TITLE:
Research on Deformation Mode of the Longmenshan-Longriba Region Using GPS and Leveling Data
AUTHORS:
Xudong Li, Wei Li, Jiangtao Qiu, Bing Feng, Xiang Liu
KEYWORDS:
Longmenshan Fault Zone, Longriba Fault Zone, GPS, Strain, Leveling
JOURNAL NAME:
International Journal of Geosciences,
Vol.14 No.7,
July
26,
2023
ABSTRACT: The Longmenshan-Longriba region is located on the
eastern edge of the Tibetan Plateau, and is an ideal place to study the
eastward extrusion and uplift mechanism of the plateau. Previous studies on
this area mainly focused on tectonic activity and seismic hazard, with few
studies giving its overall deformation characteristics and dynamic mechanism.
This paper uses the latest dense GPS data, combined with precise Leveling data
to analyze the kinematic characteristics
and deformation mode of the Longmenshan fault zone (LMSF) and the Longriba
fault zone (LRBF). The results show that both the Longmenshan fault zone and
the Longriba fault zone have certain right-lateral strike-slip and
thrusting, indicating that they play an important role in adjusting strain
distribution and absorbing tectonic deformation; The strain-rate field on the Longriba
fault zone is broadly distributed, suggesting that the deformation field is at
least partially coupled; while the strain-rate field on the Longmenshan fault
zone presents a non-uniform distribution, indicating different dynamic sources
acting on segments. The high strain rate areas revealed in this study points us
to the high-risk area for future earthquakes. The present-day vertical motion
velocity field in the region obtained from Leveling and GPS data shows a
mismatch between the regional deformation field and active tectonics, which can
be explained by the incomplete coupling of deformation between the lower and
upper crust.