Use of LIDAR‐derived images for mapping old landslides under forest

Large, deep‐seated landslides are common features in the Flemish Ardennes (Belgium). As most of these old (>100 years) landslides are located under forest in this hilly region, aerial photograph interpretation is not an appropriate landslide mapping method. This study tested the potential of LIDAR (Light Detection and Ranging) images for mapping old landslides under forest. Landslide inventory maps were created for a 125 km² area by applying the expert knowledge of seven geomorphologists to LIDAR‐derived hillshade, slope and contour line maps in a GIS environment. Each of the seven LIDAR‐based landslide inventories was compared (i) with the other six, (ii) with a detailed field survey‐based inventory, and (iii) with a comparable study in which topographic data were extracted from a topographical map. The combination of the percentage of field landslides indicated by an expert and the percentage of positional discrepancies (expressed in terms of positional mismatch) were used to evaluate the quality of the LIDAR‐based inventory maps. High‐quality LIDAR‐derived landslide inventory maps contain more than 70 per cent of the landslides mapped during the field survey, and have positional discrepancies smaller than 70 per cent when compared with the field survey‐based inventory map. Four experts and the combination map of all experts satisfied these criteria. Together the seven experts indicated all landslides mapped in the field. Importantly, LIDAR enabled the experts to find ten new landslides and to correct the boundaries of eleven (of the 77) landslides mapped during the field survey. Hence, this study showed that large‐scale LIDAR‐derived maps analysed by experienced geomorphologists can significantly improve field survey‐based inventories of landslides with a subdued morphology in hilly regions. Copyright © 2006 John Wiley & Sons, Ltd.     

GIS支持下基于CF方法的2013年芦山地震滑坡因子敏感性分析

本文依据研究区现有地形因子(高程、坡度、坡向、斜坡曲率)、地质因子(岩性、距深大活动断裂距离)和地震因子(PGA、距震中距离)等相关影响因子资料并结合地震区基本情况,以GIS技术作为操作平台,采用确定性系数法,开展较为详细的芦山地震区地震滑坡影响因子敏感性分析工作。首先,以GIS技术作为操作平台将地震滑坡的8个影响因子据研究区特征进行分级,构建不同影响因子分级的栅格图层进行地震滑坡分布相关参数统计; 其次,采用确定性系数法计算8个地震滑坡影响因子分级区间对应的CF值,分别提取出地震滑坡最为敏感分级区间以进行地震滑坡影响因子敏感性分析,从而衡量不同影响因子分级区间对地震滑坡易发性敏感程度。地震滑坡影响因子敏感性分析结果表明,除斜坡曲率因子与距震中距离因子对地震滑坡易发性不敏感外,其他6个影响因子对地震滑坡易发性均很敏感,分别是影响滑坡发生的主要地形、地质和地震因子。针对斜坡曲率因子和距震中距离因子对滑坡的易发性不是很敏感是否受内部其他影响因子限制所进行的分析与讨论结果表明,SW向很可能限制了斜坡曲率对地震滑坡易发性的敏感程度,地层岩性对距震中距离因子限制作用更为明显,除奥陶系、志留系外的地层岩性对距震中距离因子敏感性程度都有限制。文章所得成果具有一定的方法理论意义,对于防震减灾工作也具有一定参考意义。     

ANALYSIS OF METEOROLOGICAL CONDITION AND RESEARCH ON FORECAST OF LANDSLIDES AND DEBRIS FLOWS IN ZHEJIANG PROVINCE

1 INTRODUCTIONMeteorological factors, especially precipitation,have close links with geological calamities. Accordingto the statistics, more than 70% of the geologicalcalamities in China occur in rainy seasons. Manyresearchers are thus motivated to study …     

滑坡实时监测预警系统的实验室实现

用传感器对滑坡实施监测是一种有效的监测预警手段,但由于受一些因素的限制,在实验室进行滑坡监测技术有效性的研究方面仍有一定的难度。本文以振弦式传感器为例,提出了传感器辅助机械工装以完成传感器在实验室实现滑坡监测数据模拟采集的设计思路,并通过对模拟数据进行多次测量演算了传感器及其辅助装置的可靠性。同时,为便于对监测数据进行及时有效的管理和分析,还采用VC++语言所编制的管理程序对获取的监测数据实施有效的管理和分析。结果表明,对给定信号的监测效果好,响应快,误差小,能较好地模拟滑坡现场监测。     

