对1668年8.5级大震震中的讨论

1668年7月25日,在郯城、莒县间发生8.5级强烈地震。有称莒县大震,有称郯城大震,有称临沂大震。因震中不确切,也有笼统称之为鲁南大震的。由于对这次大震震中位置说法不一,大震名称也就各异。确定震中,对研究震源机制,划分烈度等方面有其重要意义。同时对推测本区未来地震危险段,也有重要参考价值。因此,对1668年这次大震震中作深入探讨很有必要。     

ENSO和长江大水对天文因子的响应研究

ENSO（厄尔尼诺和南方涛动的总称）对世界尺度的天气气候有影响,本文用概率论统计检验方法,查明长江大水与ENSO以及ENSO与天文因子的相关关系,并系统分析了三者之间的相关关系。结果表明:ENSO事件对天文物理主周期和天文特征有明显的响应,长江大水年对太阳活动特征、节气日的月相年变化和ENSO也有显著的响应关系。这些关系对长江大水的准确预测有重要价值。文中对天文物理因子对ENSO和大水的影响机理进行了探讨。     

锚杆加固对石窟地震反应的影响

利用大型通用AD INA有限元分析软件进行动力分析,研究锚杆加固对石窟地震反应的影响。通过对无裂隙无锚杆、有裂隙无锚杆、有裂隙有锚杆和有裂隙有预应力锚杆4种模型的分析,研究了锚杆在石窟岩体加固中的作用。结果表明,锚杆的加固作用是明显的,在有裂隙的部位打入锚杆对石窟整体结构的安全性是有益处的。通过两条地震波作用下石窟的地震反应分析,指出了石窟结构在地震荷载作用下的薄弱部位,计算结果表明地震作用下薄弱部位多数发生在石窟的脚点附近,分析结果可作为石窟抗震设计的参考依据。     

龙滩水电站区域构造稳定性及诱发地震地质条件的探讨

本文对北西向的望谟—逻西—八南断裂带作了较详细的研究,其东南段在大坝西侧库内十余公里处通过,有6级地震的危险性,对大坝约有V11度的影响;库外紧邻大坝的天峨背斜东西两侧发育的断裂带,自上新世—早更新世以后无明显活动迹象;库域东南侧有一个断裂闭锁区,有发生中强地震的可能性,对大坝有一定的影响,库域北缘之弧形构造对大坝基本无影响。可能诱震的主要构造有:望谟一逻西一八南断裂带的东南段与西北段,库域区北缘的弧形构造。此外,库域区东南侧之更新库段,也可能因蓄水而诱震。     

内罐影响下LNG储罐外罐地震响应分析

为了考虑内罐在不同方向地震动时对LNG(液化天然气)储罐外罐的影响,对有内罐和无内罐情况下LNG储罐外罐进行了地震响应分析。结果表明:有内罐时地震响应比无内罐时小,内罐的存在对LNG储罐抗震有好的影响;竖向地震波对结构振动的影响不能忽视。     

喀左地震台土体地应力观测映震效能分析

本文通过整理喀左地震台地应力观测资料,并结合历史震例,对发生地震的时间、方位、震级与喀左地震台地应力异常特征的关系作出初步分析判断,认为喀左地震台土体应力观测对辽西及周边地区小震及中强震有很好的异常反应,有较好的映震效能,并对东北地区尤其是吉林深震有一定的异常显示。     

2D电阻率正反演成像在水平和垂直模型上的异常响应研究

2D电阻率成像技术近年来被广泛应用于工程、水文、环境和矿产等领域,在实际应用中它具有多种的装置类型,不同的装置类型对特定的地质情况有不同的应用效果.本文通过采用Wenner、Wenner-Schlumberger和dipole-dipole三种排列装置在一个水平和一个垂直模型上正演模拟和块反演,揭示了不同的排列装置在水平结构和垂直结构的异常响应,并对高阻体和低阻体进行了模拟.结果显示当采用Wenner,Wenner-Schlumberger和dipole-dipole数据采集技术时,不同的模型结构异常响应有明显的不同,三种排列类型对地下低阻体的分辨能力均高于高阻体,Wenner装置和dipole-dipole装置分别对水平层状结构和垂直结构有较好的分辨力,wenner-Schlumberger装置对水平层状结构有好的分辨力,对垂直结构有中等的分辨能力.     

