华北文安-蔚县-察哈尔右翼中旗剖面S波资料的地质解释

通过对文安—蔚县—察哈尔右翼中旗深地震测深剖面S波资料的处理解释 ,获得本区二维壳幔速度结构和波速比结构。该区的上、中地壳主要由花岗岩组成 ,整体呈脆性 ,其速度比γ值为 1 72左右 ;下地壳的γ值一般为 1 78;上地幔顶部的γ值在 1 82左右 ,表明下地壳与上地幔顶部整体呈塑性的特征。根据波组及γ值横向变化特征 ,推断了该区的几条深大断裂 ,结合本地区的地震活动 ,推测地震的孕育发生不仅与构造相关 ,而且与该区的岩石性质有关     

西吉—中卫地震测深剖面及其解释

通过对南北向的西吉－中卫宽角反射／折射剖面测探资料的二维处理、计算和解释，研究了中宁、中卫和同心一带弧形构造及两侧的壳幔速度结构和深部构造的基本特征。结果表明，3个区域的壳幔速度结构在纵向和横向上均具有明显的非均匀性，标志壳幔深部构造存在着差异，地壳厚度变化大，弧形构造带中部为一莫霍面隆起（深45．0km)，弧形构造带南北两侧上地壳中存在不同的低速块体。     

Tomographic determination of 3－D crustal structure──Joint inversion of explosion and earthquake data

Ｔｏｍｏｇｒａｐｈｉｃｄｅｔｅｒｍｉｎａｔｉｏｎｏｆ３－Ｄｃｒｕｓｔａｌｓｔｒｕｃｔｕｒｅ──Ｊｏｉｎｔｉｎｖｅｒｓｉｏｎｏｆｅｘｐｌｏｓｉｏｎａｎｄｅａｒｔｈｑｕａｋｅ　ｄａｔａＸｉａｎ－ＫａｎｇＺＨＡＮＧ（张先康）；Ｚｈｕｏ－ＸｉｎＹＡＮＧ（杨卓...     

海原断裂带断层通道波观测与破碎带宽度

断层通道波是低速断层破碎带与高速围岩之间的边界相干多重反射形成的,其振幅和频率强烈依赖于断层的几何形态和物理性质,故能用于探测断裂带的内部结构.在宁夏海原西安州附近海原断裂带上,横跨1920年海原8.6级地震地表破裂带布设2条测线,接收测线之间人工爆破激发的断层通道波.每条测线由1台3分量数字地震仪组成,靠近破裂带台间距30～40 m,远离破裂带台间距增大至230～250 m.对测线1的台站接收到的一炮垂直道地震波数据进行了0.1～4.0 Hz频段的滤波,结果表明在S波到时之后存在多组强振幅、低频率、长波链的断层通道波.由断层通道波揭示的海原断裂带在西安州附近的断裂破碎带宽度约为250 m.     

Geometric form of Haiyuan fault zone in the crustal interior and dynamics implications

Introduction The deep faults in the crust have direct relation to the occurrence of earthquakes and the dis-tribution of active seismic zones, so the researches on the geometric form and physical parametersof deep crustal faults are always an important problem in seismology. The researches are not onlysignificant to knowledge the deep tectonic background of strong earthquake and seismogenicmechanism, but also play a very important role in earthquake hazard estimation and earthquakeprevent…     

Study on relationship between deep and shallow structures along north boundary fault of Yanqing-Fanshan basin

IntroductionTheYanqing-Huailaibasin,whichconsistsoftheYanqing-FanshanandHuailai-Zhuolusub-basins,ismainlycontrolledbythenorthboundaryfaultsofthesub-basins.AsabasictectonicunitattheintersectionofthenortheasternendoftheNNE-trendingShanxigrabensystemandtheNW-trendingZhangjiakou-Penglaifaultzone,ithaskepttheintensivetectonicactivityintheQuaternary(YANG,1982;XU,DENG,1988;XU,MA,1992;FANG,etal,1993;Pavlides,etal,1999).Overthepastdecade,manyresearchershaveconductedstudiesonthedetailedstr…     

