【作者】 唐方头；

【导师】 张培震； 邓志辉；

【作者基本信息】 中国地震局地质研究所 ， 构造地质学， 2003， 博士

【摘要】 中国大陆现代以块体构造变形为主要特征。随着研究工作的深入，块体活动的普遍性被越来越多的科学工作者所认同，导致了活动地块理论的诞生。活动地块是被形成于晚新生代、晚第四纪(100～120kaB.P.)至现今强烈活动的构造带所分割和围限、具有相对统一运动方式的地质单元。活动地块边界构造活动强烈，绝大多数强震都发生在地块边界的活动构造带上。活动地块具有新生性、层次性、整体性和立体性四个基本特征。中国大陆及邻区可以划分出6个一级活动地块，它们是：青藏、西域、华南、中缅、华北和东北活动地块。华北地块位于中国大陆的东部，与青藏、西域、华南和东北4个一级活动地块相邻，其地震活动强度和构造变形在东部地区最强，也是中国大陆强震活动最强烈的地区之一。华北地区人口稠密、经济发达，也是祖国的首都所在地。加强华北地块构造变形和地震活动规律的研究，对于防震减灾，为国民经济建设服务，具有重要意义。本文以华北地块为研究对象，对华北地块近期构造变形和强震活动进行了较为详细的研究，初步认识了华北地块内部与边界带的构造变形、强震活动的关系，并对其成因机制进行了初步探讨。 一、中国大陆的活动地块与强震活动 在前人对中国大陆活动地块划分的基础上，研究了中国大陆活动地块与强震活动的关系。进一步证实了中国大陆的强震活动明显受活动地块的控制，其中52％以上的6级地震、73％以上的7级地震和100％的8级地震发生在一、二级活动地块的边界带内；多个活动地块边界带相互交汇、相互作用的地带往往是强震高发区；特别是几个一级活动地块的交汇部位，更是强震集中发生的地区；而且不同构造部位地块的活动性也有差异，以南北地震带为界，西部地块的活动性等明显高于东部地块，在西部地区，青藏地块活动性最高，而对于东部地区，华北地块活动最强烈。 二、华北地块与强震活动 利用华北地块已有研究成果，对华北地块的构造演化特征进行了研究，认识到华北地块内的主要构造单元都表现出新生与继承的辩证发展。根据地块内地质、地球物理与强震活动等资料，将华北地块进一步划分成3个二级地块(鄂尔多斯、华北平原和鲁东—黄海)，并对其中的一些二级地块进一步细分为三级和四级地块。 通过对华北地块内强震活动的研究，进一步证实了活动地块对地震活动的控制作用。华北地区二级活动地块边界带和活动地块内部5级以上地震的密度相差2.5倍以上，每平方千米地震释放能量是地块内部的30倍以上；7次8级特大地震都发生在一级、二级活动地块的边界带上；7级大震除一级、二级活动地块的边界带外，在三级活动地块的边界带上也有分布，而4级活动地块的边界带上只有6级强震发生。研究结果表明，华北地块不同构造部位的构造单元内的活动强度存在差异，对于二级地块：华北平原块体活动最强、鄂尔多斯块体活动最弱；对于三级地块：东南鄂尔多斯亚块体活动性大于西北鄂尔多斯亚块体，豫皖亚块体活动性明显大于太行亚块体和冀鲁亚块体；对于边界带：鄂尔多斯西南弧活动性最强烈，而华北平原块体和鲁东—黄海块体的南部边界带则活动较弱；大致以NE向大同—环县基底隐伏断裂、豫皖亚块体西边界和鲁西微块西边界的连线之间是华北地区活动最强的区域。 华北地块地震活动在时间上具有明显的活跃期与平静期交替出现的特征，在空间上不同活跃期有不同主体活动区域。第一跃期7级以上大震主要发生在鄂尔多斯块体的边界带；第二活跃期7级以上大震主要分布在鄂尔多斯和华北平原块体的边界带上;而第三活跃期7级以上大震除在二级活动地块的边界带发生外，在华北平原和鲁东一黄海块体的内部也有分布。研究还发现华北地块不同震级地震在活动地块内部和边界带的分布差异很大，震级越大两者的差异越大;地块级别降低，各震级地震的频度和能量释放在块内与边界带的比值都减，J\。三、华北地块近期构造应力场和断裂活动研究 利用近期震源机制解资料研究华北地块构造应力场，证实了区内主压应力方向为NE一NEE，强震发生主要受区域应力场控制。同时发现，在强震活跃期间，在与强震发生有关的边界带内震源机制解主压应力P轴的方向与区域应力场基本一致，而在地块内和其它边界带上则存在一定的差异;平静期间，则总体与区域应力场基本一致。 利用GIS对华北地块活动断裂与地震活动进行统计研究后现，华北地块内地震活动在不同时期受不同构造控制。具体表现为，在1474一1804地震活动活跃期内，强震主要受NE断裂组控制;1805年以来强震主要受NW断裂组控制。1970年以来，5级以下地震活动主要受NE断裂组控制;6级以上强震主要发生在NE和NW断裂组交汇区内。 跨断层测量资料表明，邦庐断裂带和太行亚块体内断裂的近期构造变形强度明显小于张家口一渤海断裂带和山西断陷带;山西断陷带东缘断裂的近期构造变形强度明显弱于西缘;华北地块对于NE走向断裂作用为主的构造单元(包括地块和边界带)，强震活动时段的断层运动速率明显小于强震活动较弱的时段;对于NW走向断裂作用为主的构造单元，强震活动时段的断层运动速率明显大于强震活动较弱的时段;对于NE、NW走向断裂?更多还原

