Acquiring high-resolution topography and performing spatial analysis of loess landslides by using low-cost UAVs

The Loess Plateau is a region in China prone to frequent geological disasters, where thousands of loess landslides can be found. Conventional field survey methods are inadequate for the requirements of fine spatial analysis of landslides. Due to its numerous advantages (fast, efficient, low cost, safe, and able to acquire high-resolution data), structure from motion (SfM) technique to photogrammetric orientation of flights and modeling applied to photographs taken by unmanned aerial vehicles (UAVs) equipped with a camera has become a powerful new tool for the generation of high-resolution topography that has emerged in recent years, which has become a powerful new technique for acquiring high-resolution topographic data. In this study, we conducted nearly two months of field UAV surveys of loess landslides on the Loess Plateau, eventually established 3D digital models for 11 loess landslides, and produced high-resolution digital orthophoto maps (DOMs) and digital elevation models (DEMs). High-resolution spatial analysis of the loess landslides (mainly including characteristic parameter extraction, topography profile analysis, surface feature analysis, and hydrologic analysis) was performed using Agisoft PhotoScan, ArcGIS 10.2, Global Mapper 17, and Origin Pro 9.0. The UAV technique allows us to further understand the micro-level internal spatial and structural characteristics of loess landslides. Moreover, not only does it allow us to accurately measure the characteristic geometric parameters but also enables us to detect the surface details of loess landslides (e.g., textures, fissures, and micro-landforms). Manifestly, we can also deduce the original structural characteristics and possible inducement mechanism of landslides based on a combination of high-resolution data acquired by UAVs, proper ground surveys, and theoretical knowledge. In summary, the low-cost UAVs are highly and especially suitable for surveys and digital terrain analysis of landslides on the Loess Plateau with sparse vegetation.     

Assessment of economic losses from tropical cyclone disasters based on PCA-BP

Tropical cyclones are the most common natural disasters in coastal regions and are the most costly in terms of economic losses. Economic loss assessment is the basis for disaster prevention and alleviation and for insurance indemnification. We use data from 1970 to 2008 for Zhejiang Province, China, in this study evaluating economic losses. We convert direct economic losses from tropical cyclone disasters in Zhejiang Province into indices of direct economic losses. To establish our assessment model, we process disaster-inducing assessment factors, disaster-formative environments and disaster-affected bodies using the principal component analysis method, and we abstract the principal component as the input of a BP neural network model. We found in the actual assessments of five tropical cyclones affecting Zhejiang Province in 2007 and 2008 that the post-disaster loss assessment values of tropical cyclones were higher than the actual losses, but that for more severe storms, the gap was smaller. This reflects the beneficial effect of efforts toward disaster prevention and alleviation for severe tropical cyclones. Pre-assessments based on relatively accurate forecast values of wind and precipitation at the start of a tropical cyclone have been in accordance with the post-disaster assessment values, while the pre-assessment results using less accurate forecast values have been unsatisfactory. Therefore, this model can be applied in the actual assessment of direct economic loss from tropical cyclone damage, but increasingly accurate forecasting of wind and precipitation remains crucial to improving the accuracy of pre-assessments.     

柴达木盆地西部跃进二号油田早渐新世沉积相研究

目前在柴达木盆地西部跃进二号油田沉积相研究工作中,存在对微相类型争议性大、展布特征不精细等问题,这些问题制约着油田高含水期的精细开发。因此,根据沉积学基本原理,采用地质相识别(包括岩石学标志和沉积构造标志)与测井相分析(包括自然伽马和自然电位的曲线特征)的综合研究方法,细化该油田早渐新世辫状河三角洲平原、辫状河三角洲前缘、滨浅湖沉积亚相,得出水上分流河道、泛滥平原、水下分流河道、河口坝、远砂坝、席状砂、分流间湾、砂坝、砂滩、滨浅湖泥10种微相。该套地层纵向从下至上具有完整的辫状河三角洲平原-辫状河三角洲前缘-滨浅湖的退积式正旋回相序。结合沉积微相平面展布和纵向相序,跃进二号油田早渐新世这套油藏存在2种类型的沉积模式:辫状河三角洲模式和湖泊模式。     

分形理论与灰色系统理论在南岭地区地质异常圈定和金矿资源预测中的应用

应用分形理论研究了南岭地区地质弄常及其圈定方法，结合灰色系统理论对该区的金矿资源进行了预测。通过研究，圈定了10个地质异常区和7个金成矿远景区，为南岭地区金矿地质勘查提供了依据。     