隆尧5.8级地震的地电阻率异常

本文对1981年11月9日隆尧5.8级地震前后,周围70千米范围内三个地电台资料的分析,得出三个台电阻率震前有下降的短期异常,临震前二个台电阻率有加速下降现象.这种变化对探索研究地震预报是有现实意义的.     

有壳变形虫群落组成及与环境因子的关系——以山西滹沱河湿地为例

滹沱河湿地是山西省重要的湿地资源,对生物多样性的保护有至关重要的作用.有壳变形虫是一类生活在淡水生态系统中的原生动物,对环境变化响应敏感,是良好的环境生物指示剂.本研究主要对山西滹沱河流域6个湿地52个不同生境的沉积样品进行有壳变形虫物种组成及多样性分析,通过对有壳变形虫和环境因子数据进行排序分析探讨影响有壳变形虫群落分布的关键环境因子.结果显示:滹沱河湿地共记录有壳变形虫20种,其中斜口三足虫(Trinema enchelys)、顶足法帽虫(Phryganella acropodia)和线条三足虫(Trinema lineare)为优势种,相对丰度分别为23.4%、17.38%、13.48%.沉积物粒度和有机质含量对有壳变形虫的物种组成及多样性有显著影响,砂粒含量越低、有机质含量越高,有壳变形虫的丰富度和多样性就越高.CCA排序结果表明硝态氮和COD是影响有壳变形虫种类组成和分布的关键环境因子,解释量分别为19.6%和17.3%,而pH的解释量最小,为8.6%.本研究结果为山西湿地有壳变形虫的现代生态学研究提供借鉴,为湿地多样性保护、管理和修复提供理论支撑.     

龙门山地区历史强震数值模拟

考虑区域地质构造差异、主要活动断裂分布特征和地表附加重力影响,建立反映龙门山地区地表起伏和岩石圈分层的三维粘弹性有限元模型。以GPS为约束重建研究区现今构造应力场,依次模拟龙门山地区1900年以来发生的5次M_S 7.0以上地震,从库仑应力和等效应力角度,分析应力场演化对强震的影响以及强震间的相互作用关系。研究结果表明:从库仑应力角度,有3次地震对后续地震有促进作用,其中汶川地震对芦山地震有触发作用;从等效应力角度,有4次地震对后续地震的发生具有加速作用。     

Impact of climate change on diffuse pollutant fluxes at the watershed scale

This study aims to assess watershed‐scale impacts of changing climate on sediment, phosphorus, nitrogen and pesticide (atrazine) fluxes over the 21st century at the watershed scale. In particular, changes in dissolved and particulate forms of water quality constituents in response to climate change are investigated. The hydrologic model Soil and Water Assessment Tool was calibrated and evaluated in a primarily agricultural watershed in the Midwestern United States to simulate hydrologic and water quality processes on a daily basis over the 2015–2099 time horizon. The model was then driven with 112 distinct statistically downscaled climate projections representing Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) low, moderate and high greenhouse gas emission scenarios. Projected hydrologic and water quality responses were categorized according to the three IPCC SRES emission scenarios for summarizing and synthesizing results over early‐century (2015–2034), mid‐century (2045–2064) and late‐century (2080–2099) assessment. Results revealed clear warming trends in the study area, whereas small increases in precipitation were predicted. Streamflow, sediment and total nutrient loads did not differ noticeably between assessment periods. However, the proportion of dissolved to total nutrients increased significantly from early‐century to late‐century periods. With the exception of total atrazine in the mid‐century period, predicted pollutant loads for a given assessment period did not differ between emission pathways for a given assessment period. Changes in pollutant fluxes showed pronounced monthly variability. The projected increase in readily available forms of nutrients has important implications for the ecological health of water systems and management of drinking water supplies. Copyright © 2013 John Wiley & Sons, Ltd.     

