Predicting global landslide spatiotemporal distribution： Integrating landslide susceptibility zoning techniques and real-time satellite rainfall estimates

Landslides triggered by rainfall can possibly be foreseen in real time by jointly using rainfall intensity-duration thresholds and information related to land surface susceptibility. However, no system exists at either a national or a global scale to monitor or detect rainfall conditions that may trigger landslides due to the lack of sufficient ground-based observing network in many parts of the world. Recent advances in satellite remote sensing technology and increasing availability of high-resolution geospatial products around the globe have provided an unprecedented opportunity for such a study. In this paper, a framework for developing a preliminary real-time prediction system to identify where rainfall-triggered landslides will occur is proposed by combining two necessary components： surface landslide susceptibility and a real-time space-based rainfall analysis system （http：//trmm.gsfc.nasa.gov）. First, a global landslide susceptibility map is derived from a combination of semi-static global surface characteristics （digital elevation topography, slope, soil types, soil texture, land cover classification, etc.） using a GIS weighted linear combination approach. Second, an adjusted empirical relationship between rainfall intensity-duration and landslide occurrence is used to assess landslide hazards at areas with high susceptibility. A major outcome of this work is the availability for the first time of a global assessment of landslide hazards, which is only possible because of the utilization of global satellite remote sensing products. This preliminary system can be updated continuously using the new satellite remote sensing products. This proposed system, if pursued through wide interdisciplinary efforts as recommended herein, bears the promise to grow many local landslide hazard analyses into a global decision-making support system for landslide disaster preparedness and mitigation activities across the world.     

地理信息系统支持下的滑坡灾害分析模型研究

运用GIS等技术手段 ,集成相关模型对滑坡变形失稳危险性进行分析是一个重要研究内容。进行有效的滑坡灾害分析的关键是采取适当的分析模型及模型单元。通过对已有的基于GIS的分析模型的综合论述 ,对各种分析模型及模型单元的特点及其局限性进行了详细分析 ,并取得一些重要认识。     

微型桩单桩加固滑坡体的模型试验研究

通过开展滑坡基本参数试验和微型桩加固滑坡体的模型试验,研究微型桩单桩加固滑坡体的承载机理、受力情况及破坏模式。结果表明:微型桩可有效提高滑坡的稳定系数,采用微型桩加固滑坡后,可将滑坡的稳定系数由0.96提高至1.35;微型桩所受的滑坡推力呈上小下大的三角形分布,滑床抗力呈上大下小的三角形分布,且随加载量的增加合力作用点逐渐向滑面靠近;微型桩于滑面附近发生破坏,其破坏模式可判断为弯剪破坏。     

Partitioning coefficients between olivine and silicate melts

Variation of Nernst partition coefficients (D) between olivine and silicate melts cannot be neglected when modeling partial melting and fractional crystallization. Published natural and experimental ^{olivine/liquid}D data were examined for covariation with pressure, temperature, olivine forsterite content, and melt SiO₂, H₂O, MgO and MgO/MgO + FeO^total. Values of ^{olivine/liquid}D generally increase with decreasing temperature and melt MgO content, and with increasing melt SiO₂ content, but generally show poor correlations with other variables. Multi-element ^{olivine/liquid}D profiles calculated from regressions of D REE–Sc–Y vs. melt MgO content are compared to results of the Lattice Strain Model to link melt MgO and: D₀ (the strain compensated partition coefficient), E_M³⁺ (Young's Modulus), and r₀ (the size of the M site). Ln D₀ varies linearly with Ln MgO in the melt; E_M³⁺ varies linearly with melt MgO, with a dog-leg at ca. 1.5% MgO; and r₀ remains constant at 0.807 Å. These equations are then used to calculate ^{olivine/liquid}D for these elements using the Lattice Strain Model. These empirical parameterizations of ^{olivine/liquid}D variations yield results comparable to experimental or natural partitioning data, and can easily be integrated into existing trace element modeling algorithms. The ^{olivine/liquid}D data suggest that basaltic melts in equilibrium with pure olivine may acquire small negative Ta–Hf–Zr–Ti anomalies, but that negative Nb anomalies are unlikely to develop. Misfits between results of the Lattice Strain Model and most light rare earth and large ion lithophile partitioning data suggest that kinetic effects may limit the lower value of D for extremely incompatible elements in natural situations characterized by high cooling/crystallization rates.     

