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Remote Observations of Surface Rupture and Fault Kinematics in the January 7, 2025, Southern Tibet Plateau Earthquake

Description: 

On January 7, 2025, an Mw 7.1 earthquake occurred in the south-central Tibetan Plateau (USGS event us6000pi9w) as a result of predominately normal faulting in the shallow crust. The earthquake was felt >500 km away and caused violent shaking (MMI IX) near the epicenter causing at least 126 casualties and >$1 billion estimated economic loss. USGS moment-tensors derived from global seismic observations indicate an approximately north-south oriented fault plane (187° or 349°) dipping moderately east (49°) or west (42°). Preliminary observations from Sentinel1 InSAR and visual and sub-pixel correlation analysis of PlanetScope (3 m/pixel) and WorldView (0.5 m/pixel) optical images are consistent with the west-dipping fault plane. However, these observations also indicate a more complex rupture that may include a listric primary fault, an antithetic secondary fault, and possibly a component of lateral tectonic motion not indicated by most focal mechanisms. WorldView images show widespread liquefaction and lateral spreading features in valleys and near lakes, as well as discontinuous dip-slip scarps that extend for at least 30–35 km near the Lhagoi Kangri dome that mostly coincide with pre-existing fault scarps. Sentinel1-derived interferograms reveal a broad zone of decorrelation primarily west of the mapped surface rupture indicative of diffuse deformation and a secondary lobe of deformation ~15–20 km west of the mapped surface rupture, possibly implying a smaller antithetic fault. Preliminary sub-pixel correlation of WorldView and PlanetScope images show localized deformation coincident with the mapped discontinuous rupture overprinting a broader, primarily east-west extensional signal. Initial finite-fault modeling indicates that a single planar fault cannot account for both seismic and satellite observations; instead, the data require that fault dip shallows with depth, consistent with listric faulting. Together, these observations are consistent with the regional pattern and long history of east-west oriented extension in the shallow crust of the Southern Tibet Plateau.

Session: Late-breaking on Recent and Future Large Earthquakes [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Jessica

Student Presenter: No

Invited Presentation: 

Poster Number: 145

Authors