大兴安岭造山带及两侧邻区莫霍面深度与泊松比分布特征  

Distribution of the Moho Depth and Poisson’s Ratio Beneath Greater Khingan Range Orogenic Belt and Its Surrounding Regions

作　　者：杨彦明[1] 张建中[1] 黄瑞滨 Yang Yanming;Zhang Jianzhong;Huang Ruibin(Earthquake Agency of Inner Mongolia Autonomous Region,Hohhot 010010,China;Chifeng Seismic Station,Chifeng 024000,Inner Mongolia,China)

机构地区：[1]内蒙古自治区地震局,呼和浩特010010 [2]赤峰地震台,内蒙古赤峰024000

出　　处：《中国地震》2019年第2期211-225,共15页Earthquake Research in China

基　　金：中国地震局监测、预测、科研三结合课题(3JH-201902002);内蒙古自治区地震局局长基金重点课题(2018ZD05)共同资助

摘　　要：利用2009~2016年内蒙古自治区数字地震台网宽频带固定地震台站的远震波形数据,采用接收函数 H-k 算法获得23个基岩台站下方的莫霍面深度和泊松比,同时,收集并筛选出277个已有探测台阵和流动台站的接收函数研究结果,综合分析给出大兴安岭造山带及两侧邻区莫霍面深度、泊松比的分布特征。研究表明,研究区域的莫霍面在整体上呈现自东向西逐渐加深的特征,莫霍面深度为25 . 0~42 . 3km,平均约为33 . 5km。莫霍面最浅的区域为松辽盆地(深度为27 . 0~35 . 0km),最深的区域为大兴安岭重力梯级带以西地区(深度为41 . 0~42 . 3km)。研究区域泊松比为0 . 19~0 . 33,平均值为0 . 26,大于全球大陆地壳的平均值。泊松比高值异常区集中在火山岩区及具有较厚沉积层的盆地。台站所处位置的海拔与莫霍面深度之间具有较强的正相关性,艾里补偿模式在研究区成立,莫霍面起伏与区域地形地貌特征间具有显著的镜像关系。大兴安岭地区的莫霍面深度与泊松比间存在显著的反相关关系,而在松辽盆地及周缘地区未发现明显的规律性,这也意味着松辽盆地在构造演化过程中经历了更为复杂的地壳改造过程。We collect waveforms of worldwide teleseismic events by 23 broadband seismic stations from the Inner Mongolia Autonomous Region Digital Seismic Network during period of 2009-2016. Using the receiver functions of the H-k method,we calculated the Moho depth and Poisson s ratio beneath those stations constructed on bedrocks. We present the Moho depth and Poisson s ratio distribution characteristic of Greater Khingan Range orogenic belt and surrounding regions based on a compilation of 277 seismic observation array and mobile seismic array for receiver functions H-k analysis published in the literature and our results. Comprehensively analyzing the fine crustal constrains distribution information in this study leads to the following conclusions. The Moho depth of the study area gradually increases from east to west overall,varies from 25 . 0km to 42 . 3km and the mean of 33 . 5km,with the shallowest and deepest Moho being located in the Songliao Basin (27 . 0-35.0km) and the western of the Greater Khingan Range gravity anomaly gradient belt (41 . 0-42 . 3km), respectively. The average Poisson s ratio is about 0 . 27 and varies from 0 . 19 to 0 . 33 for the study area. It is higher than the average Poisson s ratio of global continental crust. The highest Poisson s ratio is found in the volcanic region and basin with the thick sediment layer. The Moho depth correlate well with the surface topography and the Airy s isostasy model is suitable for this area. The existence of significant anticorrelation between Moho depth and Poisson s ratio in the Greater Khingan Range area. However,no clear correlation is observed in the Songliao Basin and its adjacent area. It may reflect that the area experienced quite complex processes of crustal modification in the tectonic evolution process of the Songliao Basin.

关 键 词：莫霍面深度 泊松比 接收函数 大兴安岭 造山带 

分 类 号：P315[天文地球—地震学]