Three-dimensional Crustal Structure of the Namche Barwa Massif on the Basis of Travel-time Imaging of Body Waves
LI Minjuan
SHEN Xuzhang
MA Haiping
LIU Baiyun
SONG Ting
LIU Jinrui
TAN Jiawei
CHEN Xiao
DOU Xiying
Abstract：The Namche Barwa massif is located in the core area of the eastern Himalayan syntaxis.This area is located at the junction of the Eurasian plate,Indian plate and Myanmar block.It is the key part of the southeastward lateral strike-slip extrusion and 90° deflection of the plate boundary on the Tibetan Plateau.It is also the region with the strongest tectonic stress and the fastest uplift rate and denudation.It is of great significance to study the velocity structure of this area to understand the mechanism of earthquake preparation.On the basis of the dense array data of 374 short-period nodal seismometers deployed in the Namche Barwa area between June 14 and July 24,2020,in combination with the data of the regional seismic network from 2009 to 2024,the double-difference tomography method was used in this study to obtain the velocity structure characteristics and precise relocation of earthquake results of Namche Barwa and its vicinity.The results show the north and east sides of the Namche Barwa peak are located in the high-velocity anomaly area,whereas the southwest side is located in the low-velocity anomaly area.At a depth of 10km with high resolution,the P-wave velocity structure in the middle section of the Jiali fault changed from high-velocity anomaly to low-velocity anomaly.The trend of P-wave and S-wave high-velocity and low-velocity anomaly areas is consistent with the trend of the main active fault zones.From a depth of 5km,the wave velocity ratio of the Namche Barwa massif and its vicinity is low,and the phenomenon is more significant with the increase in depth.
Keywords：The Namche Barwa massifdouble-difference tomographythree-dimensional velocity structuremilin earthquake
Publication Date：2025-09-30
Online Publishing Date：2025-10-28(First online date of this platform, not the publication date of the document)
Pages：13( 790-802 )