Hazard Assessment of Co-seismic Landslides Based on Information Value Method: A Case in 2018 MW6.6 Hokkaido Earthquake, Japan     

WEN Boyu  XU Chong  HE Xiangli  MA Siyuan  SHAO Xiaoyi  LI Kai  ZHANG Zhongjian  LI Zhengfang 《中国地震研究》2020,34(1):64-80

An M_W6.6 earthquake occurred in eastern Hokkaido, Japan on September 6^th, 2018. Based on the pre-earthquake image from Google Earth and the post-earthquake image from high resolution (3 m) planet satellite, we manually interpret 9 293 coseismic landslides and select 7 influencing factors of seismic landslide, such as elevation, slope, slope direction, road distance, flow distance, peak ground acceleration (PGA) and lithology. Then, 9 293 landslide points are randomly divided into training samples and validation samples with a proportion of 7:3. In detail, the training sample has 6 505 landslide points and the validation sample has 2 788 landslide points. The hazard risk assessment of seismic landslide is conducted by using the information value method and the study area is further divided into five risk grades, including very low risk area, low risk area, moderate risk area high risk area and very high risk area. The results show that there are 7 576 landslides in high risk area and very high risk area, accounting for 81.52% of the total landslide number, and the landslide area is 22.93 km², accounting for 74.35% of the total area. The hazard zoning is in high accordance with the actual situation. The evaluation results are tested by using the curve of cumulative percentage of hazardous area and cumulative percentage of landslides number. The results show that the success rate of the information value method is 78.50% and the prediction rate is 78.43%. The evaluation results are satisfactory, indicating that the hazard risk assessment results based on information value method may provide scientific reference for landslide hazard risk assessment as well as the disaster prevention and mitigation in the study area.  相似文献   

稻虾轮作模式面源污染排放特征及其能值评估     

陶玲  彭亮  代梨梨  杨镇  陈思媛  可毅  李谷 《湖泊科学》2023,35(1):168-180

为探明稻虾轮作模式面源污染排放特征并合理评价该模式的环境可持续性,通过对江汉平原稻虾轮作模式小龙虾养殖排放尾水中总氮(TN)、总磷(TP)、COD和氨氮(NH₃-N)浓度进行监测,对稻虾轮作模式稻田养殖小龙虾的排污系数进行了估算,并采用等标污染负荷法进行了主要污染物解析。运用能值分析方法对稻虾轮作模式进行了包含面源污染的能值评估,对比单季稻模式,对其可持续发展能力进行了定量评价。结果表明：江汉平原稻虾轮作模式小龙虾养殖排放尾水中TN、TP、COD和NH₃-N的浓度范围分别为0.53～5.36、0.12～0.70、6.60～78.39和0.34～1.75 mg/L,TN、TP和COD平均排放浓度高于《地表水环境质量标准》(GB 3838-2002)Ⅲ类水质标准。等标污染负荷法分析结果表明TN的等标负荷比最高,是稻虾轮作模式面源污染控制的关键污染物。稻虾轮作模式小龙虾养殖排放尾水中TN、TP、COD和NH₃-N的排污系数分别为2.994、0.458、35.132和1.405 kg/t,表明稻虾轮作模式面源污染排放系数较低,对...  相似文献   

利用Landsat时序NDVI数据进行新疆石河子垦区灌溉作物分类   总被引：3，自引：2，他引：1  

汪松  王斌  刘长征  王思远 《测绘通报》2016,(9):56-59

精确的农作物分类信息对于农业环境评估、水资源利用规划非常重要,尤其是在干旱、半干旱地区。本文利用30 m分辨率的Landsat NDVI时间序列数据进行了新疆石河子垦区混合农作物精确区分的潜力研究。首先利用S-G滤波重构了Landsat NDVI时间序列,然后基于SVM模型对研究区域农业类型进行了精确分类。在SVM分类模型作用下,S-G重构后的时间序列有效地将该地区棉花、玉米、小麦等主要作物区分开来,精度高于0.86,Kappa系数大于0.82。结果表明,S-G滤波能够有效提高NDVI时间序列数据质量;TM影像时间序列在监测干旱、半干旱地区的作物类型和种植方式随时间的变化方面存在巨大潜力。  相似文献   

