南海磁场特征研究

建立客观的磁力ΔT异常,获得可信的磁力ΔZ_⊥异常、居里面成果, 在此基础上开展综合地质地球物理研究,对于解决南海资源等相关的地质、地球物理问题意义重大.本文汇集我国历年在南海取得的磁力实测资料,重新处理、校正、整合,特别是追溯南海周边的国际地磁台的日变资料进行日变改正,形成的南海磁力ΔT异常,其资料品质得到了极大提高.采用全磁纬变倾角化极技术,获得磁力ΔZ_⊥异常,其与实测证实的磁性海山、海岛有非常好的匹配关系,建立起可以直接用于反演处理解释的南海磁力ΔZ_⊥异常.选择磁力ΔZ_⊥异常的小波多尺度分解四阶逼近,采用单一磁性界面反演技术进行深度反演,获得居里面又称磁性底界面.建立了认识、解释南海的磁场基础体系,证实了南海基性岩浆岩分布区与磁力ΔZ_⊥异常的正磁异常高密切相关,区域性的磁力ΔZ_⊥异常负磁异常区可能与居里面深度相关.     

南华北地区地震活动特征分析

南华北盆地与秦岭大别造山带在构造上有耦合关系,地震活动水平相当。将南华北盆地和秦岭大别造山带组成的南华北地区作为研究对象,考察了其地震活动特征和青藏高原强震对其影响作用。发现南华北地区地震活动水平显著低于北华北地区,略低于下扬子地区。并且,通过对比分析青藏块体7.0级以上地震和南华北地区4.0级以上地震的对应关系,发现两个地区之间存在明显的成组对应现象,并表现2年左右的时间差,表明青藏块体的地震活动对南华北地区有明显的构造应力场传递作用。该结果为南华北地区中长期地震预测提供依据。2017年四川阿坝州九寨沟县发生7.0级地震,根据时间延迟的存在,对南华北地区未来中等地震的发生具有一定的指示意义。     

冬季亚洲中强震与夏季我国东部主雨带的准同纬性

根据1954～2003年50年亚洲中强震与我国地温资料,分析了冬季震中纬度—震涡中心纬度—冬季我国东部强地热涡中心纬度—夏季我国东部主雨带纬度4者之间的相互关系,发现冬季中强震与夏季主雨带之间具有较好的准同纬性. 这是每年汛期降水预报的一个指标. 文中也讨论了应用此预报指标时的一些特例.     

Modeling the climatic effects of the land use/cover change in eastern China

This study aims to quantify the contribution of land use/cover change (LUCC) during the last three decades to climate change conditions in eastern China. The effects of farmland expansion in Northeast China, grassland degradation in Northwest China, and deforestation in South China were simulated using the Weather Research and Forecasting (WRF) model in addition to the latest actual land cover datasets. The simulated results show that when forestland is converted to farmland, the air temperature decreased owing to an increase in surface albedo in Northeast China. The climatic effect of grassland degradation on the Loess Plateau was insignificant because of the negligible difference in albedo between grassland and cropland. In South China, deforestation generally led to a decrease in temperature. Furthermore, the temperature decrease caused by the increase in albedo counteracted the warming effects of the evapotranspiration decrease, so the summer temperature change was not significant in South China. Excluding the effects of urbanization in the North China Plain, the LUCC effects across the entire region of East China presented an overall cooling trend. However, the variation in temperature scale and magnitude was less in summer than that in winter. This result is due mainly to the cooling caused by the increase in albedo offset partly by the increase in temperature caused by the decrease in evaporation in summer. Summer precipitation showed a trend of increasing–decreasing–increasing from southeast to northwest after LUCC, which was induced mainly by the decrease in surface roughness and cyclone circulations appearing northwest of Northeast China, in the middle of the Loess Plateau, and in Yunnan province at 700 hPa after forests were converted into farmland. All results will be instructive for understanding the influence of LUCC on regional climate and future land planning in practice.     