Prediction of carbon exchanges between China terrestrial ecosystem and atmosphere in 21st century

The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interaction model (AVIM2). The results show that in the coming 100 a, for SRES B2 scenario and constant atmospheric CO2 concentration, the net primary productivity (NPP) of terrestrial ecosystem in China will be decreased slowly, and vegetation and soil carbon storage as well as net ecosystem productivity (NEP) will also be decreased. The carbon sink for China terrestrial ecosystem in the beginning of the 20th century will become totally a carbon source by the year of 2020, while for B2 scenario and changing atmospheric CO2 concentration, NPP for China will increase continuously from 2.94 GtC·a?1 by the end of the 20th century to 3.99 GtC·a?1 by the end of the 21st century, and vegetation and soil carbon storage will increase to 110.3 GtC. NEP in China will keep rising during the first and middle periods of the 21st century, and reach the peak around 2050s, then will decrease gradually and approach to zero by the end of the 21st century.     

Operation of two major reservoirs of Iran under IPCC scenarios during the XXI century

We assess the effects of prospective climate change until 2100 on water management of two major reservoirs of Iran, namely, Dez (3.34 × 10⁹ m³) and Alavian (6 × 10⁷ m³). We tune the Poly‐Hydro model suited for simulation of hydrological cycle in high altitude snow‐fed catchments. We assess optimal operation rules (ORs) for the reservoirs using three algorithms under dynamic and static operation and linear and non‐linear decision rules during control run (1990–2010 for Dez and 2000–2010 for Alavian). We use projected climate scenarios (plus statistical downscaling) from three general circulation models, EC‐Earth, CCSM4, and ECHAM6, and three emission scenarios, or representative concentration pathways (RCPs), RCP2.6, RCP4.5, and RCP8.5, for a grand total of nine scenarios, to mimic evolution of the hydrological cycle under future climate until 2100. We subsequently test the ORs under the future hydrological scenarios (at half century and end of century) and the need for reoptimization. Poly‐Hydro model when benchmarked against historical data well mimics the hydrological budget of both catchments, including the main processes of evapotranspiration and streamflows. Teaching–learning‐based optimization delivers the best performance in both reservoirs according to objective scores and is used for future operation. Our projections in Dez catchment depict decreased precipitation along the XXI century, with ?1% on average (of the nine scenarios) at half century and ?6% at the end of century, with changes in streamflows on average ?7% yearly and ?13% yearly, respectively. In Alavian, precipitation would decrease by ?10% on average at half century and ?13% at the end of century, with streamflows ?14% yearly and ?18% yearly, respectively. Under the projected future hydrology, reservoirs' operation would provide lower performance (i.e., larger lack of water) than now, especially for Alavian dam. Our results provide evidence of potentially decreasing water availability and less effective water management in water stressed areas like Northern Iran here during this century.     

Pressure effects on regional mean sea level trends in the German Bight in the twenty-first century

The effect of large-scale atmospheric pressure changes on regional mean sea level projections in the German Bight in the twenty-first century are considered. A developed statistical model is applied to climate model data of sea level pressure for the twenty-first century to assess the potential contribution of large-scale atmospheric changes to future sea level changes in the German Bight. Using 78 experiments, an ensemble mean of 1.4-cm rise in regional mean sea level is estimated until the end of the twenty-first century. Changes are somewhat higher for realisations of the special report on emission scenarios (SRES) A1B and A2, but generally do not exceed a few centimeters. This is considerably smaller than the changes expected from steric and self-gravitational effects. Large-scale changes in sea level pressure are thus not expected to provide a substantial contribution to twenty-first century sea level changes in the German Bight.     

应力触发模型研究进展概述

对应力触发问题的研究从20世纪60年代至今已近半个世纪。这半个世纪以来,地震专家和学者通过对大量震例的分析和比较,在应力触发问题某些方面的研究逐渐从探索性趋向系统性。主要从静态库仑破裂应力、动态库仑破裂应力和完整库仑破裂应力3方面简要概述其对地震触发的作用。     

Earthquake resistant construction techniques and materials on Byzantine monuments in Kiev

