从大尺度和小尺度两方面研究郯庐断裂带苏鲁段地壳介质非均匀性.使用地震波数据,研究了郯庐断裂带苏鲁段地壳速度结构的非均匀性,单位虚波Qmps的非均匀性,地壳介质泊松比的非均匀性,反映地壳介质小尺度非均匀性的分层κ值和y值.计算了1668年郯城81/2级地震震源区长度和沿断裂带的震源区边界,根据地震构造和地震活动性确定断裂的闭锁段,地震应力的积累单元和调整单元.对比1668年郯城81/2级地震的地壳介质状况,将各种非均匀性参数综合分析,结果表明,各种参数指向一致,未来大震的可能区域是33°—34.5°N,118°—118.8°E的北北东向区域,震级可达8级.

地壳介质的非均一性对反演上地幔顶部速度和地壳厚度具有重要影响.文中对福建地区地壳上地幔顶部的速度结构进行联合反演,结果显示福建地区地壳浅层主要以高速异常特征为主,与区域内山脉特征相对应,而在中下地壳主要以低速异常为主,区域内速度异常与区域断裂构造密切相关.该结论进一步证实沿政和-大埔断裂带存在低速带,但低速异常主要出现在深20～30km的中下地壳部分,与前人所得的低速异常区相比范围更大,出现深度更深.联合反演结果显示福建陆域地壳厚度为28～35km,地壳在沿海地区偏薄,向内陆逐渐变厚,与接收函数的结果较为一致,且发现沿永安-晋江断裂东侧存在显著的地壳减薄特征.上地幔顶部速度结果显示在政和-大埔断裂带西侧以高速异常为主,在福州盆地及沿海区域表现为低速异常.

郯庐断裂带穿越中国东部鲁、苏、皖等3省,文中称此段为郯庐断裂带鲁苏皖段.通过地震地质、深地震勘探、天然地震层析成像、地震活动、地貌和现今地壳运动速度场等方面资料的分析和对比研究,根据历史地震重演原则和地质构造类比原则,对郯庐断裂带鲁苏皖段未来强震的可能发生地段进行了探讨.泗洪南(王集)—嘉山一带与1668年郯城81/2级地震震中地区对比分析发现,两处在深、浅部地质构造、新构造运动、地震活动性等方面存在较大的相似性.结合郯庐断裂带鲁苏皖段7级及以上强震的分布及其重现周期等方面综合分析,初步认为,郯庐断裂带鲁苏皖段在泗洪南(王集)—嘉山一带存在发生7级或7级以上强地震的可能性.

采用多震相走时反演法获得了郯庐断裂带鲁苏段及附近（30°～37°N，113°～122°E）地壳三维速度结构。对地壳内分层速度结构的分析发现，郯庐断裂带鲁苏段存在速度的分段特征。

（1）研究区三维速度结构的非均匀性。用6268个地震，123022个Sg-Pg,Sm-Pm,Sn-Pn到时差资料，使用多震相地震走时成像法获得了郯庐断裂带鲁苏段及附近地壳（30°～37°N，113°～122° E）三维速度结构，发现在20～25 km层部分地区存在低速异常区,主要是郯庐断裂带临沭到定远及以东的地区，1668年郯城地震区位于其内,1668年郯城地震发生在莫霍面埋深变化的区域，而郯庐带宿迁到泗洪及以东地区是莫霍面变化较大的地方。

郯庐断裂带鲁苏皖段主要是沂沭断裂带,该段自东向西分布着5条断裂.该段及邻区在大地构造位置上跨越中朝断块、扬子断块和秦岭-大别褶皱带3个一级构造单元,是多个构造单元的交汇部位.

