SONNE SO324

Using a dense onshore-offshore array of seismometers, we will explore how subduction zones terminate and transfer motion into continental transform plate boundaries.

Our science objectives are to test three hypotheses (H1-H3) that address outstanding science questions surrounding subduction to strike-skip transition:
H1: Spatial variability in upper-plate structure, elastic-properties and degree of deformation, control the frictional properties and slip behavior along the subduction megathrust.
H2: Structural inheritance relating to plate boundary evolution strongly influences the kinematics of current deformation and how strain is distributed. In central New Zealand, this may manifest as active deformation along ancestral faults through Cook Strait and reactivation of structures at the margin of the impinging Chatham Rise.
H3: Pronounced changes in upper plate fault connectivity and strike direction limit the dimensions of upper-plate fault ruptures. In the case of central New Zealand, we will test whether such fault segmentation was the reason for the NE termination of the Kaikōura earthquake rupture in Cook Strait.