A survey to determine levels of chlorinated pesticides and PCBs in mussels and seawater from the Mid-Black Sea Coast of Turkey     

Kurt PB  Ozkoc HB 《Marine pollution bulletin》2004,48(11-12):1076-1083

A mussel and seawater monitoring survey was conducted at six sampling points between Yalikoy (Ordu) and Sinop in 1999-2000 along the Mid-Black Sea Coast of Turkey in order to assess concentrations of organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs). Chlorinated pesticides and PCBs were measured in the mussel Mytilus Galloprovincialis and in seawater. In the mussel samples, the most common pollutants in terms of average concentration per g of wet weight (ww), were DDT (max. 1800 pg/gww, min. 240 pg/gww) and its metabolites DDD (max. 5400 pg/gww, min. 240 pg/gww) and DDE (max. 2800 pg/gww, min. 70 pg/gww). Also, dieldrin, heptachlor and HCB were notable contaminants in the mussel samples. PCBs were determined in none of the biota or seawater samples. The concentrations of the OCs and PCBs in mussels were higher in coastal areas receiving river discharges and close to the largest city of the region, Samsun (especially in sampling points in the harbour area). The well-known long persistence of DDTs and other chlorinated compounds was confirmed by residues of these pollutants measured in mussels. On the other hand, even though the usage of such kind of persistent compounds in Turkey was banned, there may still be illegal usage and it is not certain whether the application of these compounds did end in the region.  相似文献   

 GIS在矿产资源开发状况遥感动态监测中的应用   总被引：9，自引：0，他引：9  

刘琼  聂洪峰  吕杰堂  洪顺英  周英杰 《国土资源遥感》2005,16(1):61-65

为建立全国性的矿产资源开发状况数据库系统，以山西省晋城市和江西省崇义县矿产资源开发状况遥感动态监测成果为基础 ，通过GIS 强大的空间数据管理功能，对所收集的数据进行管理，建立了具有浏览编辑、查询检索、统计分析及动态监测等特点的空 间数据库系统。本文就建立这一数据库系统的技术方法、设计思路、系统组成和GIS的应用等方面进行了阐述。  相似文献   

基于ASP.NET的滑坡实时监测数据网上发布系统设计与实现   总被引：5，自引：0，他引：5  

张像源 《中国地质灾害与防治学报》2005,16(4):120-123

基于Asp．Net是目前数据库开发应用的新趋势。文章分析了Asp．Net特点的条件下，提出利用．net技术，采用Ado．Net数据访问组件，建立基于用户层、数据库服务层、业务逻辑层的3层结构框架的地质灾害实时数据发布系统。并从数据库表设计、功能设计等方面进行了系统构建的分析，结合身份验证、监测数据的发布、监测曲线的发布等方面说明了系统实现过程，最后给出了一个基于此设计建立的实例，说明了通过Internet采用最新的．net技术，可以便利地建立耦合最新的、实时的、多类滑坡动态监测数据、滑坡基础灾害资料、实时气象数据等于一体的图文并茂的滑坡灾害网上实时发布系统。  相似文献   

Monitoring land subsidence in Semarang,Indonesia   总被引：1，自引：0，他引：1  

Muh Aris Marfai  Lorenz King 《Environmental Geology》2007,53(3):651-659

Semarang is one of the biggest cities in Indonesia and nowadays suffering from extended land subsidence, which is due to groundwater withdrawal, to natural consolidation of alluvium soil and to the load of constructions. Land subsidence causes damages to infrastructure, buildings, and results in tides moving into low-lying areas. Up to the present, there has been no comprehensive information about the land subsidence and its monitoring in Semarang. This paper examines digital elevation model (DEM) and benchmark data in Geographic Information System (GIS) raster operation for the monitoring of the land subsidence in Semarang. This method will predict and quantify the extent of subsidence in future years. The future land subsidence prediction is generated from the expected future DEM in GIS environment using ILWIS package. The procedure is useful especially in areas with scarce data. The resulting maps designate the area of land subsidence that increases rapidly and it is predicted that in 2020, an area of 27.5 ha will be situated 1.5–2.0 m below sea level. This calculation is based on the assumption that the rate of land subsidence is linear and no action is taken to protect the area from subsidence.  相似文献   

