Insights on the influence of fault maturity on earthquake behavior in the Qinghai-Tibetan Plateau from coseismic deformation fields and tectonic geomorphology

Fault structural complexity is one of the main characteristics associated with immature faults and the delocalization of coseismic deformation over hundreds of meters. However, many complex parameters and processes control fault zone evolution and deformation localization. Thus, their primary controls vary, and establishing the dominant controls for a particular fault is challenging. We combine coseismic and longer-term geomorphic data from faults in the Qinghai-Tibetan Plateau, where many complex fault systems interact to accommodate the convergence of the Indian and Eurasian plates. This region is ideal for furthering the understanding of fault zone evolution and its consequences for earthquake behavior, since these fault systems comprise immature to very mature segments and have hosted numerous earthquakes in recent years. Multiple imaging geodesy platforms have captured the tectonic geomorphology and coseismic surface deformation fields of these faults, shedding light on past and current fault interactions. Furthermore, detailed field surveys, slip rate and maximum cumulative slip estimates are available for many of these faults. We explore the relationships between fault maturity, fault interaction and coseismic deformation on multiple faults in the Qinghai-Tibetan Plateau using coseismic surface offsets measured in the field and from optical image correlation and SAR offset deformation fields, off-fault deformation estimates, the spatial variation in geologic slip rates and fault roughness. Our observations highlight variations in maturity within a fault system and the complexity of assessing the controls on deformation localization.