地质力学学报2026，Vol.32Issue(4)：919-932,14.DOI:10.12090/j.issn.1006-6616.2025187
阿尔金断裂中段南侧白干湖断裂遥感影像特征及地震危险性
Remote sensing image characteristics and seismic hazard of the Baiganhu Fault on the south side of the central Altyn Tagh Fault
摘要
Abstract
[Objective]Accurately delineating the spatial distribution and geometric scale of active faults is essential for understanding crustal deformation and assessing regional seismic hazards.While the Altyn Tagh Fault(ATF)has been extensively studied,its adjacent secondary structures—such as the Baiganhu Fault—remain poorly constrained regarding their geometry,slip history,and seismic potential.This study aims to systematically characterize the offset geomorphology of the Baiganhu Fault,establish its segmentation,and evaluate its potential for generating large earthquakes,including multi-fault cascading ruptures with the ATF.[Methods]Using multi-source high-resolution satellite imagery and digital topographic data,we conducted detailed geomorphic mapping of the Baiganhu Fault.Displaced landforms(e.g.,offset gullies,alluvial fans,pressure ridges,and sag ponds)were measured.We constrained displacement variations at individual measurement points using Gaussian cumulative probability density(COPD)distributions to interpret the displacement accumulation pattern and evaluate coseismic slip.[Results]The Baiganhu Fault extends for approximately 247 km along a general northeast-east(NEE)strike,displaying prominent left-lateral strike-slip geomorphic features.Based on fault geometry and deformation patterns,it is divided into western,central,and eastern segments.The central segment hosts a well-preserved～50-km-long surface rupture zone with an average coseismic displacement of 4.8 m.Statistical analysis of 99 offset gullies yields an average horizontal offset of 4.3-4.8 m for the most recent event,corresponding to a moment magnitude of MW 7.4±0.3.A full-segment rupture could generate an earthquake of MW 7.8±0.3.Furthermore,the～5-km-wide stepover separating the Baiganhu Fault from the main strand of the ATF is unlikely to act as a permanent barrier,making a cascading rupture mechanically plausible.[Conclusions]The Baiganhu Fault is a highly active left-lateral structure capable of generating MW 7.4 events.Regional seismic hazard models must incorporate the scenario of cascading ruptures between the Baiganhu Fault and the Altyn Tagh Fault to avoid underestimating seismic risk to surrounding infrastructure.[Significance]This study provides critical quantitative constraints on the geometry,slip behavior,and seismic potential of a previously under-studied secondary structure within the ATF system.By highlighting the potential for multi-fault cascading ruptures,our findings underscore the need to update regional seismic hazard models,which is vital for risk mitigation and infrastructure safety in the region.关键词
活动地块/走滑断裂/阿尔金断裂/白干湖断裂/地震地表破裂Key words
active tectonic block/strike-slip fault/Altyn Tagh Fault/Baiganhu Fault/seismic surface rupture分类
天文与地球科学引用本文复制引用
刘汉琳,陈涛,袁兆德..阿尔金断裂中段南侧白干湖断裂遥感影像特征及地震危险性[J].地质力学学报,2026,32(4):919-932,14.基金项目
国家自然科学基金项目(41902216) This research was financially supported by the National Natural Science Foundation of China(Grant No.41902216). （41902216）