指数平滑法及其在滑坡预报中的应用

指数平滑法是一种非统计性的预报方法，它具有计算过程简单，适应性好等优点，本文介绍的是其中的二次曲线指数平滑法及其在骨坡中，短期预报中的应用。     

InSAR技术在滑坡灾害中的应用研究进展

InSAR技术作为重要的对地观测技术之一,已在城市、矿山、地质灾害等地表形变监测领域得到广泛应用与探索,特别是在滑坡灾害形变监测中具有很强的实用性.为全面、准确及深入认识和梳理InSAR技术在滑坡灾害应用中的前沿科学问题、局限性、面临挑战及未来发展趋势,以期更好地服务于滑坡灾害的防治与监测.以InSAR技术滑坡灾害应用...     

黄河流域刘家峡—兰州段滑坡灾害的InSAR识别及成因分析

我国滑坡灾害频发,尤其是西部地区,滑坡的隐蔽性强且危害巨大,对其灾害隐患进行早期识别对防灾减灾意义重大.传统的人工排查、大地测量等手段在山区难以开展且耗时耗力,合成孔径雷达干涉测量技术(InSAR)作为新兴的遥感测量手段,可以更精确、高效地进行大范围的滑坡灾害隐患识别.以黄河流域刘家峡-兰州段为研究区,采用永久散射体I...     

贵州省降雨型滑坡预报模型及检验

本文利用贵州省2010—2017年630次降雨型滑坡资料以及国家气象台站和区域自动气象站逐小时降水资料，分析了贵州省降雨型滑坡的时空分布特征。基于5个不同时效降水指标与滑坡累积发生概率的拟合曲线公式，得到不同概率对应的5个降水指标的降水阈值，建立贵州省降雨型滑坡预报模型,并利用2018年新增滑坡样本对预报模型进行检验。结果表明：贵州省降雨型滑坡高发期主要集中在5—7月，其中6月滑坡发生概率最高，约48.6 %；7月次之，约34.9 %。当R1h、R3h、R6h、R24h、R3d分别大于等于26.9 mm、48.9 mm、62.9 mm、79.5 mm、92.0 mm时，发布滑坡预报预警。在降雨型滑坡预报模型中，随着5个不同时效指标的降水量增大，降雨型滑坡累积发生概率变化呈现前后增加缓慢，中间快速增加的变化特征。模型检验结果表明贵州省降雨型滑坡预报模型有一定的准确性，且5个降水指标均具有一定的实用性，其中利用R3d开展降雨型滑坡预报准确率最好。     

Glacial activity and paraglacial landsliding in the Devensian Lateglacial: evidence from Craig Cerrig-gleisiad and Fan Dringarth,Fforest Fawr (Brecon Beacons), South Wales

The tongue-shaped mass of debris and associated ridges on the cirque floor below Craig Cerrig-gleisiad, Brecon Beacons National Park is important and controversial because it has been attributed to more than one glacier advance during the Late Devensian. A new origin is proposed involving landslide development from the collapse of part of the western headwall followed by a single phase of glacier development in the Loch Lomond Stadial (Younger Dryas), which reworked the landslide sediments. Evidence for this landslide, which provides useful criteria for differentiating moraines formed by small glaciers from landslides, lies in tension cracks, backward-tilted blocks and bedrock joints dipping out of the western headwall, together with lateral levées, upstanding termini and angular clasts with only occasional, indistinct striae on the tongue-shaped mass, which is interpreted as a flowslide. Glacier reworking of debris in the upper part of the Cwm Cerrig-gleisiad landslide is indicated by subparallel ridges rising to 20 m above the cirque floor containing abraded clasts (16-32% striated). This interpretation is supported by a comparison with the morphological and sedimentary characteristics of a neighbouring landslide at Fan Dringarth, where no glacier developed in the Loch Lomond Stadial. The existence of paraglacial landsliding has significant palaeoenvironmental implications leading to: (1) erroneously large estimates of equilibrium line depression ($Δ$ELA) in the Loch Lomond Stadial; (2) consequent underestimates of summer palaeotemperatures and/or overestimates of the contribution of wind-drifted snow to glacier accumulation; and (3) larger moraines than usual and overestimation of the efficacy of glacial erosion because of antecedent processes.