The study of the behaviour of historic buildings that have suffered from earthquakes has become a valuable tool for the understanding of earthquake resistant construction techniques and materials. Byzantine monuments of the 11–13th century in Kiev have been studied to provide insights into their effective dynamic properties facing severe earthquake history in the area. The recessed brickworks according to the “concealed course” construction technique of the St. Sophia Cathedral (11th century), the Church of St. Michael in the Vydubytskyi Monastery (11th century), the Tithe Church of the Assumption of the Virgin (10th century) and the Cathedral of Assumption of the Virgin (11th century) in the Monastery of the Caves (Pecherskyi monastery) in Kiev were studied and the material properties of bricks and lime mortars with ceramic fill were investigated (mechanical strength tests, mineralogical, chemical and microstructural analysis). The results show major similarities with those of the Byzantine monuments in Istanbul (Theodosian Walls and Hagia Sophia — 6–11th century construction phases), giving evidence of earthquake resistant construction techniques and materials allowing for continuous stresses and strains. Hence, didactics on proper restoration techniques and materials are deduced aiming at their present safety in the face of future earthquakes.     

Large-Scale Surface Mass Balance of Ice Sheets from a Comprehensive Atmospheric Model

The surface mass balance for Greenland and Antarctica has been calculated using model data from an AMIP-type experiment for the period 1979?C2001 using the ECHAM5 spectral transform model at different triangular truncations. There is a significant reduction in the calculated ablation for the highest model resolution, T319 with an equivalent grid distance of ca 40?km. As a consequence the T319 model has a positive surface mass balance for both ice sheets during the period. For Greenland, the models at lower resolution, T106 and T63, on the other hand, have a much stronger ablation leading to a negative surface mass balance. Calculations have also been undertaken for a climate change experiment using the IPCC scenario A1B, with a T213 resolution (corresponding to a grid distance of some 60?km) and comparing two 30-year periods from the end of the twentieth century and the end of the twenty-first century, respectively. For Greenland there is change of 495?km³/year, going from a positive to a negative surface mass balance corresponding to a sea level rise of 1.4?mm/year. For Antarctica there is an increase in the positive surface mass balance of 285?km³/year corresponding to a sea level fall by 0.8?mm/year. The surface mass balance changes of the two ice sheets lead to a sea level rise of 7?cm at the end of this century compared to end of the twentieth century. Other possible mass losses such as due to changes in the calving of icebergs are not considered. It appears that such changes must increase significantly, and several times more than the surface mass balance changes, if the ice sheets are to make a major contribution to sea level rise this century. The model calculations indicate large inter-annual variations in all relevant parameters making it impossible to identify robust trends from the examined periods at the end of the twentieth century. The calculated inter-annual variations are similar in magnitude to observations. The 30-year trend in SMB at the end of the twenty-first century is significant. The increase in precipitation on the ice sheets follows closely the Clausius-Clapeyron relation and is the main reason for the increase in the surface mass balance of Antarctica. On Greenland precipitation in the form of snow is gradually starting to decrease and cannot compensate for the increase in ablation. Another factor is the proportionally higher temperature increase on Greenland leading to a larger ablation. It follows that a modest increase in temperature will not be sufficient to compensate for the increase in accumulation, but this will change when temperature increases go beyond any critical limit. Calculations show that such a limit for Greenland might well be passed during this century. For Antarctica this will take much longer and probably well into following centuries.     

我国大地电磁测深新进展及瞻望

简要回顾了上世纪60－80年代，我国大地电磁测深工作的起步和发展， 较全面地介绍了90年代以来的新进展，并瞻望了新世纪的发展方向。     

全球变暖背景下东亚气候变化的最新情景预测

在最新的SRES A2和B2温室气体排放情景下,利用国际上7个气候模式针对未来全球变暖的数值模拟结果,本文着重分析了东亚区域气候21世纪的变化趋势. 研究揭示：中国大陆年均表面气温升高过程与全球同步,但增幅在东北、西部和华中地区较大,且表现出明显的年际变化;全球年均表面气温增幅纬向上大体呈带状分布,两极地区最为明显,并在北极地区达到最大;此外,21世纪后半段北半球高纬度地区的年平均强升温幅度主要来自于冬季增温. 在21世纪前50年,温室气体含量的增加除在一定程度上会增加青藏高原大部分夏季降水量外,不会对中国大陆其余地区的年、季节平均降水量产生较大影响;但持续的温室气体含量增加将最终导致大陆降水量几乎是全域性的增加.