Distribution,sources and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in surface soils of the Yellow River Delta,China   总被引：1，自引：0，他引：1  

Hongming Yuan  Tiegang Li  Xigui Ding  Guangming Zhao  Siyuan Ye 《Marine pollution bulletin》2014

PAH concentrations of 61 surface soil samples collected from the Yellow River Delta (YRD), China were measured to determine occurrence levels, sources, and potential toxicological significance of PAHs. The total concentrations of ∑PAHs ranged from 27 to 753 ng/g d.w., with a mean of 118 ± 132 ng/g. The highest concentrations was found in the mid-southern part of the YRD (753 ng/g), which was associated with the oil exploration. The ratios indicated that the PAHs throughout the YRD were mostly of pyrogenic origin; while various sites in mid-southern part in the region were derived mainly from the petrogenic sources. Multivariate statistical analyses supported that the PAHs in surface soils of the YRD were principally from the coal and biomass combustion, petroleum spills, and/or vehicular emissions. The toxic assessment suggested that the PAHs in soils were at low potential of ecotoxicological contamination level for the YRD.  相似文献   

青藏高原典型植被生长季遥感模型提取分析   总被引：2，自引：0，他引：2  

常清  王思远  孙云晓  殷慧  尹航 《地球信息科学学报》2014,16(5):823-816

物候变化是衡量全球气候变化最直接、敏感的指示器,针对青藏高原这个独特地域单元上特殊的高寒植被进行关键物候期遥感提取模型及植被物候时空变化的研究具有重要的意义。本文首先以反距离加权空间插值算法与Savitzky-Golay滤波算法相结合的数据重建模型获得高质量2003-2012年青藏高原MODIS归一化植被指数(NDVI)数据。在此数据基础上,分别利用动态阈值法、最大变化斜率法、logistic曲线拟合法3种遥感植被生长季提取模型,对青藏高原地区两种典型植被的生长季(SOS生长季开始期,EOS生长季结束期,LOS生长季长度)进行提取。通过对3种模型提取结果的对比分析,并结合日均温模型对提取结果的验证发现,动态阈值法为青藏高原地区典型植被生长季的最优遥感提取模型。该模型对近10 a的高分辨率典型高寒植被物候参量的反演及时空变化特征分析表明,受青藏高原水热及海拔梯度的影响,青藏高原植被物候变化呈现出从东南向西北的空间分异规律,随春季温度的升高,近10 a来青藏高原高寒草地总体呈现生长季开始期(SOS)提前(0.248 d/a)的趋势。  相似文献   

基于SRTM DEM的地形起伏度对天水市黄土滑坡的影响分析   总被引：2，自引：0，他引：2  

宿星  魏万鸿  郭万钦  王思源  王国亚  吴玮江  叶伟林 《冰川冻土》2017,39(3):616-622

以天水市辖区30 m分辨率的SRTM DEM数据为基础,首先利用GIS空间分析模块中邻域统计分析法,依次选取2×2、3×3、4×4、…、28×28、29×29、30×30共29个矩形邻域分析窗口,运用均值变点分析法进行最佳计算单元的计算分析。结果表明：12×12的网格大小（12.96×10⁴ m²）为曲线突变的拐点,作为曲线由陡变缓的阈值,确定12×12的网格大小（12.96×10⁴ m²）为研究区地形起伏度计算的最佳单元,生成研究区地形起伏度分级图。进而采用确定性系数法（CF）、证据权法、信息量法和条件概率法对研究区发育的黄土滑坡灾害与地形起伏度之间的相关关系进行了定量分析。研究结果表明,区内地形起伏度影响因子层中地形起伏度60~120 m的分级因子层为黄土滑坡灾害的易发因子层,而其中60~90 m区间的值最大,为黄土滑坡灾害的优势因子区间,对滑坡的响应最敏感。  相似文献   

