对由制定抗震救灾工作预案引起地震误传的平息与启示

本文概述了在制定和部署抗震救灾工作预案时，所引起地震误传事件的经过、对社会造成的影响，以及采取的对策和所汲取的教训。     

Morphologic development, relative sea level rise and sustainable management of water and sediment in the Ebre Delta, Spain

The Ebre (Ebro) Delta is one of the most important wetland areas in the western Mediterranean. Ca. 40 % of the delta plain is less than 0.5 m above mean sea level and part of the southern margin of the delta is at mean sea level in an area protected by dikes. Both mean rates of secular subsidence in the Ebre Delta and eustatic sea level rise are ca. 1 – 2 mm/yr. Thus, the present annual relative sea level rise (RSLR) rate in the Ebre Delta may be at least 3 mm/yr. Measured accretion rates in the delta range from 4 mm/yr in the wetlands surrounding the river mouth to <0.1 mm/yr in impounded salt marshes and rice fields. The annual sediment deficit in the delta plain to offset RSLR is close to 1 million m³/yr. Accretion rates in the rice fields prior to the construction of large dams in the Ebre watershed were higher than RSLR rates, from 3 – 15 mm/yr. At present, >99 % of the riverine sediments are retained in the reservoirs and rice fields are losing ca. 0.2 mm/yr. Future management plans should take RSLR into account and include control of freshwater and sediment flows from the river in order to offset negative effects from waterlogging and salt intrusion, and maintain land elevation. This will include the partial removal of sediments trapped behind the Ribarroja and Mequinença dams. Stocks and inputs of sediments in the corresponding reservoirs are large enough for land elevation of ca. 50 cm in the whole delta plain. Advantages of this solution include (1) new sediments to the delta to offset subsidence (via rice fields) and coastal retreat, (2) enhanced functioning of the delta (productivity and nutrient processing), (3) avoidance of accumulation of sediments in the reservoirs. Hence, it is important to manage river discharges at the dams from an integrated viewpoint, whereas currently only hydropower and agricultural requirements are considered. It is also crucial to maintain periods of high discharge, to have enough river energy to transport as much sediments as possible.     

Assessing wetland changes in the venice lagoon by means of satellite remote sensing data

Not only does lagoon ecology represent a transitional zone between the sea and the continent but it also expresses the equilibrium belt between erosion and sedimentation processes. Within the framework of a coastal management scheme, a precise and timely mapping of morphological changes in this environment is important. This paper illustrates the possible contribution of multi-temporal satellite observations in the monitoring of the erosion/sedimentation processes of coastal zones, where landscape features are subjected to highly morphodynamical modifications. In particular, an improved mapping accuracy was obtained by the successive application of the Maximum Likelihood (MLH) classifier and the Linear Mixture Model (LMM) techniques to the satellite image classification procedure. In fact, by estimating the amount of shallow water and wetland within each satellite pixel, the LMM technique allows for an accurate mapping of the transitional zones in the lagoon environment, thus permitting an optimal separation between land and water. The study concerns the Venice lagoon (Italy) which has been sinking slowly since the beginning of this century. This has led to widespread loss of wetlands. In order to monitor the development of the land cover, four Landsat Thematic Mapper scenes were examined, during the period 1984 to 1993. The results obtained proved that the digital analysis method of multitemporal satellite imagery, applied over a selected test area, enables the evolution of an estuarine environment landscape, with its different sequences of erosion and periods of accretion, to be monitored. The significant influence of tidal stages is discussed in the data analysis.     

基于RS/GIS技术的南四湖流域典型市域生态敏感性评价——以济宁市为例

基于RS和GIS技术,利用多源数据,从土壤侵蚀、土壤盐渍化、景观以及采矿塌陷4个方面对研究区的生态敏感性进行了评价,研究了空间分布差异及规律。结果表明:土壤侵蚀敏感性以轻度和中度为主,由东北和西南向中心递减趋势;土壤盐渍化除西部平原区盐渍化高风险突出外,敏感性普遍较低,由西向东递减;景观稳定性主要表现为轻度敏感,由四周向中心递减;采矿塌陷敏感性指标由于受人类活动影响呈现极端分布,高敏感区主要分布在研究区中部地区;研究综合生态敏感性分布空间差异显著,以不敏感区为主,整体上呈由西向东递减的趋势。     