泰州市地面沉降问题的探讨     

薛小平 《现代测绘》2006,29(2):26-27

通过两次测定的水准点高程数据的比较,评估出泰州市海陵区的地面沉降量,并由此进行了分析。对今后如何展开工作,重视地面沉降问题提出了重要的建议。  相似文献   

Failure mechanism in an extremely slow rock slide at Bitchu-Matsuyama castle site (Japan)   总被引：1，自引：1，他引：1  

Vladimir Greif  Kyoji Sassa  Hiroshi Fukuoka 《Landslides》2006,3(1):22-38

One of the specific problems related to historical structures is the fact that they are prone to damage caused by even very small deformations acting over a long period of time, such as creep or extremely small rock displacements. If any damage has already occurred, the determination of the rock slope failure mechanism is one of the prerequisites for successful mitigation technique selection. In this study a medieval castle in central Japan, suffering damage caused by deformation of the rock mass in the subgrade of the castle, was investigated using a combination of field investigation, high-precision monitoring and physical modeling experiments. Using these techniques an attempt to determine the failure mechanism of the rock slope was made. Based on the field investigation a toe-slope failure seemed to be the main triggering factor activating the deformations in the upper slope area, right below the defense walls of the castle. The displacement monitoring of the surface rock blocks revealed a slumping failure with the backward rotational component prevailing over the sliding in the immediate vicinity of the castle wall. This was in accordance with the expectations obtained from the structural analysis of the rock mass carried out during the field investigation. The displacements obtained during the rock block monitoring, especially from the crack gauges, were not sufficient for drawing a satisfactory conclusions about the failure mechanism of the blocks located in the central part of the slope. Therefore, the failure mechanisms of rock blocks inferred from their displacements obtained from the monitoring were correlated with the results of modeling experiments carried out on the scaled slope model. The physical modeling revealed a possibility of toppling failure of rock blocks in the central area of the slope caused mainly by block interlocking, which was supported by the data from surface tilt meters installed additionally in the field. Furthermore, the possibility of the occurrence of forward and backward rock block rotations in the same sliding body at given conditions was supported by the physical modeling experiments.  相似文献   

Application of multi-temporal differential interferometry to slope instability detection in urban/peri-urban areas     

F. Bovenga  R. Nutricato  A. Refice  J. Wasowski   《Engineering Geology》2006,88(3-4):218-239

We present two case studies regarding the application of Synthetic Aperture Radar (SAR) Persistent Scatterers Interferometry (PSI) techniques to landslide-prone slopes situated in the municipal territories of Caramanico Terme and Volturino (Italy). The analysis of satellite SAR data with PSI techniques poses often problems on sites where, due to the scarcity of human artefacts and the presence of vegetation cover, density of coherent points (PS) is low (< 10 per km²). Moreover, the steep and rough topography typical of landslide-prone areas hamper the interferometric pre-processing, making more difficult the joint estimation of displacements and of DEM errors. Under these conditions the significance of temporal interferometric phase trends can be uncertain and conservative assumptions, necessary to ensure low false detection probabilities, need to be coupled with innovative processing strategies to increase the detection efficiency of PS objects. Here, the SPINUA (Stable Point Interferometry over Un-urbanised Areas) processing technique is applied together with an alternative PS Candidate (PSC) selection procedure based on the use of pixels classified as urban.

The cases of Caramanico and Volturino are representative, respectively, of harsh and favourable conditions for PSI applications. The results from Caramanico show clusters of PS exhibiting similar line-of-sight (LOS) deformation behaviour in the period 1995–2000. The locations of moving PS often coincide with distressed buildings and appear consistent with the areal distribution of recent and past landslide activity. The temporal displacement trends, however, are characterised by very low annual average velocities (from 3 to 7 mm/y) and it is uncertain to what extent the PS data reflect true slope movements, local deformations (e.g. settlement of engineering structures) or both.

