关于全国地震重点监视防御区制度实施现状、成效之调查、设计的说明

为评估全国地震重点监视防御区制度的实施现状、成效,课题组对相关问题进行了定性和定量研究,定量研究以系列问卷调查为主,包括政府、社区和公众问卷等。本文重点说明了系列问卷调查的设计、抽样以及回收情况,并对问卷调查发现的问题做了简单介绍。     

地震重点监视防御区县级行政单元地震危险性的差异统计及其分类管理的建议

本文利用GIS技术,将全国地震重点监视防御区(重防区)县级行政单元边界分别与中华人民共和国地震动峰值加速度图和中国及邻区地震区带和潜在震源区划分图叠加,对各县分别计算了如下4个地震危险性指标:(1)县境内最高地震动峰值加速度等级;(2)县境内面积比例最大的地震动峰值加速度等级;(3)县境内最高潜在震源区震级上限等级;(4)县境内面积比例最大的潜在震源区震级上限等级.通过分类统计全国重防区县级行政单元的地震危险性分布,得到的结论是:虽然同为重防区但各地的地震危险性相差巨大.据此,建议根据地震危险性的不同在重防区采取如下措施:第一,不论是何种类型的重防区,均应按中国地震动参数区划图对新建工程做抗震设防,对已有建筑做抗震加固;第二,位于高地震危险性的区域,特别是位于具7级以上潜在地震危险的重防区,要加强与防灾有关的应急准备、城市规划、地震监测预报、地震应急响应等专门措施.     

Seasonal variability of the carbon export in the central South China Sea

Ocean Dynamics - The South China Sea (SCS) is strongly influenced by the East Asian monsoon system with seasonal reversal. Measurements from a 7-year continuous sediment trap located in the central...     

大港油田三维可视化解释技术的应用实例分析

三维可视化解释技术是一项全新的地震解释技术,与传统的地震资料解释有着本质的不同,它是从三维可视化显示出发,以地质体或三维研究区块为单元,采用点、线、面和体相结合的数据体空间可视化解释。该技术结合相干体技术可进行复杂断层的解释与组合;应用空间域层位自动追踪技术能够准确落实构造形态;采用目标雕刻技术,利用反演数据体可实现立体透视岩性体的空间展布及厚度趋势。将该技术应用在大港油田官西地区复杂断块构造解释和歧南西斜坡隐蔽油气藏储层预测两项实际工作中,取得了良好效果,表明可视化解释技术在石油勘探中具有广阔的应用前景,是提高勘探效率和勘探成功率的有效技术手段。     

Implications of broad dose distributions obtained with the single-aliquot regenerative-dose method on quartz fine-grains from loess

Six samples were collected from a section of Peoria Loess in Eustis, North America, for optically stimulated luminescence (OSL) dating of quartz, and all except one (LV90) produced narrow dose distributions. A comparative study was conducted on this sample and on a ‘well-behaved’ sample (LV91), involving other dating methods and examination of the quartz OSL. These investigations revealed differences in the quartz OSL growth with dose, OSL response to thermal treatments and the range of components within the OSL signals. An ultra-fast component was found in LV90 that displayed a higher rate of sensitivity change than the fast component and this had a malign influence on the determination of the equivalent dose. The distinctive luminescence characteristics of LV90 imply either a change in wind dynamics and/or the source area for the silt.     

Effects of surface characteristics on infiltration patterns in an arid shrub desert

Precipitation is often the sole source of water replenishment in arid and semi‐arid areas and, thus, plays a pertinent role in sustaining desert ecosystems. Revegetation over 40 years using mainly Artemisia ordosica and Caragana korshinskii at Shapotou Desert Experimental Research Station near Lanzhou, China, has established a dwarf‐shrub and microbiotic soil crust cover on the stabilized sand dunes. The redistribution of infiltrated moisture through percolation, root extraction, and evapotranspiration pathways was investigated. Three sets of time‐domain reflectometry (TDR) probes were inserted horizontally at 5, 10, 15, 20, 30 and 40 cm depths below the ground surface in a soil pit. The three sets of TDR probes were installed in dwarf‐shrub sites of A. ordosica and C. korshinskii community with and without a microbiotic soil crust cover, and an additional set was placed in a bare sand dune area that had neither vegetation nor a microbiotic soil crust present. Volumetric soil moisture content was recorded at hourly intervals and used in the assessment of infiltration for the different surface covers. Infiltration varied greatly, from 7·5 cm to more than 45 cm, depending upon rainfall quantity and soil surface conditions. In the shrub community area without microbiotic soil crust cover, infiltration increased due to preferential flow associated with root tunnels. The microbiotic soil crust cover had a significant negative influence on the infiltration for small rainfall events (～10 mm), restricting the infiltration depth to less than 20 cm and increasing soil moisture content just beneath the soil profile of 10 cm, whereas it was not as strong or clear for larger rainfall events (～60 mm). For small rainfall events, the wetting front depth for the three kinds of surface cover was as follows: shrub community without microbiotic soil crust > bare area > shrub community with microbiotic soil crust. In contrast, for large rainfall events, infiltration was similar in shrub communities with and without microbiotic soil crust cover, but significantly higher than measured in the bare area. Soil water extraction by roots associated with evapotranspiration restricted the wetting front penetration after 1 to 3 h of rainfall. Copyright © 2006 John Wiley & Sons, Ltd.     

高压直流输电对泾县地震台地磁观测干扰分析

高压直流输电线路对地磁观测的干扰幅度大,随意性大.泾县地震台地磁观测目前受到附近穿行的多条高压直流输电影响,且无法避免.通过对泾县地震台观测资料分析,就高压直流输电对地磁观测的干扰原理和一些识别的方法有一定认识,并掌握有效剔除方法.     

Effets combinés de la pêche et de l'eutrophisation sur la perche (Perca fluviatilis L.) dans les eaux vaudoises du Léman

Catches of perch have strongly decreased in Lake of Geneva from 1975 to 1981. This decrease was attributed to the impact of overfishing, enhanced by the accelerated growth of perch. Therefore, too many perches were captured before their first reproduction and the stocks of reproducers were strongly reduced. Furthermore, adverse meteorological conditions occurred probably during several periods of reproduction. The accelerated growth of perch was attributed to the combined effects of increasing eutrophication (more food available) and of overfishing (decreased perch density in the shoals).      

环太平洋地震带与柯里奥利力

柯里奥利力是地球自转的一种惯性力，它使垂直下降的物体向东偏转，垂直上升的物体向西偏转，是形成环太平洋地震带中东西两岸构造应力差别的根本原因。