庐枞金属矿集区深地震反射剖面探测研究:一种经济的、变化的采集观测系统实验

如何运用深地震反射剖面技术同时探测大型金属矿集区浅自几百米,深至地壳底部的地壳精细结构,揭示成矿的深部过程,是一项极具挑战性的攻关实验内容。本文针对庐枞金属矿集区的浅深兼顾的探测目标,实验了一种区域长剖面和矿集区剖面结合的变观测系统采集技术。结果表明,区域长剖面使用40m道距,240m炮距,18～20m井深,16～20kg药量,中间放炮,720道双边接收,60次覆盖的采集参数能够获得浅层至Moho的有效反射,揭示出成矿区的深部构造。矿集区剖面加密道距至10m,炮距80m,将覆盖次数增加到90次,并采用十字测线的拟三维采集技术能有效补充获得丰富的矿区浅层信息,揭露出浅层控矿构造及其与深部的联系。在经费有限的前提下,采用上述变观测系统方法来保证获得浅、深多重反射信息的采集技术是可行的,实际结果证实了该方法技术实验的成功。     

Geographical analysis of damage due to flash floods in southern France: The cases of 12–13 November 1999 and 8–9 September 2002

The southern part of France near the Mediterranean Sea is subject to flash floods generated by heavy rainfalls typical of the Mediterranean climate. In November 1999 (the 12th and 13th) and in September 2002 (the 8th and 9th), 5000 km² were touched by rainfalls superior to 200 mm in the departments of Aude and Gard. In both cases, maximum precipitation exceeded 500 mm within 24 h. The damage amounted in the hundreds of millions of euros, and there were numerous fatalities: 35 in 1999, and 23 in 2002. Following a survey of available data, this article details the cost of the damage for both flash flood events. The distribution of the damage is quantified by sector of activity (e.g., industry, agriculture). The average ratio “euros of loss per inhabitant” is quite similar in both cases, but this average hides some geographical discrepancies. Losses in industry can locally worsen the overall toll. The mapping of damage on a local scale and the amount of losses per inhabitant demonstrate that rural areas underwent heavy losses. This was mostly due to the destruction of the public infrastructures (e.g., roads, bridges) that represented more than half of the overall loss. In some rural areas, the cost of flash floods can exceed 15,000 euros per inhabitant. Such flood prevention issues as flood warning systems and land use planning must not focus only on the cities. Death, injury and heavy material losses also disadvantage the rural and mountainous areas where populations and activities are concentrated near rivers.     

结构抗震技术经济投入产出效益分析的一种新指标

本文提出一种评估同一地区不同类型结构的抗震投入产出效益的新指标,即结构价值损失比率。利用"5·12"汶川地震后对甘肃陇南的学校、住宅、办公、医院和生命线工程等9类建筑物的调查统计结果,研究了震害等级、经济损失与结构抗震初始投入之间的关系,建立了结构价值损失比率与结构初始投入之间的关系和高烈度区危房率与地震地面运动峰值之间的关系。对比分析了土-木组合、砖-木组合、砖砌体结构、非隔震框架结构和基础隔震结构等不同类型结构的抗震性能,并与实际鉴定的震害等级相比较。利用结构价值损失比率,初步说明了采用隔震新技术结构的减灾效益。     

气象服务效益评估的两例实证及新的估测技术

通过实地调查，作者对气象服务行业经济效益与部门经济效益分别进行了实证，并在原有讨论的基础上提出了一种新的评估方法