Characteristics of Horizontal Crustal Movement in the North China Region in the Last Decade

Based on high-precision data obtained in the past decade from GPS re-measurement in the North China Network, the Crustal Movement Observation Network of China (CMONOC) and GPS measurement along the Shanxi graben zone, the status and evolution of horizontal crustal movement in the North China region are analyzed. The results show that (1) the Yanshan tectonic zone (Zhangjiakou-Bohai Sea zone)is an active one with the largest horizontal strain in the North China region; The largest tendency differential movement of adjacent blocks is seen between the Yanshan block and the North China plain block; about 2mm/a (left lateral) ; (2)The significant horizontal differential movement along the boundaries of the North China region is characterized by right-lateral strike-slip movement at the middle-north segment on its west boundary (composed of Yinchuan and other active tectonic zones) and compressive movement at the south segment; while the Yinshan rift zone located along the west segment on its north boundary is dominated by tensile movement. Other boundaries and zones have no obvious differential movement; (3) On the whole, measurements of each period differ from one another, which might result from the nonlinear movement component as well as from the error effect. In the paper, results of the relative movement and strain in different periods are given for different blocks and boundary zones.     

南海北部陆坡区多次波发育特征及压制策略分析

南海北部陆坡坡折带和常规海上地震勘探观测系统的制约,再加上南海北部陆坡区复杂的海底地层构造,导致南海北部陆坡区地震勘探成像结果不够理想.究其主要原因是多次波发育复杂、遮挡了一次波能量,也就直接影响到一次波的成像效果,从而制约了对陆坡区更深入的油气勘探.本文结合南海北部陆坡区的构造特征,依据多次波的产生机理分析多次波的发育分布状况,得出单一的地球物理方法已经不能较好的解决南海北部陆坡区的多次波压制问题.针对该区域复杂的地质背景,在综合运用多种地球物理方法的基础上,严格依照多区域、多尺度的理念,提出一套适应南海北部陆坡区多次波压制的系统策略.经过实际资料检验,有效的压制南海北部陆坡区的多次波干扰,最大程度的突出一次波成像,为南海北部进一步的油气勘探夯实基础.     

Decline in the species richness contribution of Echinodermata to the macrobenthos in the shelf seas of China

Echinoderms play crucial roles in the structure of marine macrobenthic communities. They are sensitive to excess absorption of CO₂ by the ocean, which induces ocean acidification and ocean warming. In the shelf seas of China, the mean sea surface temperature has a faster warming rate compared with the mean rate of the global ocean, and the apparent decrease in pH is due not only to the increased CO₂ absorption in seawater, but also eutrophication. However, little is known about the associated changes in the diversity of echinoderms and their roles in macrobenthic communities in the seas of China. In this study, we conducted a meta-analysis of 77 case studies in 51 papers to examine the changes in the contribution of echinoderm species richness to the macrobenthos in the shelf seas of China since the 1980s. The relative species richness (RSR) was considered as the metric to evaluate these changes. Trends analysis revealed significant declines in RSR in the shelf seas of China, the Yellow Sea, and the East China Sea from 1997 to 2009. Compared with the RSR before 1997, no significant changes in mean RSR were found after 1997, except in the Bohai Sea. In addition, relative change in the RSR of echinoderms and species richness of macrobenthos led to more changes (decrease or increase) in their respective biomasses. Our results imply that changes in species richness may alter the macrobenthic productivity of the marine benthic ecosystem.     

2000年中国地区地磁场长期变化的区域特征

本文用中国地磁场复测点和地磁台站资料,建立了2000年代中国参考地磁场长期变化模型CGRF-SV2000.模型显示,中国地区地磁场变化比较平缓,X、Y、Z、H、D、I、F七个地磁要素的“无符号平均年变率”分别为122 nT/a、82 nT/a、438 nT/a、118 nT/a、096(′)/a、299(′)/a、224 nT/a,比国际参考地磁场IGRF给出的全球年变率约小1/3到1/2.各地磁要素的变化显示,地磁北极正在向中国移近,或者说,中国正在向高地磁纬度方向移动,平均移动速度约为3(′)/a.磁偏角变化还显示,中国地区东西部偏角差异继续扩大.作为检验和对比研究,本文利用第8代国际参考地磁场（IGRF）模型,分析了全球地磁场长期变化的时空特征,讨论了全球长期变模型IGRF_SV与中国长期变模型CGRF_SV的异同点.对比分析表明,中国地区地磁场的长期变化与全球长期变化总趋势基本符合,但是,CGRF_SV也表现出一些特有的局部异常特征.     

