摘要
基于腾冲火山区31个地震台站记录到的远震和面波频散数据,采用多频接收函数H_(-κ)叠加方法,与多频接收函数和面波联合反演方法,本文获得了研究区的地壳厚度、平均V_(P)/V_(S)以及S波速度.结果表明,腾冲火山区地壳厚度与V_(P)/V_(S)分别在32.4~39 km和1.73~2.01范围内变化,平均值分别为35.86 km和1.86.薄地壳和高V_(P)/V_(S)主要分布在腾冲断裂东边缘两个局部区域.S波速度在~10 km,~20 km,~30 km和~50 km深度附近存在大尺度的低速异常区,部分不同深度的低速体相互联通.我们推测,幔源岩浆首先聚集在上地幔顶部,随后沿腾冲断裂带东缘的局部地区上涌至下地壳富集,再由不同通道依次向中地壳、上地壳迁移并持续富集,部分岩浆沿着多个通道在早晚更新世和全新世喷出地表,形成了腾冲火山区至今广泛分布的火山口.
Based on the teleseismic and surface wave dispersion data recorded by 31 seismic stations in the Tengchong volcanic area,and using the multi-frequency H_(-κ)stacking of receiver function and the joint inversion of multi-frequency receiver function and surface wave data,we obtained crustal thicknesses,average V_(P)/V_(S)and S-wave velocities in the Tengchong volcanic area.The results show that the crustal thickness and V_(P)/V_(S)of the study region vary in the ranges of 32.4~39 km and 1.73~2.01,with the mean values of 35.86 km and 1.86,respectively.Thin crust and high V_(P)/V_(S)are mainly distributed in two localized areas along the eastern margin of the Tengchong Fault.Large-scale low-velocity anomalies are observed around the depths of~10 km,~20 km,~30 km and~50 km,with interconnected low-velocity bodies across these depth levels.We hypothesize that mantle-derived magma was initially enriched at the top of the upper mantle,subsequently upwelled to the lower crust through localized zones along the eastern margin of the Tengchong Fault with further enrichment,then migrated upward via distinct channels sequentially through the mid-to upper crust while undergoing continuous enrichment.Portions of the magma ultimately erupted to the surface through multiple conduits during the Early to Late Pleistocene and Holocene,forming the widely distributed craters still visible today in the Tengchong volcanic area.
作者
范心甜
危自根
储日升
谢军
李雪垒
FAN XinTian;WEI ZiGen;CHU RiSheng;XIE Jun;LI XueLei(State Key Laboratory of Precision Geodesy,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430077,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;School of Microelectronics and Physics,Hunan University of Technology and Business,Changsha 410205,China)
出处
《地球物理学报》
北大核心
2025年第3期845-856,共12页
Chinese Journal of Geophysics
基金
国家自然科学基金(42325401,42474094)
湖北省自然科学基金(2023AFB1076)
湖北省科技创新人才专项(2022EJD015)资助。
关键词
腾冲火山区
地壳厚度与V_(P)/V_(S)
低S波速度区域
岩浆上涌和运移
多频接收函数和面波联合反演
Tengchong volcanic area
Crustal thickness and V_(P)/V_(S)
Low S-wave velocity zone
Magma upwelling and transport
Joint inversion of the multi-frequency receiver function and surface wave data
作者简介
第一作者:范心甜,女,2000年生,硕士研究生,主要从事地震学壳幔结构研究.E-mail:Fanxintian23@mails.ucas.ac.cn;通讯作者:危自根,男,1984年生,副研究员,主要从事地震学壳幔结构研究.E-mail:weizigen@apm.ac.cn。