云南陇川县"2004-07-05"特大滑坡泥石流灾害及防治对策

云南德宏州陇川县2004年7月5目发生了近100a一遇的特大滑坡泥石流灾害。这次灾害点多、面广,波及到全县11个乡镇,并且灾害几乎同时发生。因灾死亡13人,4人失踪,直接经济损失约2亿元,其灾害的严重性可见一斑。因灾区地处滇西横断山地,岭谷相间,地形高差、山坡坡度及河、沟谷比降都比较大;地质条件复杂,出露岩层为易风化的花岗岩及片麻岩,雨季5-10月降水丰沛而集中,这些对滑坡泥石流的发育极为有利：不合理的人类经济活动(如陡坡耕作、挖方填方式的公路建设等)则加剧了滑坡泥石流灾害的发生。加之7月5目区域性暴雨及局部特大暴雨的激发,最终引发了此次灾害。暴雨是陇川县07-05灾害最直接也是最根本的原因。通过对这次灾害的实地考察,在掌握本区的社会经济条件和自然属性前提下,总结了此次灾害的特点。此次灾害具有如下几个方面的特点：灾种多样,灾害的链武特征明显;滑坡多表现为高位、高势能、高速特征,而泥石流多发生在沟口;滑坡泥石流规模小,但点多面广：漂木流危害严重。在明确陇川县07-05灾害特点和成因的前提下,提出了有针对性的近期、中远期防灾、减灾对策。     

三峡库区巨鱼沱滑坡地质特征及防治研究

介绍了三峡库区万州巨鱼沱滑坡的结构特征和变形特征,从滑坡形成条件和诱发变形因素两方面分析了滑坡形成的原因,对滑坡在各工况下的稳定性进行了分析和计算,提出了以预应力锚索抗滑桩为主的综合治理措施,对三峡库区滑坡灾害的研究和治理具有参考价值。     

植被覆盖对暴雨型滑坡影响的初步分析

根据遥感资料、地形数据和历史观测资料等,以江西省为例,分析了森林植被覆盖率、森林生物量和暴雨型滑坡的空间分布,以及森林植被类型对大气降水的截留作用。分析结果初步揭示了植被覆盖对滑坡的影响,认为植被覆盖程度高、生物量多和植被覆盖差、生物量低的中低山区,都可能发生滑坡灾害。不同林冠对降水的截留作用,减缓了降水对斜坡的冲刷,但当降水强度达到或超过暴雨强度时,森林对降水的截留率减小。同等地质环境条件下,植被覆盖率低,滑坡较易发生,但当降水强度较大时,特别是达到诱发滑坡灾害发生的临界值时,植被对滑坡体的重力作用则更加重了滑坡的发生。植被覆盖对滑坡的影响主要取决于降水强度。高森林覆盖区发生滑坡的雨量临界值大于森林覆盖率差的区域。     

面向新世纪的滑坡、泥石流遥感技术

本文回顾了我国20年滑坡、泥石流遥感调查的成绩、方法技术特征及存在的问题;指出改善现有滑坡、泥石流遥感调查方法技术的迫切性,并展望滑坡、泥石流遥感调查的新技术.     

Landslide detection using probability regression,a case study of Wenchuan,northwest of Chengdu

Landslides have become one of the dominant disasters all around the world. Reliable and efficient landslide mapping is playing a significant role in landslide studies. However, to the best of our knowledge, there is little research on detecting multiple landslides simultaneously from images to stimulate practical cases. In this work, we propose a regression model to detect landslides and investigate its applicability in practical cases. It synthesizes contextual, spectral and geometric features. Among the test images, F-measure of landslide detection has a range between 0.771 and 0.998, validating its robustness and high efficiency.     

Role of anthropogenic volatile organic compounds and nitrogen oxides as ozone precursors in the wintertime over East Asia

As an exercise in model sensitivity, the Models-3 Community Multiscale Air Quality (CMAQ) modeling system with meteorological fields from the Regional Atmospheric Modeling System (RAMS) was applied to study the response of photochemical oxidants to systematic increases in anthropogenic volatile organic compounds (VOC) and nitrogen oxides (NO_x) emissions in January 1997 over East Asia. Three simulations-one base case and two sensitivity simulations were carried out. Two sensitivity simulations were performed by assuming a 35% separate increase in anthropogenic VOC and NO_x emissions comparing with the base case. Biogenic VOC emissions were held constant across the sensitivity simulations. To evaluate the model performance, ozone mixing ratios (O₃) from the base case simulation were compared with surface observations at five remote sites in Japan, and it was found that the model reproduces most of the important features in the observations. Monthly average O₃ concentrations in the daytime were examined to gain an understanding of how the increase in anthropogenic emissions affected the overall chemical system for each sensitivity simulation.