TRANSTEQ - Modeling and Understanding Transient Earthquake Deformation

• Applicant: Professor Marcos Moreno, Ph.D.
• Subject Area: Palaeontology
• Term: from 2015 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 281471150

Despite a wealth of recent geophysical and geodetic data on subduction zones, the physical mechanism and kinematics of strain accumulation and release in the earthquake cycle still await precise characterization. On April 1st 2014 the north-central fraction of the Northern Chile seismic gap was struck by a Mw=8.1 earthquake on the plate interface, which was preceded by foreshock clusters (the largest of which beginning on March 16th 2014) and a transient deformation signal as detected by continuous GPS stations in the vicinity of the ruptured segment. The multiparameter instrumentation of the Integrated Plate Boundary Observatory Chile (IPOC) has successfully captured the deformation evolution since 2007 up to today, providing an unprecedented opportunity to understand and quantify the preparatory kinematic processes leading up to a great earthquake as well as relaxation of stresses both on the plate interface and in the viscoelastic media of the subduction zones. Our main scientific goal is to provide insights into the interaction mode of earthquakes and transient deformation. In doing so, we will analyze and simulate the kinematics of spatial-temporal changes of deformation related to the Iquique earthquake. These will include (1) Processing of GPS and InSAR time series of surface deformation in the pre- and postseismic phases, (2) Detection of low magnitude transient deformation signals, (3) Numerical modeling of subduction zone mechanisms that are responsible for the observed transient deformation field during the interseismic, coseismic and early postseismic periods. In particular it will allow us to investigate competing hypotheses between seismic and aseismic slip processes controlling transient deformation, dominant process in the pre- and post-phases of megathrust earthquakes and test what controls variations in the locking degree and its control on earthquake rupture boundaries. We also envision determining to which extent geodetic and seismic observations are diagnostic of preparatory processes, providing key elements to improve the knowledge of the physical mechanisms that operate within the earthquake system adding to future monitoring strategies and hazard assessment at subduction zones.

• DFG Programme: Research Grants