南海前新生代残留盆地分布综合地球物理研究

为了对南海海域的前新生代残留盆地分布有个整体而全面的认识,本文开展了南海残留盆地宏观分布的综合地球物理研究.通过岩石物性分析,综合重、磁、震等地球物理方法,利用正演与反演方法,分区计算并求取了南海的重力基底和磁性基底埋深,得到了中生界及前中生界残余厚度,给出了整个南海前新生代残留盆地的宏观格架与残余厚度分布特征并讨论了...     

青藏高原对华北地区地震活动影响的统计学证据

基于中国各构造区1900年以来的本尼奥夫应变累积释放序列,采用协整分析和因果关系检验方法研究表明,青藏高原与华北地区地震活动的应变释放存在着长期均衡关系;在某种程度上,青藏高原地区地震应变释放是华北地区应变释放发生变化的原因;青藏高原对华北地区地震应变释放的影响存在约20多年的滞后效应.本文结果对两个构造单元的地球动力学研究提供了统计学证据.     

二次创业与南方海相碳酸盐岩油气勘探的发现与展望

本文概述了中国南方碳酸盐岩地区的油气勘探经历和认识过程.在刘光鼎院士提出的"油气资源二次创业"理论方法指导下,我国在海相碳酸盐岩地区开展的地球物理勘探工作取得了重要成果.海相碳酸盐岩地区具有更复杂的地质构造和演化过程,该类地区寻找油气是世界性难题,传统勘探手段已不适用.本文给出了该类地区进行地球物理勘探的新思路、新方法、新技术,并以举世瞻目的普光大气田的发现说明了新方法的合理性和优势.文章最后给出在南方海相碳酸盐岩地区进行油气地球物理勘探的发展远景.     

马尼拉俯冲带缺失中深源地震成因初探

马尼拉俯冲带是整个南海地震活动多发区,地震成因与南海的形成和构造演化关系密切.对马尼拉俯冲带地震数据和层析成像结果进行了深入分析.结果表明:马尼拉俯冲带的地震活动主要为密集的浅源地震,缺失中深源地震.进一步分析揭示:①脱水和榴辉岩的形成在南海洋壳到达软流圈前就基本停止.马尼拉俯冲带南部在较浅的深度就转变为塑性变形,并停...     

Study of the Relation Between the Features of Fault Deformation Tendency Anomaly and Earthquake Activity in the West of China

Using the tendentious accumulation rate of crustal deformation,DC,the spatial distributionfeatures of deformation across fault in the West of China was studied;the regional patterns ofdeformation accumulation induced by fault activity was established and its seismogenicmeaning was discussed.The types of fault deformation evolution in the time domain and thefeatures of change of large extent anomaly in fault deformation which occurred in 1995～1996was analyzed comprehensively.It was indicated definitely that 1995～1996 is the turningpoint of fault network activity in the West of China since the 1990s;it is closely related to thechange of main seismic active regions in the West of China,i.e,the alternation of strong/weak stages and the change of action range of tectonic stress field in the Qinghai-Tibet blockand its environs;and hence it is of medium-and short-term precursor meaning for the changeof the overall pattern of earthquake activity in the West of China in the year 1996.On such abasis,a preliminar     

A potential stratotype for the regional lowermost stage of the continental Paleocene in China

