[J02-3] Recent large earthquakes III

[J02-3-02] Surface Ruptures that could have been caused by aftershocks of the 2016 Kaikoura earthquake

^○Sidao Ni (Instite of Geodesy and Geophysics, Chinese Academy of Sciences)

Surface ruptures provide essential information for identification of causative faults, inferring earthquake source parameter scaling laws and estimation of recurrence and magnitude of future earthquakes. However, some surface ruptures are not necessarily generated coseismically by the mainshock, and instead could be caused by aftershocks. Surface ruptures on more than 10 faults have been observed after the 2016 M7.8 Kaikoura earthquake, making it one of the most complex events involving of multiple faults. In order to investigate whether some of the surface breaks are caused by aftershocks, we relocated the two M6.5 aftershocks and a few ~M6 aftershocks and determine their centroid depth as well as moment tensors. Rupture directivity of some of the aftershocks are also studied with a recently developed method of measuring the difference between centroid and hypocenter location. Preliminary results suggest that some surface ruptures could be caused by aftershocks. Accordingly, the surface breaks and ground deformation caused by the aftershocks should be taken into account when modeling rupture processes of the mainshock with geodetic or geological observations.