CAJ | 학술논문

青藏高原东缘岩石圈及软流圈结构的研究是认识该区域地壳上地幔的构造形变及高原内部物质向东运移的重要手段。通过搜集四川区域数字地震台站和野外临时地震台站记录的观测资料，采用接收函数共转换点（CCP）偏移叠加成像方法对青藏高原东缘深部结构研究。研究结果揭示：青藏高原东缘的地壳厚度比四川盆地的地壳厚度大10～20 km；在青藏高原东缘与四川盆地的过渡地带，莫霍面处存在大幅度的垂向错断和变形。从青藏高原东缘到四川盆地，岩石圈与软流圈分界面（LAB）显示出深度逐步增加、410 km 间断面深度则有变浅的趋势。在地壳的下界面和 LAB 界面间以及 LAB 界面与410 km 间断面间也存在多条不连续的分层。青藏高原东缘和四川盆地的 LAB 界面的下方都有明显的低速层分布，但它们之间存在差别，四川盆地的 LAB 界面的下方低速层分布较为完整，而青藏高原东缘 LAB 界面下方的低速层分布中可见离散的高速块体分布。青藏高原东缘与四川盆地深部结构的明显差异，体现了该地区的深部地球动力学背景的复杂性。
청장고원동연암석권급연류권결구적연구시인식해구역지각상지만적구조형변급고원내부물질향동운이적중요수단。통과수집사천구역수자지진태참화야외림시지진태참기록적관측자료，채용접수함수공전환점（CCP）편이첩가성상방법대청장고원동연심부결구연구。연구결과게시：청장고원동연적지각후도비사천분지적지각후도대10～20 km；재청장고원동연여사천분지적과도지대，막곽면처존재대폭도적수향착단화변형。종청장고원동연도사천분지，암석권여연류권분계면（LAB）현시출심도축보증가、410 km 간단면심도칙유변천적추세。재지각적하계면화 LAB 계면간이급 LAB 계면여410 km 간단면간야존재다조불련속적분층。청장고원동연화사천분지적 LAB 계면적하방도유명현적저속층분포，단타문지간존재차별，사천분지적 LAB 계면적하방저속층분포교위완정，이청장고원동연 LAB 계면하방적저속층분포중가견리산적고속괴체분포。청장고원동연여사천분지심부결구적명현차이，체현료해지구적심부지구동역학배경적복잡성。
Study the structure of the lithosphere and the asthenosphere on the eastern margin of Qinghai-Tibet Plateau is the basis to recognize the tectonic deformation and the movement form of the internal materials in the crust and the upper mantle.Using the earthquake observation data of the Sichuan Digital Seismic Network and the mobile broadband seismic stations,and the receiver function common conversion point (CCP )migration stack imaging method,this paper studies the deep structure on the east margin of Qinghai-Tibet Plateau.The results show that the thickness of the crust on the eastern margin of Qinghai-Tibet Plateau is deeper than that of Sichuan Basin,about 10~20 km.In the transition zone on the eastern margin of Qinghai-Tibet Plateau and Sichuan Basin,at the Moho interface there exists large vertical offsets and deformation. The lithosphere and asthenosphere boundary (LAB)discontinuity presents the deepening of the depth gradually,and 410 km discontinuity depth also has the trend of decreasing the depth from Sichuan Basin to Qinghai-Tibet Plateau.There are multiple discrete layers tilt to the west between the lower crust discontinuity and LAB discontinuity.And there are also multiple discrete layers between LAB discontinuity and 410 km <br> discontinuity,but the extent of tilt to the west is less.Sichuan Basin and the east margin of Qinghai-Tibet Plateau beneath LAB discontinuity present the low-velocity layer distribution obviously,but there is a difference between them.The low-velocity layer distribution in Sichuan Basin is relatively complete,but on the east margin of Qinghai-Tibet Plateau,there is the discrete high-velocity block distribution in the low-velocity layer.The distinct difference in the deep structure of the eastern margin of Qinghai-Tibet Plateau and Sichuan Basin reflects the complexity of the deep geodynamic background in this region.