中国东北平原西部荒漠化现状、成因及其治理途径研究

中国东北平原西部土地荒漠化,主要表现为土地沙漠化和土地盐碱化,它属于荒漠化的两种类型。东北 平原西部分布着科尔沁沙地和松嫩沙地,前者是全国五大沙漠之一。文章全面、系统地对该地区编制了 1∶1000000荒漠化图和量算出土地沙漠化面积。东北平原西部土地沙漠化面积为72280.6km2,占土地总面积的 22.2%。自20世纪50年代至80年代末,土地沙漠化面积迅速扩大,平均每年以1.5%～3.7%的速度递增;自9 年代以来,沙漠化呈现出逆转趋势,但就总体而言,沙漠化发展仍然大于逆转。东北平原西部土地盐碱化面积 33850.79km2,占土地总面积10.44%,主要分布在松嫩平原,面积为23329.19km2,占土地总面积15.2%,它是世 界上苏打盐碱化土壤的三大片之一,土地盐碱化每年以1.4%～2.5%速率正在发展。所以,该地区的土地荒漠化 不仅制约着当地农、牧业和农村经济的发展,影响周围和毗邻国家的生态环境安全,而且已危及当地人民的生存。 东北平原西部荒漠化的形成有自然因素和人为因素,前者有物源和气候变化等原因,后者有草原超载过牧、滥 垦、滥伐滥櫵、乱挖,河流上中游修建水库等原因,以及冻融作用的特殊原因,致使荒漠化形成和发展。     

山西富东煤矿水害类型分析及其防治建议

富东煤矿主采煤层为石炭系上统太原组8、9、12、15上、15下号煤。近年来,随着开采水平的不断延伸,矿井水害日益呈现,对采掘工作面人员及安全生产构成威胁。以涌水水源与导水通道为划分原则,将整合后的富东煤矿面临的水害类型划分为采(古)空区及相邻矿井开采积水水害、含水层突水水害、断层破碎带突水水害、岩溶陷落柱水害以及地表水体突水水害,并分析了各种水害类型特点及其对煤矿安全生产的影响程度,认为在煤层开采过程中,导水裂隙带直接进入第四系松散强含水体或断层破碎带,若支护不当,雨季沟谷中的地表径流、各种含水层中地下水以及上覆煤层采空区积水都会通过断层及陷落柱等导水构造发生水力联系,对矿井造成威胁。指出了矿井水害防治重点,并提出了相应的防治水建议。     

基于SPCA和AHP联合方法的滦河流域生态环境脆弱性变化规律分析

基于生态敏感性-生态恢复力-生态压力度概念模型评价体系,选取表征地形、地表、气象、土壤、植被及社会经济因子的15项多系统评价指标,应用空间主成分分析（SPCA）与层次分析（AHP）联合方法,对滦河流域1985年、1995年和2005年3期生态环境进行脆弱性评价,并进行量化分级,获得流域生态环境脆弱性变化规律和成因机制。结果表明：流域整体脆弱性等级有减小趋势,潜在脆弱区域面积逐渐增大,而重度脆弱区域明显减小;西北山地和冀东沿海地区变化较为剧烈;人类活动已经取代自然条件,成为影响滦河流域生态系统的关键因子;流域人口的快速增长、气候条件的改变以及土地资源的不合理利用是区域脆弱性变化的主要驱动力。     

新疆东天山突出山铜铁矿床地球化学特征与地质意义

突出山铜铁矿床是东天山雅满苏石炭纪弧前-岛弧带中代表性的铁多金属矿床, 矿体呈透镜状、脉状、似层状赋存于上石炭统底坎尔组下亚组火山岩中。矽卡岩阶段包裹体均一温度为151℃~>380℃, 盐度为1.91%~23.18% NaCl_eq, 密度为0.76~1.09 g/cm³, 热液硫化物阶段包裹体均一温度为101℃~280℃, 盐度为0.35%~23.05% NaCl_eq, 密度为0.74~1.13 g/cm³, 表明成矿流体属于中-高温、中-低盐度、中-低密度的NaCl-H₂O体系。(绿泥石)绿帘石矽卡岩、磁铁矿(镜铁矿)矿石、含磁铁矿灰岩的稀土配分模式均为轻稀土相对富集的右倾型(LREE/HREE=2.85~9.21), 以出现负铕异常(δEu=0.22~1.09)和铈异常不发育为特征, 与底坎尔组火山岩相似, 表明成矿物质来源于底坎尔组火山岩。矿区矽卡岩可能是火山热液交代碳酸盐岩形成的, 成矿条件为中-高温、较为宽广的氧化还原环境, 矿床成因属火山热液交代型。     

Investigation of the sulfur speciation during chalcopyrite leaching by moderate thermophile Sulfobacillus thermosulfidooxidans

The surface sulfur speciation of chalcopyrite leached by moderately thermophilic Sulfobacillus thermosulfidooxidans was investigated by employing scanning electron microscopy (SEM), X-ray diffraction (XRD) and sulfur K-edge X-ray absorption near edge structure spectroscopy (XANES), accompanying with the leaching behavior elucidation. Leaching experiment showed that there was an optimum range of the redox potential for chalcopyrite dissolution. Leaching products were found accumulating during the leaching process, which might be jarosite according to the XRD analysis. The sulfur K-edge spectra indicated that chalcocite might be the intermediate sulfur compound under a critical redox potential, which might explain the existence of optimum range of the redox potential and provide an evidence for the two-step leaching model of chalcopyrite at low Eh. In addition, the results of sulfur K-edge spectra showed jarosite would accumulate on mineral surface, which might be the main component of the passivation layer.