淮南潘北矿塌陷湿地土壤退化评价

采煤带来的地面塌陷是极为重要的新生环境地质问题。以淮南潘北矿塌陷湿地为研究区域,其总氮(TN)含量平均水平为1.04g/kg,总磷(TP)含量平均水平为425mg/kg,在空间分布上均有从非季节性积水区向季节性积水区递减的趋势。土壤理化性质指标间总氮与有机质(SOM)含量呈极显著正向相关,与pH呈负向相关,与有效磷(AP)呈正向相关;总磷与有效磷表现为极显著相关;AP与有效钾(AK)、SOM都有很好的相关关系。通过应用相关分析和模糊数学的原理,以TN、TP、AP、AK和SOM等5个土壤肥力指标为基础,对该区域季节性积水区和非积水区土壤肥力进行数值化综合评价。季节性积水区IFI为0.463,非积水区IFI为 0.601,表明塌陷湿地形成后会加剧水域周边土壤的退化。     

煤矿区采煤沉陷灾害分析与对策研究

煤矿区采煤沉陷问题,目前已引起世界各产煤国的普遍重视。我国因农村人口稠密,所以采煤沉陷的危害更为严重。本文全面系统地分析了采煤沉陷在地表可能造成的各种危害,并以减轻危害程度为目标,提出了开采前和开采过程中的预防措施,以及采后地面沉陷的治理措施。     

岸坡侵蚀及其防治

岸坡侵蚀是土地侵蚀的一个类型．它进一步又可划分为岸坡崩塌、滑坡侵蚀，岸坡塌陷侵蚀，岸坡沟谷侵蚀和岸坡洪水侵蚀。本文在详细分析各类岸坡侵蚀的基础上，提出了岸坡侵蚀的特点和防治对策。     

注浆减沉机理的新认识和注浆系统可靠度分析

笔者通过对影响注浆减沉技术效果的分析 ,建立了由浆体单元、钻孔单元、围岩体单元和封孔单元组成子系统的注浆减沉系统 ,以及系统对应的可靠度分析模型 ;运用可靠度理论 ,解析并得出了注浆减沉系统可靠度计算公式 ;依据建立的注浆减沉系统模型 ,借助数理统计和随机过程等工具 ,可以做到比较准确地预测注浆减沉的效果 ,优化注浆参数和改善注浆工艺 ,为减少地下工程开挖损害 ,保护环境和施工安全提供了新的途径。     

鄂尔多斯采煤损毁土地预测与复垦模式分析

鄂尔多斯地区作为我国的主要储煤区,由于煤炭开采导致的土地损毁问题日趋严峻,探索适宜该区自然条件特点的采煤沉陷损毁规律与土地复垦模式,对于该区土地资源可持续发展具有重要的现实意义。在对生产工艺、土地利用现状分析的基础上,采用MSPS软件对项目区采煤沉陷土地进行损毁范围及程度分析,进而结合损毁预测结果制定复垦措施:对耕地区因地制宜进行梯田整地、灌溉、排水设施建设,林、草地区在尽量减少地表扰动的前提下适时补植,并加强管护。     

Recent Change in the Extent of Mangroves in the Northern Gulf of Papua,Papua New Guinea

Existing at the interface of land and sea, in regions of low topographic relief, mangroves are likely to be some of the first ecosystems that undergo spatial modification due to sea-level rise. The mangrove ecosystems of the Gulf of Papua New Guinea are some of the largest and most pristine in the Asia–Pacific region; they have not been subject to clearance for crustacean farming nor suffered from land reclamation projects. This article establishes through analysis of a time series of aerial photography and satellite imagery from the period 1973–2007, that there have been substantial changes in the distribution of mangroves in this region. These changes include the seaward progradation of the Purari Delta and the regression of the Kikori Delta by an average of 43 m year⁻¹ at its most seaward point. While these findings are likely to be continuations of long-term trends, it is probable that they can be explained by a variety of interacting factors including climate change, sea-level rise, subsistence in the northern Gulf of Papua and changes in sediment dynamics.