Geological risk assessment of traffic engineering construction among 7.0–8.5 magnitude earthquake areas: Practice from the Sichuan-Tibet transport corridor in the eastern Tibetan Plateau

Abstract

At least 13 active fault zones have developed in the Ya’an-Linzhi section of the Sichuan-Tibet transport corridor, and there have been undergone 17 M_S ≥ 7.0 earthquakes, the largest earthquake is 1950 Chayu M_S 8.5 earthquake, which has very strong seismic activity. Therefore, carrying out engineering construction in the Sichuan-Tibet transport corridor is a huge challenge for geological technological personnel. To determining the spatial geometric distribution, activity of active faults and geological safety risk in the Sichuan-Tibet transport corridor. Based on remote sensing images, ground surveys, and chronological tests, as well as the deep geophysical and current GPS data, we investigated the geometry, segmentation, and paleoearthquake history of five major active fault zones in the Ya’an-Linzhi section of the Sichuan-Tibet transport corridor, namely the Xianshuihe, Litang, Batang, Jiali-Chayu and Lulang-Yigong. The five major fault zones are all Holocene active faults, which contain strike-slip components as well as thrust or normal fault components, and contain multiple branch faults. The Selaha-Kangding segment of the Xianshuihe fault zone, the Maoyaba and Litang segment of the Litang fault zone, the middle segment (Yigong-Tongmai-Bomi) of Jiali-Chayu fault zone and Lulang-Yigong fault zone have the risk of experiencing strong earthquakes in the future, with a high possibility of the occurrence of M_S ≥ 7.0 earthquakes. The Jinsha River and the Palong-Zangbu River, which is a high-risk area for geological hazard chain risk in the Ya’an-Linzhi section of the Sichuan-Tibet transport corridor. Construction and safe operation Ya’an-Linzhi section of the Sichuan-Tibet transport corridor, need strengthen analysis the current crustal deformation, stress distribution and fault activity patterns, clarify active faults relationship with large earthquakes, and determine the potential maximum magnitude, epicenters, and risk range. This study provides basic data for understanding the activity, seismicity, and tectonic deformation patterns of the regional faults in the Sichuan-Tibet transport corridor.