Phanerozoic chronostratigraphic units can only be defined through their lower boundary stratotypes.The lowermost stage of the Paleocene of China,which mainly consists of terrestrial deposits,can only be defined through its lower boundary stratotype,i.e.the continental Cretaceous/Paleogene boundary stratotype.There is no section yet found which contains continuous terrestrial deposits and biostratigraphic records of the Cretaceous-Paleogene transition in Nanxiong,Guangdong and Jiayin,Heilongjiang,there is no evidence for establishing the continental stratotype of the Cretaceous/Paleogene boundary in either area.Therefore,both the"Shanghuan stage"and"Furaoan stage"are not good candidates for the lowermost stage of the Paleocene of China.From the viewpoint of charophytes,the outcrop section of the Dangyang,Hubei Province(Central China)contains the most continuous,abundant and diverse terrestrial biostratigraphic records of the Cretaceous-Paleogene transition,in particular the early Paleocene,known so far in the world.The biostratigraphic records of ostracods in the transition are also continuous,rich,and diverse.The Dangyang outcrop section is the only section known so far in China that is a possible candidate for a continental stratotype of the Cretaceous/Paleogene boundary in China and the section is the only potential section identified to date for establishing the regional lowermost stage of the Paleocene,Paleogene and Cenozoic in China or stratotype section for the stage.     

中国大陆地震趋势分析

在近年全国地震大形势研究的基础上。根据中国大陆地震活动的时空强演化图像及其相关参数的统计结果,并结合大陆周围附近地区强震活动对其内部的影响等客观现象,对大陆地震活动趋势进行了研究预测。结果认为,中国大陆第五地震活跃期到2001年已经结束,2008年3月21日新疆于田7．3级地震可能是中国大陆新的地震活跃期开始。     

近50 a中国东部和西部湖区水量空间变化趋势

基于近代湖泊水量(水位、水深和面积)记录,对近50 a中国东部和西部湖区水量的空间变化趋势进行半定量研究.结果表明:整体上看,20世纪80年代以前,东部湖区水量呈现波动变化而西部湖区水量基本趋于减少;80年代以后东部和西部湖区水量均表现为不同程度的增加.其中,20世纪50年代,东部和西部湖区水量状况基本相似,均保持高湖面特征.20世纪60年代,东部湖区水量有所减少但幅度不明显,而西部湖区以中高水量为主.20世纪70年代,不同区域湖泊基本都保持中湖面特征.20世纪80年代,东部湖区水量呈增加趋势而西部湖区水量相对70年代略有减少.20世纪90年代,东部和西部湖区水量均表现为增加趋势.进一步研究发现,最近50 a来中国不同区域湖泊水量发生变化除了气候因素的驱动外,人类活动的影响也是不可忽视的.     

General characteristics of the recent horizontal crustal movement in Chinese mainland

1 Introduction of GPS observation dataThe Crustal Movement Observation Network of China (CMONOC) is a major scientific project in China organized by China Seismological Bureau and paticipated by the Bureau of Surveying and Mapping of the General Staff, the Chinese Academy of Sciences and the National Bureau of Surveying and Mapping. Based on the observation data of 25 fiducial stations and 56 basic stations in CMONOC (Figure 1 and Table 1), collected from August 26 to September…     

Temporal and spatial features of the soil moisture in boreal spring in eastern China

Soil moisture data of 45 years from European Center for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) and the in situ observational data are used to study the temporal and spatial characteristics of the soil moisture in boreal spring in the area to the east of 100°E in China. Results show that ERA-40 soil moisture well reproduces the temporal and spatial features of observations. ERA-40 data capture the spatial pattern that the soils in Northeast China and Southwest China are wetter than those...     

中国地震学会2000年工作总结暨2001年学术活动计划

总结了中国地震学会2000年的工作，内容包括中国地震学会2000年的学术交流活动、组织工作和科学普及工作；介绍了中国地震学会2001年来的学术活动计划。     

中国大陆大地震危险性判定的经验方法与实例研究

对大陆地震危险性判定的经验指标(地震活动图像异常因子)进行了初步归纳，结合当前震情趋势对未来10a大陆地震的危险性作出了初步判定。