【Abstract】 Block motion is one of the most remarkable features of present tectonic deformation in the Chinese mainland. The active block theory has been formed as the more and more scientists are convinced of universality of block activities by studies. The active blocks are geological elements with similar motion modes, which were formed in Late Cenozoic and cut and enclosed by strong active tectonic belts from Late Quaternary to present-day. Deformation and major earthquakes usually occur along their boundaries. The active blocks have four basic characteristics: newly generating, layering and ordering, entirety and solid. The Chinese mainland and its adjacent regions could be divided into six active tectonic block regions(the first order): Tibet, West Region, North China, South China, Northeast China and China-Burma region. The North China active tectonic block region is located at East Chinese mainland and borders to Tibet, West region, South China and Northeast China active tectonic block regions. Its earthquake activity and tectonic deformation are the strongest in eastern China, and it is one of regions in the Chinese mainland with high seismicity. There are dense population and highly developed economy in North China. The capital of China is also located, in the North China. It is important for earthquake prevention and disaster reduction to study tectonic deformation and seismicity regularity of this region. This thesis is focused on detailed studying recent tectonic deformation and earthquake activity of North China. The purpose is to reveal the relationship of tectonic deformation and earthquake activity between active tectonic block and their boundaries. The author has also studied the mechanism of tectonic deformation and strong earthquake activity in North China.1 The active tectonic blocks and strong earthquake activity in the Chinese mainlandBy studying the relationship between active blocks and strong earthquake activity in the Chinese mainland, the author further confirms that strong earthquakes are obviously controlled by active blocks. More than 52% earthquakes(M>6.0), more than 73% earthquakes(M>7.0) and 100% earthquakes(M>8.0) occur along boundaries belonging to the first and second order blocks. Major earthquakes often occur in the belts where several active blocks interact. Especially there are more and denser strong earthquakes in the belts where several active tectonic block regions interact. The activity of active blocks is different at varied tectonic positions. The activity of western active blocks is obvious stronger than that of the eastern active blocks with the South-North Earthquake Belt as a boundary. The activity of Tibetan active tectonic block region is strongest in the west part of the Chinese mainland, and the activity of North China active tectonic block region is strongest among eastern active tectonic block regions2 The North China active tectonic block region and its strong earthquake activityAfter studying tectonic evolution characteristics of the North China active tectonic block region based on previous research, author has postulated that the main tectonic elements have rejuvenilezed. Some boundaries followed the old tectonic belts, and some boundaries were newly formed during geological evolution history. By geology, geophysics, strong earthquake activity data and so on, the North China active tectonic block region could be divided into three active tectonic blocks(Ordos, North China Plain and East Shandong-Yellow Sea active tectonic blocks)as second order active tectonic block. Some active tectonic blocks could be divided into lower order active tectonic blocks further(sub-block, min-block).By studying strong earthquake activity within the North China active tectonic block region, it is confirmed that active tectonic blocks control strong earthquake distribution. Between boundaries andblock interiors, the differences of the density of earthquakes(M>5.0) are more than 2.5 times, and that of the energy released in per square kilometers exceed 30 times. The 7 great ear更多还原