Probabilistic modeling of seismically triggered landslides using Monte Carlo simulations

The 2004 Chuetsu earthquakes of Niigata (Japan) triggered numerous landslides, and the most widespread types of landslides were highly disrupted, relatively shallow slides and soil (debris) flows. This paper presented a method to evaluate slope instability using Newmark displacement on a pixel-by-pixel basis in a given area. The proposed method was able to integrate Newmark displacement modeling and Monte Carlo simulations within geographical information systems. In the modeling, an empirical attenuation relationship was utilized to calculate Arias intensity over this study area, and the variability of geotechnical parameters was taken into account to calculate coseismic landslide displacement. Before deriving the displacement from related inputs, the Monte Carlo simulations ran 1,500 times and generated 1,500 displacement values for each grid cell, and then means and standard deviations of displacement were calculated and probabilistic distributions can be obtained. Finally, given 10 cm as a threshold value of displacement, estimated probabilities of displacement exceeding 10 cm were shown as a map of seismic landslide hazards. The resulting hazard map was classified into four categories from very low to high level.     

Slope inclinometers for landslides

Slope inclinometers/indicators are used to determine the magnitude, rate, direction, depth, and type of landslide movement. This information is usually vitally important for understanding the cause, behavior, and remediation of a landslide. However, many inclinometer measurements fail to achieve these intended aims because of lack of appreciation of the many factors that need to be correctly implemented during installation, monitoring, and data reduction to yield useful data. This paper presents some guidelines for understanding, installing, and interpreting slope inclinometers and presents three case histories that illustrate some of the pitfalls that can develop if these guidelines are not followed.     

Rock magnetic record of Cenozoic lake sediments from the Linxia basin and aridification of the Asian inland

High resolution research of rock magnetic records and quartz sands from the Maogou Section in the Linxia basin reveals that after a relatively stable environment between 13.07 Ma and 8.6 Ma, the basin was gradually influxed by eolian dusts at about 8.6 Ma, with two rapid increases at about 6.4 Ma and 5.3 Ma, respectively. The study suggests that drying of northwest China began at 8.6 Ma and strengthened rapidly at about 6.4 Ma and 5.3 Ma. __________ Translated from Marine geology & Quaternary geology, 2007, 27(4): 103–110 [译自: 海洋地质与第四纪地质]     

Spatial distribution features and environment effect of heavy metal in intertidal surface sediments of Guanhe estuary, Northern Jiangsu Province

In northern Jiangsu coastal zone area, Guanhe River is the biggest river and has the best navigation conditions among rivers which flow into the Yellow Sea. The grain sizes show gradual increase from the high intertidal zone to lower intertidal zone. The heavy metal values have slight changes along both sides of the river mouth, but show an evident change perpendicular to the tidal flat. In the latter case, they show a good correlation with grain size fluctuation, that is, the heavy metal values gradually decline when the grain size increases from the high intertidal zone to the lower intra-tidal zone. Analyses of the heavy metal elements show that on the Guanhe estuary surface sediment, the content of the elements Hg, As and Cu is above background values; Pb and Zn contents are rather close to the background values; and Cd content is less than the background values. The element Hg comes out to be harmful in a medium level to ecological environment, while the elements of Cr, As, Cu, Pb, Zn and Cd fall in a safe range of MPL. On the whole, Guanhe estuary tidal flat is not very harmful to the ecology in terms of the heavy metals. __________ Translated from Marine Geology & Quaternary Geology, 2007, 27(5): 23–32 [译自: 海洋地质与第四纪地质]     

中国海相探矿权区块定量评价方法

在研究了我国海相油气探矿权区块基本油气地质条件、勘探程度、技术经济条件等要素和特点的基础上,给出了48个评价参数和归一化取值参照表,建立了探矿权区块评价工作流程、评分参数及计算公式。提出对我国海相勘探层探矿权区块评价应该注意:与国外海相碳酸盐岩评价的差别;与国内陆相碎屑岩评价的差别;成藏组合的划分;评价内容的有效性、不确定性和评价参数的可信度;成败经验的总结和勘探程度的研究。     

新鲜煤和氧化煤自燃倾向性的FTIR对比分析

利用傅立叶变换红外光谱（FTIR）分析技术,对乌达矿区低温氧化和新鲜煤样进行了红外光谱测试,通过两类煤样的特征官能团吸光度的对比分析．揭示了煤在氧化前后特征官能团的变化规律：氧化后的煤样中脂肪族和芳烃CH减少,酸酐C=O从无到有,芳烃骨架C=C基本不变,进而研究了其对煤自燃倾向性的影响。结果表明脂肪族和羟基含量越高,煤自燃倾向性越大。     

浅析旅游地图的网络化发展

旅游地图是人们旅行和导购导游的常用工具,对各地旅游业的发展具有十分重要的推动作用。本文论述了网络化旅游地图发行方式上所具有的优势,分析了当前旅游地图网络化的发展现状及存在问题,探讨了加快旅游地图网络化发展的策略与措施。     

GPS CORS系统中NTRIP传输技术的应用研究

NTRIP是一种播发实时差分定位改正信息的IP协议。本文讨论了NTRIP的组成、工作原理,并给出一个应用实例。     

三维地震技术在煤层顶板稳定性研究中的应用

龙固井田为全隐蔽的华北型煤田,位于巨野煤田中部,其首采扩大区主采煤层为3号煤层。考虑3煤层顶板稳定性主要受其顶板的构造信息和岩性信息影响,因此首先依据三维地震勘探综合解释成果及波阻抗反演解释成果对二者进行定量化,然后对波阻抗数据进行归一化处理,使得波阻抗数据和量化后的构造数据具有相同的变化范围及等量贡献。在此距离范围内构造和岩性的权值各为0．5,依此生成综合因素煤层顶板稳定性隶属度。分析3煤层顶板以上10m、20m处的综合因素煤层顶板稳定性隶属度图可以发现,该区3煤层顶板稳定性比较好。且其稳定性主要是受构造因素控制,岩性因素相对影响较小。     

Using Sequential Self-Calibration Method to Identify Conductivity Distribution: Conditioning on Tracer Test data

An iterative inverse method, the sequential self-calibration method, is developed for mapping spatial distribution of a hydraulic conductivity field by conditioning on nonreactive tracer breakthrough curves. A streamline-based, semi-analytical simulator is adopted to simulate solute transport in a heterogeneous aquifer. The simulation is used as the forward modeling step. In this study, the hydraulic conductivity is assumed to be a deterministic or random variable. Within the framework of the streamline-based simulator, the efficient semi-analytical method is used to calculate sensitivity coefficients of the solute concentration with respect to the hydraulic conductivity variation. The calculated sensitivities account for spatial correlations between the solute concentration and parameters. The performance of the inverse method is assessed by two synthetic tracer tests conducted in an aquifer with a distinct spatial pattern of heterogeneity. The study results indicate that the developed iterative inverse method is able to identify and reproduce the large-scale heterogeneity pattern of the aquifer given appropriate observation wells in these synthetic cases.