应用地理信息系统辅助山坡地潜在崩山灾害评估模式之建立

山坡地开发具有潜在的自然危险因子,人工开挖也会触动这些因子,因此,要做好土地管理工作,需从分析潜在崩山灾害类型以及开发区位两方面考虑。地形分析在工程、灾害评估等方面广为应用,本研究以张石角(1987)提出的“简确工程地质灾害调查与评估法”为依据,以山坡地丙种建地作为评估对象,利用地理信息系统所提供的空间分析及数据库功能,完成台湾省中、北部地区大范围的山坡地潜在灾害评估工作,其成果也将为政府部门所采用.     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

航片判译茅台赤水河沿岸的滑坡

作者采用1:1.5万黑白航片判译茅台赤水沿岸滑坡共41个；其中体积大于1．5万m^3的滑坡16个，判译准确率达88％，漏、错判2个；体积大于10万m^3的滑坡12个，判译准确率达94％，漏判1个；体积大于30万m^3的滑坡6个，判译准确率达100％；判译验证不稳定蠕动体2个，体积的大于或等于5万m^3。对区内滑坡的发育规律及破坏模式作了分析研究。     

遥感技术在地质灾害调查、监测和防治中的应用

遥感在地质灾害(滑坡、泥石流)识别方面,较常规方法有明显的优势,并能快速提供大面积地区的位置、分布、范围、规模、类型、发育环境等数据和图件。本文通过多时相、多平台遥感图像解译,了解它们的动态变化及发展趋势,这些信息为工程灾害评价及滑坡、泥石流防治工作提供了全面可靠的依据。 遥感技术在滑坡、泥石流灾害领域中的应用除遥感技术水平外还依赖于滑坡、泥石流信息机制、应用模型的研究及信息系统的支持。     

A landslip/debris flow in bilsdale,North York Moors,September 1976

The conditions prior to and the site and results of a debris flow are described. Baseline data collected after this extreme event are outlined. Similarities between antecedent conditions of this flow and others reported in the literature are noted. From the field evidence comment is made on the mobile nature of the flow which may be analogous to spontaneous liquefaction in sands.     

水岩作用对川藏公路102滑坡形成与演化的影响

10 2滑坡频繁活动造成了川藏公路运营的多次中断。本文立足于翔实的野外考察,从 10 2滑坡水岩作用的影响因素入手,指出川藏公路地区滑坡的水岩作用强烈且形式多样,并分析了水岩作用对 10 2滑坡形成与演化全过程的影响。最后,提出在 10 2滑坡防治中应重点考虑滑坡的水岩作用。     

Landslide Susceptibility Models Utilising Spatial Data Analysis Techniques. A Case Study from the Lower Deba Valley,Guipuzcoa (Spain)

A quantitative methodology for landslide susceptibility zonationis described and its application to a study area in the lower part of the Deba Valley (Guipúzcoa,Spain) presented. Susceptibility models were obtained on the basis of statisticalrelationships between known mass movements and conditioning factors. A landslide rupturehypothesis was set and a digital database consisting of seventeen causal factors layers constructed.The modelling procedure was implemented utilising a GIS. The susceptibility analysis methodis based on the Favourability Functions approach, and two different mathematicalframeworks: probability theory and Zadehïs fuzzy set theory. Several landslidesusceptibility models were produced and validated using different sets of independent landslide data.The predictive capability of models was determined.     

Simulating sensitivity of soil moisture and evapotranspiration under heterogeneous soils and land uses

Soil moisture (SM) plays an important role in land surface and atmospheric interactions. It modifies energy balance at the surface and the rate of water cycling between the land and atmosphere. In this paper we provide a sensitivity assessment of SM and ET for heterogeneous soil physical properties and for three land uses including irrigated maize, rainfed maize, and grass at a climatological time-scale by using a water balance model. Not surprisingly, the study finds increased soil water content in the root zone throughout the year under irrigated farming. Soil water depletes to its lowest level under rainfed maize cultivation. We find a ‘land use’ effect as high as 36 percent of annual total evapotranspiration, under irrigated maize compared to rainfed maize and grass, respectively. Sensitivity analyses consisting of comparative simulations using the model show that soil characteristics, like water holding capacity, influence SM in the root zone and affect seasonal total ET estimates at the climatological time-scale. This ‘soils’ effect is smaller than the ‘land use’ effect associated with irrigation but, it is a source of consistent bias for both SM and ET estimates. The ‘climate’ effect basically masks the ‘soils’ effect under wet conditions. These results lead us to conclude that appropriate representation of land use, soils, and climate are necessary to accurately represent the water and energy balance in real landscapes.     

Deterministic and probabilistic floor response spectra

The paper presents a comparative study for computing floor response spectra (FRS) for complex structures. For the purpose of validation and evaluation of the methods for practical application, a systematic comparison of two concepts, classical deterministic and probabilistic, was carried out as an example of a nuclear power plants structure. The deterministic method utilizes time history analyses compatible with the prescribed design response spectrum. The probabilistic method uses an analysis of random vibrations for defining the probabilistic FRS influenced by random seismic soil movement. The seismic input is a power spectral density function (PSDF) compatible with the design response spectrum. The probabilistic approach based on PSDF provides satisfying FRS with far less effort and time consumption needed for calculation.     

The use of the automatic inclinometric system for landslide early warning: the case of Cabella Ligure (North-Western Italy)

Following the flood events occurred in the 1993 autumn, a landslide affecting the village of Montaldo di Cosola was reactivated. Montaldo di Cosola is a small village located in North-Western Italy, on the Appennines Mountains. Historical data report of at least another similar episode occurred about one century ago.The landslide takes place over debris deposits, which are about 20–35 m deep, produced by an ancient landslide event. Underneath these debris deposits there is an altered layer of the calcareous-marly substratum of the Antola formation. The landslide, almost certainly triggered by the incision of the torrent Rio Montaldo, has a probable rotational geometry and takes place through slow and progressive continuous movements. The landslide typology impedes a precise dimensional definition. Only the order of magnitude of the main scarp width, which is of hundreds of meters, and the order of magnitude of the landslide volume, which is of some hundreds of thousands of cubic meters, can be indicated.A complex monitoring network has been installed in the area. This network includes an automatic inclinometric system (AIS) that automatically performs measurements, twice a day, along the entire length of a pipe that is 45 m deep. Measurements are taken every 50 cm and are then broadcasted to a remote station located in Torino.After the exceptional meteorological events occurred in October 2000, the AIS measured significant movements that have not yet stopped. On the basis of these available data it has been possible to locate the sliding surface at a depth of about 13 m at the level of a sandy–silty layer with some clay lenses inside. The movements measurements performed so far reveal a good correlation with the rainfalls. In particular it has been possible to identify a time lag of about 8–9 days between the occurrence of a rainfall peak and the corresponding peak in the recorded movements that were produced by these rainfalls.