Thanks to the more favourable conditions, the application of the standard SPINUA approach in the Volturino area was sufficient to obtain suitable densities of PS, as well as spatially and temporally consistent displacement results for a period 1992–2000. In particular, a group of moving PS was identified in a peri-urban area, known for the past and recent slope stability problems. The slowly moving PS (from 3 to 5 mm/y) fall in a location that, unlike the remaining part of the town, is characterised by the presence of many distressed buildings and structures. Although the site information confirms the reliability of PS data, in the absence of ground monitoring and detailed records of landslide movements, it is difficult to identify the main mechanism of the detected deformations. In general, in geologically and topographically complex urban/peri-urban settings, the significance of very low-velocity PSI surface displacements should always be considered together with in situ geotechnical controls and ground monitoring data.  相似文献   

The Afternoon Creek rockslide near Newhalem, Washington   总被引：1，自引：0，他引：1  

A. Strouth  R. L. Burk  E. Eberhardt 《Landslides》2006,3(2):175-179

A series of mass wasting events occurred above a Washington, USA, highway in the Cascade Mountains in November and December 2003. The largest event was a rockslide involving approximately 750,000 m³ that occurred on November 9, 2003. The source zone for this event was located at the crest of a ridge. Most of the debris fell to the east of the sharp ridge and was deposited in the relatively shallow sloping Afternoon Creek without causing damage to the highway. Lesser amounts of debris fell to the west of the ridge, sliding 600 m down the steeper Falls Creek and impacting the road. There is an evidence of one or more historical rock avalanches at this location. Displacement of reference points, ground vibration, crack extension, and tilting are being monitored due to concerns that future slope failures or remobilization of debris might again damage or block the highway.  相似文献   

基于遥感技术的土地利用／覆被变化研究     

杜灵通 《国土资源信息化》2007,(2):18-22,27

遥感技术是研究土地利用/覆被变化状况的重要手段之一,目前该技术已有一套较成熟的研究方法,本文从遥感数据选择、图像预处理方法、土地利用/覆被变化遥感分类、土地利用/覆被变化动态信息提取等方面对土地利用/覆被变化遥感动态监测技术进行了系统的论述,最后指出多信息源、综合的信息处理机制将是土地利用/覆被变化遥感动态监测技术发展的必然方向。  相似文献   

Ferguson rock slide buries California State Highway near Yosemite National Park     

Edwin L. Harp  Mark E. Reid  Jonathan W. Godt  Jerome V. DeGraff  Alan J. Gallegos 《Landslides》2008,5(3):331-337

During spring 2006, talus from the toe area of a rock-block slide of about 800,000 m³ buried California State Highway 140, one of the main routes into heavily-visited Yosemite National Park, USA. Closure of the highway for 92 days caused business losses of about 4.8 million USD. The rock slide, composed of slate and phyllite, moved slowly downslope from April to June 2006, creating a fresh head scarp with 9–12 m of displacement. Movement of the main rock slide, a re-activation of an older slide, was triggered by an exceptionally wet spring 2006, following a very wet spring 2005. As of autumn 2006, most of the main slide appeared to be at rest, although rocks occasionally continued to fall from steep, fractured rock masses at the toe area of the slide. Future behavior of the slide is difficult to predict, but possible scenarios range from continued scattered rock fall to complete rapid failure of the entire mass. Although unlikely except under very destabilizing circumstances, a worst-case, rapid failure of the entire rock slide could extend across the Merced River, damming the river and creating a reservoir. As a temporary measure, traffic has been rerouted to the opposite side of the Merced River at about the same elevation as the buried section of Highway 140. A state-of-the-art monitoring system has been installed to detect movement in the steep talus slope, movement of the main slide mass, local strong ground motion from regional earthquakes, and sudden changes in stream levels, possibly indicating damming of the river by slide material.  相似文献