Two destructive earthquakes occurred in the southern Liyang region,Jiangsu Province in 1974 and 1979,with magnitude 5.5 and 6,respectively. The 1979 Liyang earthquake with magnitude 6 is the largest earthquake in the land area in the province in modern times. The interval between the two earthquakes is 5 years,and their meizoseismal areas overlap basically,indicating that the seismogenic structures of the two earthquakes belong to a same active fault. Based on field investigations,many scholars believed that the seismogenic structures of these two earthquakes were related to the NNE-trending Maodong Fault. In recent years,more in-depth studies were conducted in this region,e.g.shallow seismic prospecting,high density electric prospecting,drilling exploration and seismic geological investigation. And with the accumulation of data and the precise location of aftershocks in the earthquake region,a clearer understanding has been gained of the seismogenic fault of the Liyang earthquakes. The main shocks and the aftershocks of the two earthquakes are all distributed along the Jintan-Nandu Fault located 2km east of the Maodong Fault. Both main shocks are located at the intersection of the southern segment of Jintan-Nandu Fault and the near-EW-trending Liyang-Nandu Fault. Thus,the authors conclude that the Jintan-Nandu Fault is the major seismogenic fault for both Liyang earthquakes.

Non-isostatic state of the lithosphere causes anomaly in geophysical fields, on the other hand, analysis on geophysical fields in an area may be helpful for identifying whether the lithosphere is isostatic or not. In this paper, geophysical data, such as gravity anomaly, geothermal flow, wave velocity structure in deep crust, and seismic tomographic result, etc., were systematically analyzed. And also investigated the regional seismicity, crustal motion velocity and deformation observations, geo-history development in Cenozoic periods, Quaternary sediments and active faults in Nanjing and its neighbor area. We hold that the geological structure in Nanjing region is relatively stable. Based on the result we think that no large earthquakes would occur in the study region, and the destructive earthquakes possibly occurred in the future in Nanjing region may be moderately strong or weaker ones.

<正>地壳物质组成、特定地壳结构或地震构造是地震孕育的母体,区域动力作用环境(力源)是地震孕育、发生的必要条件。在活动板块边缘(如印度板块与欧亚板块碰撞带、菲律宾海板块和太平洋板块与欧亚板块碰撞带),地震活动较强,地震密集,在板块内部或不活动板块边

Based on data of systematic age sampling,Quaternary sediment lithology and palynomorph assemblage analysis on the standard well(N06S6)for Quaternary research in Qinhuai River valley,a stratigraphic unit,Hanfu Formation since Late Pleistocene,was set up for Quaternary stratigraphy in the Qinhuai River valley.Five palynological assemblages were distinguished through an intensive study on pollens and spores from the well,and five stages in the evolution of vegetation and climate were correspondingly reconstructed for the Late Quaternary in this area.The Quaternary paleoenvironment,paleoclimate and paleo- landform was also recovered in the area,which indicates that the paleo-landform changed little and new tectonic movement during this time was weak in the study area.

On the basis of the textual research on the historical earthquake data and the field investigation of Wudu earthquake occurred in 186 B.C., we suggest that the earthquake parameters drawn from the present earthquake catalogs are not definite and amendments should be made. The heavily-damaged area of this earthquake should be located between Jugan township of Wudu County and Pingding township of Zhouqu County. Its epicenter should be in the vicinity of Lianghekou in Wudu County with a magnitude of about 7∼7¼ and an intensity of about IX∼X. The major axis direction of the heavily-damaged area should be in the WNW direction that is approximately consistent with the strike of the middle-east segment of Diebu-Bailongjiang active fault zone, and the origin time should match up to that of the latest paleoearthquake event [before (83±46) B.C.] obtained by the trench investigation. Certain seismic rupture evidences are still preserved on this fault segment. Therefore, we propose on the basis of comprehensive analysis that the causative structure of the M 7∼7¼ Wudu earthquake in 186 B.C. should be in the middle-east segment of Diebu-Bailongjiang active fault zone.

