow direction is perpendicular to the layering plane and is independent of the loading direction. We first consider the limiting cases through poroelastic Backus averaging, and then we obtain the five complex and frequency‐dependent stiffness values of the equivalent transversely isotropic medium as a function of the frequency. The numerical results show that, when the bulk modulus of the fracture‐filling fluid is relatively large, the dispersion and attenuation of P‐waves are mainly caused by fractures, and the values decrease as angles increase, almost vanishing when the incidence angle is 90° (propagation parallel to the fracture plane). While the bulk modulus of fluid in fractures is much smaller than that of matrix pores, the attenuation due to the “partial saturation” mechanism makes the fluid flow from pores into fractures, which is almost independent of the incidence angle.  相似文献   

Fluid identification based on P-wave anisotropy dispersion gradient inversion for fractured reservoirs     

J. W. Zhang  H. D. Huang  B. H. Zhu  W. Liao 《Acta Geophysica》2017,65(5):1081-1093

Fluid identification in fractured reservoirs is a challenging issue and has drawn increasing attentions. As aligned fractures in subsurface formations can induce anisotropy, we must choose parameters independent with azimuths to characterize fractures and fluid effects such as anisotropy parameters for fractured reservoirs. Anisotropy is often frequency dependent due to wave-induced fluid flow between pores and fractures. This property is conducive for identifying fluid type using azimuthal seismic data in fractured reservoirs. Through the numerical simulation based on Chapman model, we choose the P-wave anisotropy parameter dispersion gradient (PADG) as the new fluid factor. PADG is dependent both on average fracture radius and fluid type but independent on azimuths. When the aligned fractures in the reservoir are meter-scaled, gas-bearing layer could be accurately identified using PADG attribute. The reflection coefficient formula for horizontal transverse isotropy media by Rüger is reformulated and simplified according to frequency and the target function for inverting PADG based on frequency-dependent amplitude versus azimuth is derived. A spectral decomposition method combining Orthogonal Matching Pursuit and Wigner–Ville distribution is used to prepare the frequency-division data. Through application to synthetic data and real seismic data, the results suggest that the method is useful for gas identification in reservoirs with meter-scaled fractures using high-qualified seismic data.  相似文献   

Development of a novel sacrificial-energy dissipation outrigger system for tall buildings     

Xinzheng Lu  Wenjie Liao  Yao Cui  Qing Jiang  Yaning Zhu 《地震工程与结构动力学》2019,48(15):1661-1677

The frame-core tube-outrigger structural system is widely used in tall buildings, in which outriggers coordinate the deformation between the core tube and the moment frame, leading to a larger structural lateral stiffness. Existing studies indicate that outriggers can be designed as “fuses” of tall buildings through dissipating seismic energy after yielding, to protect the main structure. To date, both conventional and buckling-restrained brace (BRB) outriggers have been applied in practice. Subjected to the maximum considered earthquake (MCE), the hardening effect of BRB outriggers increases the damage of other structural components. Meanwhile, conventional outriggers are difficult to repair, owing to the local buckling-induced severe deterioration and damage. To overcome these problems, this study proposes a novel sacrificial-energy dissipation outrigger (SEDO) to improve the seismic resilience of tall buildings. The chords of SEDO are made of high-strength steel and remain elastic. The inclined braces of the SEDO are composed of a sacrificial part and an energy-dissipating part. Therefore, the SEDO remains elastic under design-based earthquakes (DBEs) and dissipates inelastic energy under MCEs. Moreover, the detailing of this novel SEDO is proposed on the basis of experimental studies. The optimal strength ratio between the sacrificial part and the energy-dissipating part is determined in the range of 6:4 to 4:6 on the basis of nonlinear time history analyses (THAs) and parametric studies. Afterwards, the SEDOs are used in an actual tall building to verify their seismic performances through nonlinear THAs. The results indicate the proposed SEDO is able to protect other structural components and effectively improve the seismic resilience of tall buildings.  相似文献