Interseismic fault slip deficit and coupling distributions on the Anninghe-Zemuhe-Daliangshan-Xiaojiang fault zone, southeastern Tibetan Plateau, based on GPS measurements

Abstract

The Anninghe-Zemuhe-Daliangshan-Xiaojiang (AZDX) fault zone is an important boundary between the South China block and southeastern (SE) Tibetan Plateau. Its strong earthquake potential has been highly concerned, because remarkable left lateral strike-slip motion has been observed in this fault zone. Using the linear spherical block model constrained by a refined GPS horizontal velocity field, we have derived the detailed partial slip deficits and the coupling fraction distributions along the AZDX fault zone, as well as self-consistent long-term slip rates on major active faults in SE Tibetan Plateau. Our results identified three remarkable slip deficit regions with high fault coupling fractions (0.6–1.0), including the southern segment of the Anninghe Fault (north of Xichang), the southern segment of the Daliangshan Fault (Butuo-Qiaojia), and southern terminus of the Xiaojiang Fault. These regions spatially coincide with the seismic gaps inferred from the spatiotemporal distributions of historical earthquake ruptures and paleoearthquake surveys, jointly implying their higher strong earthquake potential. Furthermore, combining with analyses of GPS data, previous geological and numerical simulation studies, we tentatively discussed the possible effect range of the Burma arc tectonic domain.