Study on electric variations of media in epicentral area by geomagnetic transfer functions

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岩溶在古地理研究中的作用——“关于古地理研究中若干原则问题的商榷”一文的补充及讨论

本文从现代、地史时期岩溶剥蚀速度及岩溶铝土矿的形成等方面探讨岩溶在古地理研究中的重大作用,从而提出稳定地区“缺失”某一时期地层,并非该时期为陆;而是前期仍有沉积,后期才真正上升为陆,遭受剥蚀。     

北京市地理国情监测外业调查与核查技术探讨

外业调查与核查是获取地理国情信息的重要手段,可帮助内业解译,更好地完成工作。本文介绍了北京市地理国情监测外业调查与核查工作的具体内容,从北京市实际需求出发,研究制定了一套面向北京市的地理国情监测外业调查与核查的技术方案,保证了北京市国家基础性监测和市情专题性监测的合理有效开展,为今后地理国情常态化监测外业工作的实施提供一定的技术参考。     

Mapping the crustal thickness in southwest Japan using Moho-reflected waves

In this work we have tried to detect and collect later phases associated with the Moho discontinuity and use them to study the lateral variations of the crustal thickness in southwest (SW) Japan. We first compute synthetic seismograms for local earthquakes taking into account the focal mechanism solutions estimated from first motion polarity data. Then we compare the synthetics with the observed waveforms to detect the major later phases in seismograms of shallow crustal earthquakes in SW Japan. Taking the advantage of the high quality and great quantity of Hi-net waveform data now available throughout the entire Japan Islands, we have detected 1659 Moho-reflected phases (PmP and SmS) from shallow events in SW Japan. We estimated the crustal thickness in the study area using travel time differences between these later phases and the first P and S arrivals. Our results show that the Moho is deep in Chubu district and becomes shallower along the coastlines of the Japan Sea and the Pacific Ocean. A thinner crust appears in Osaka Bay and Awajii Island where the 1995 Kobe earthquake (M7.2) occurred.     

青藏块体北缘跨断层测量资料宏观分析

本文在系统整理青藏块体北缘跨断层测量资料的基础上，进行了形变类型的划分，探讨了不同类型形变所反映的断层运动性能。     

利用树轮宽度重建黄河源区1618—2009年5—6月最高气温

利用采集自青海省雪山乡的祁连圆柏建立树轮宽度标准年表,将标准年表与黄河源区内4个气象站各气象要素作相关分析,结果显示整个源区5—6月最高气温与标准年表相关性最显著,相关系数为-0.65。根据相关分析结果,重建了黄河源区1618—2009年5—6月最高气温距平序列,重建方程经过逐一剔除检验,方差解释量达42.2%,具有一定的可靠性。重建序列在近400年间先后经历了8个较暖时间段和8个较冷时间段,暖期时段有1644—1656、1727—1746、1786—1797、1817—1835、1860—1885、1916—1934、1952—1968和1992—2005年,冷期的时段分别为1632—1643、1657—1696、1747—1764、1798—1816、1836—1859、1898—1915、1935—1951和1969—1991年。对比本次重建序列与杂多、青藏高原东部以及长江源的气温重建序列,发现以上序列在公共时段变化趋势一致,另外,一些文献和历史记载也证实了此次重建的可靠性。     

河南省耕地资源演变形式研究

着重从国家基建用地,集体建设用地,农民个人建房用地,农业结构用调地和灾害段地等多方面分析河南省耕地减少的原因,其目的是找出河南省耕地面积动态变化的特征,为今后保持耕地资源总量动态平衡,保证耕地有增无减以及为政府为耕地资源保护决策中提供科学依据。     

华北地区石炭－二叠系煤系地层和轻质油关系研究

对华北地区石炭－二叠系、下第三系、中上元古界沉积物和油样的低环萜烷参数用因子分析方法进行油源对比，表明石炭－二叠系部分样品与该区轻质油的关系密切。进一步分析这套地层的有机地球化学特征后，提出壳质组含量和成熟度是决定石炭－二叠系能否生成轻质油的主要因素，并提出该区煤系地层生成轻质油的成熟度下限是镜质组反射率Ｒ０为１．１％。     

Numerical simulation of fully saturated porous materials

Fully coupled, porous solid–fluid formulation, implementation and related modeling and simulation issues are presented in this work. To this end, coupled dynamic field equations with u?p?U formulation are used to simulate pore fluid and soil skeleton (elastic–plastic porous solid) responses. Present formulation allows, among other features, for water accelerations to be taken into account. This proves to be useful in modeling dynamic interaction of media of different stiffnesses (as in soil–foundation–structure interaction). Fluid compressibility is also explicitly taken into account, thus allowing excursions into modeling of limited cases of non‐saturated porous media. In addition to these features, present formulation and implementation models in a realistic way the physical damping, which dissipates energy. In particular, the velocity proportional damping is appropriately modeled and simulated by taking into account the interaction of pore fluid and solid skeleton. Similarly, the displacement proportional damping is physically modeled through elastic–plastic processes in soil skeleton. An advanced material model for sand is used in present work and is discussed at some length. Also explored in this paper are the verification and validation issues related to fully coupled modeling and simulations of porous media. Illustrative examples describing the dynamical behavior of porous media (saturated soils) are presented. The verified and validated methods and material models are used to predict the behavior of level and sloping grounds subjected to seismic shaking. Copyright © 2008 John Wiley & Sons, Ltd.