2-D P-wave velocity structure in the mideast segment of Zhangjiakou-Bohai tectonic zone: Anxin-Xianghe-Kuancheng DSS profile

Introduction The Capital-circle area is the center of politics, economy and culture of China, and manystrong earthquakes occurred here in history. The Zhangjiakou-Bohai tectonic zone located in thearea is an important active zone. In the period of 500 years between AD 1481~1981, 18 earth-quakes with magnitude more than 6 occurred in the area and 11 of them lay in this active tectoniczone. During 1992~2001, continuous GPS observation found sinistral relative movement betweenYanshan Mo…     

The complexity feature of crust-mantle boundary in Zhangbei seismic region and its tectonic implication

The ProP waveform data obtained from a deep seismic sounding profile, which ran through Zhangbei seismic region, were processed by means of both seismic wave complexity coefficient and frequency spectrum analysis methods, and the complexity characteristics of crest-mantle boundary beneath the studied area and its adjacent region were determined. The results show that the place below epicenter can be taken as boundary, the northern side of which is Inner Mongolia axis with small complexity coefficient and the southern side of which is Huai＇an basin with large complexity coefficient. The different spectrum patterns at the two sides of the epicenter were inferred from spectrum analysis. In the epicentral area, there have been multi-period magmatic eruptions since Meso-Cenozoic and craters exist at the surface. From the velocity imaging of middle and upper crust in Zhangbei seismic region it can be found that there are crustal low velocity bodies around the craters and also there are low velocity zones, which went into deep crust. It is suggested that the distinct zones of crust-mantle boundary complexity may be the margin, where the magma had intruded due to magma activity in Meso-Cenozoic. The southern side with large complexity coefficient is deep magmatic activity area and the northern side with small complexity coefficient is stable crust-mantle tectonics. The difference of crust-mantle complexity provides deep background for the development of strong earthquake.     

华北地区上部地壳结构的三维有限差分层析成像

采用正方形网格对华北地区速度模型进行参数化、网格维数为649×90×16,网格间距为1km. 通过对华北地区30条深地震测深剖面的Pg波三维有限差分速度层析成像反演,获得了该地区上部地壳的三维速度结构. 反演结果显示,低速的"棱形"华北盆地被高速的隆起所包围;而华北盆地又由两个大的断陷带中间夹一个隆起所组成.两个大的断陷带又被分割为多个小的断陷盆地.研究区内的断层多为铲式正断层,结晶基底深度变化较大. 所有这些表明华北地区具有复杂的地质构造和发生强震的深部背景.     

北京一丰镇DSS剖面S波资料的解释和推断

利用北京—丰镇及其邻区三分向宽角反射／折射ＤＳＳ剖面（总长３４０．０ｋｍ）所获信息和利用数字处理技术,充分识别、提取了地壳和上地幔顶部的多种Ｓ波折射、反射震相（波组）．结合Ｐ波解释结果,计算了包括Ｓ波速度ｖＳ和泊松比μ在内的二维物性结构,并综合近垂直反射、地质及其它地球物理等资料,给出了该区内深部构造轮廊和相应的解释推断：该剖面的地壳厚度由东边顺义的３５．０ｋｍ左右向西呈增加之势,至丰镇以东为４２．０ｋｍ左右,壳内于延庆以东的下地壳和延庆至涿鹿间的中地壳以及天镇以西的上地壳内各存在一低速体;地壳中由东向西有一厚约５．０～９．０ｋｍ的壳幔过渡带;大部分地区上、中地壳的μ值为０．２５,下地壳的μ值一般为０．２７,上地幔顶部的μ值为０．２８．表明了该区上、中地壳整体呈脆性,下地壳和上地幔顶部整体呈塑性的特征;延庆至涿鹿间,上地壳的低μ值,可能反映该处岩体裂隙（孔隙）发育且呈干燥充气状态,而中地壳的高μ值,则可能反映该处岩体充液（或呈部分熔融状）;根据震相特点、μ值的横向变化特征,确定了该区数条深部断裂．地震大多发生在断裂附近,即μ值显著变化处,并集中于μ值较低一侧的脆性岩体中．