Temporal change in the landscape erosion pattern in the Yellow River Basin,China     

W. Siyuan  L. Jingshi  Y. Cunjian 《International journal of geographical information science》2013,27(10):1077-1092

Using Landsat TM data from 1995 and 2000, changes in the landscape erosion pattern of the Yellow River Basin, China were analysed. The aim was to improve our understanding of soil‐erosion change so that sustainable land use could be established. First, a soil‐erosion intensity index model was developed to study soil‐erosion intensity change in the study area. Over the 5 years, the areas of weak erosion, moderate erosion, severe erosion, and very severe erosion all increased. The area of weak erosion increased dramatically by 7.94×10⁵ ha, and areas of slight erosion and acute erosion decreased by 1.93×10⁶ ha and 4.50×10⁴ ha, respectively. The results show that while the intensity of soil erosion has gradually been decreasing as a whole, in some regions the soil erosion is becoming more severe. Based on landscape indices, the pattern of changes in soil erosion over the past 5 years was analysed. The changes in landscape pattern of soil erosion resulted from human activities. Analysis showed that human impact increases fragmentation, having three major effects on landscape pattern, reduction in patch area, variations in patch shape, and changes in spatial pattern. In the study area, population growth, farming, governmental policy and forest degradation are the major factors causing soil erosion change over a 5‐year period.  相似文献   

Trace metals in porewater of surface sediments and their bioavailability in Jiaozhou Bay,Qingdao, China     

Siyuan Ye  Edward A. Laws  Xigui Ding  Hongming Yuan  Guangming Zhao  Jin Wang 《Environmental Earth Sciences》2011,64(6):1641-1646

Samples of porewater and the edible tissue of mottled clams, Ruditapes variegatus, were collected simultaneously at each of 12 stations from Jiaozhou Bay near Qingdao, China, in June of 2003. Chemical analysis focused on trace metals and major elements. Porewater concentrations of Cd, Cr, Pb, and Zn were distributed in a bimodal fashion among the 12 stations, with mean concentrations at six of the stations being 8–32 times mean values at the other six stations. The concentrations of the same metals in clams were remarkably similar among stations, the coefficients of variation being only 12–37%. Calculations performed with the computer program PHREEQC indicated that Pb and Cr in porewater were present only in the +2 and +3 states, respectively, and because dissolved Cd and Zn exist only in the +2 state, the bimodal distribution of these four metals likely reflects secondary effects associated with their scavenging by Fe and/or Mn under oxidizing conditions and subsequent dissolution in the reducing environment of the porewaters. Consistent with this hypothesis is the fact that the distribution of high and low metal concentrations was closely correlated with the granularity of the sediment, with lower metal concentrations associated with relatively coarse sediment. Comparison of published biological concentration factors with the ratios of metal concentrations in the clams to porewater metal concentrations indicated that the porewaters were not the primary sources of the metals in the clams. Mixing processes in the bay likely account for the rather uniform concentrations of metals in clam tissue.  相似文献   

滨海湿地咸水冲淡驱动机理     

高茂生  叶思源  袁红明  赵广明  丁喜桂 《海洋地质前沿》2011,(9):40-43

海陆界面水体相互作用研究是当代国际海岸带生态水文学的热点.滨海湿地的生态水文环境脆弱,浅层地下水及盐度梯度变化对其生长和发育起着控制作用.咸水冲淡驱动力主要是地下水动力作用、盐度驱动下的水化学运动作用和海洋潮汐作用的叠加效应.通过国内外学者近30年的研究成果分析了滨海湿地咸水冲淡研究程度及进展情况,认为掌握咸水冲淡驱动...  相似文献   

Application of a Discrete-Continuum Model to Karst Aquifers in North China   总被引：7，自引：0，他引：7  

by Qiang Wu  Wanfang Zhou  Guoying Pan  and Siyuan Ye 《Ground water》2009,47(3):453-461

A generalized discrete-continuum model is developed to simulate ground water flow in the karst aquifers of North China. The model is a hybrid numerical flow model, which takes into account both quick conduit flow and diffusive fissure flow. The conduit flow is represented by a discrete network model, and the fissure flow is modeled by a continuum approach. The developed model strongly emphasizes the function of the conduits in the flow fields. They control the general drainage pattern, as demonstrated in the simulation of a complex karst aquifer in North China. The model reproduces reasonably well the flow field in response to an unanticipated discharge of ground water from the karst aquifer into an underground mine based on the aquifer parameters that are manually calibrated from a multiple-well pumping test. Sensitivity of the model to the aquifer parameters was evaluated in the context of the case study.  相似文献