地球与行星物理论评（中英文）2026，Vol.57Issue(5)：543-552,10.DOI:10.19975/j.dqyxx.2025-055
龙日坝断裂带深部结构及动力学研究进展
A review of the deep structure of the Longriba fault zone and its geodynamic processes
摘要
Abstract
The Longriba fault zone represents a major active structure within the Songpan-Ganzi block,de-marcating pronounced contrasts in surface topography,crustal deformation,and deep crustal properties between the eastern and western parts of the block.Controversy persists regarding its deep geometry:magnetotelluric profiles typically image the fault terminating at the top of a mid-lower crustal conductive layer,whereas active-source seis-mic reflection profiles reveal it as a crustal-penetrating structure extending to the Moho.Teleseismic P-wave travel-time tomography suggests a southeast-dipping fault that extends at least into the mid-lower crust.Low-temperature thermochronology indicates that fault activity likely initiated around 38 Ma,driven by far-field stress propagation following the India-Eurasia collision.Tectonic analyzes further link the fault to regional evolution,noting that the eastern margin of Qinghai-Xizang Plateau experienced significant denudation during the Late Cretaceous and Late Cenozoic,with the latter accounting for～80%of total erosion,focused predominantly between the Longriba and Longmenshan fault zones.This spatial pattern suggests that the Longriba fault zone plausibly acts as a back-thrust to the Longmenshan fault zone,with both structures jointly accommodating crustal uplift and growth deformation in this region.Although current seismicity along the Longriba fault zone is low,its long evolutionary history,sub-stantial surface trace,deep penetration,Late Pleistocene slip higher,and evidence of paleoseismic events from trench studies collectively imply its considerable seismic potential risk.Given the ongoing India-Eurasia conver-gence,this fault zone warrants careful attention in regional seismic hazard assessment.关键词
龙日坝断裂带/演化历史/地震活动性/深部结构/构造意义Key words
Longriba fault zone/evolutionary history/seismicity/deep structure/tectonic implications分类
天文与地球科学引用本文复制引用
李泉美,武振波,周卿..龙日坝断裂带深部结构及动力学研究进展[J].地球与行星物理论评（中英文）,2026,57(5):543-552,10.基金项目
国家自然科学基金资助项目(42174077,42574121) Supported by the National Natural Science Foundation of China(Grant Nos.42174077,42574121) （42174077,42574121）