The Changjiang fault zone,also known as the Mufushan-Jiaoshan fault,is a famous fault located at the southern bank of the Changjiang River,near the Nanjing downtown area.Based on multidisciplinary data from shallow artificial seismic explorations in the target detecting area（Nanjing city and the nearby areas）,trenching and drilling explorations,classification of Quaternary strata and chronology dating data,this paper provides the most up-to-date results regarding activities of the Changjiang fault zone,including the most recent active time,activity nature,related active parameters,and their relation to seismic activity.

The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Xizang(Tibet) Plateau. Maqu fault is the easternmost segment of the East Kunlun active fault. Based on the three trenching, four Holocene palaeo-earthquake events are identified since Holocene along the Maqu Fault. The interval is between (1730±50)a and (1802±52)a from nowadays to the time of the latest palae-earthquake event, and interval of the second palaeo-earthquake events is between (3736±57)ka and (4641±60)ka, and the third palaeo-earthquake events is (8590±70)ka based on nowadays, and the last times is (12.2±1.7)ka to nowadays. Thereinto,time of the first and second palaeo-earthquake events is more credibility than the third and last times. As a result,recurrence intervals of the palaeo-earthquake events about the easternmost segment of the East Kunlun active fault is approximately 2400 ka, and the palaeo-earthquake Elapsed time is between (1730±50)a and (1802±52) form nowadays.

The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Tibet Plateau.Maqu Fault is the easternmost segment of the East Kunlun active fault.Based on the field investigation,the activity along the Maqu fault since Holocene has been characterized by left-lateral(sinistral) strike-slip and normal slide faulting.The characteristics of dislocation geomorphology are obvious.The fault runs through the Maqu County,and then extends to east along the southern side of Heihe River and through the Ruoergai Grassland,and the end of Maqu fault reaches Qiuji on northern sides of the Minshan Mountain.Moreover,based on measurement of geomorphologic offset at the two sites by Total Station Instrument and the sample dating,the authors discussed new activity of Maqu fault and slip rate since Holocene.The average rate of horizontal displacement is calculated as 6.29~5.71 mm/a since early stage of Holocene and 4.19~4.03 mm/a since late stage of Holocene,respectively.

近年来,通过艰苦的野外现场考察和室内相关资料的系统调研,对1879年武都南8级大震的震级、震害、烈度分布、同震破裂及其形成该事件的发震构造、形成机制等方面的问题进行了专题研究.本文对武都南8级大震的宏观震中位置、震级及同震破裂研究结果进行了总结.重点讨论了该历史事件同震破裂的分布范围、破裂类型、规模及其形成机制等方面的问题.研究结果表明:(1)武都南地震的极震区主体位于甘肃东南部的武都与文县之间,且靠近武都南,为一呈北东东向展布的椭圆形,长轴长约70km,短轴长约30km,宏观震中位于极震区东部的堡子坝附近.(2)极震区内分布有3条向北东撒开,向南西收敛的同震破裂带.(3)主破裂带西起哈南白水江,东至固水子、透坊、稻畦子一带的白龙江沿岸.(4)同震破裂主要由地震裂缝、地震陡坎、地震鼓包、地震滑坡、堰塞湖等构造类型组成,其中以滑坡现象最为突出,保存也最为完整.(5)根据同震破裂的产生部位、几何结构和形成机制,可认为武都南地震的同震破裂带是在哈南-稻畦子-毛坡拉断裂带左旋走滑兼倾滑活动作用下形成的.(6)根据同震破裂的规模及发震断裂运动量实测数据,可以确定武都南地震震级已达8级.

抗震设防决策过程中涉及到许多对整个分析过程都具有重要意义的模糊信息,本文提出一种结合模糊信息进行地震危险性概率分析与抗震设防决策的方法,介绍了用模糊集模拟模糊信息的原理,以及进一步处理模糊信息的区间分析顶点法.作为一例,这些方法结合基于泊松分布的地震烈度发生概率模型,应用于南京市区未来50年的地震危险性与抗震设防效益分析,提供模糊的结论供设防决策参考.