Coseismic displacements of 2016 <i>M</i>_W7.8 Kaikoura, New Zealand earthquake, using Sentinel-2 optical images

Optical imagery has been widely applied to monitor the earth surface changes. Sentinel-2 satellite constellation launched lately, provides optical images with short revisit cycle, high spatial resolution, large coverage and free accessibility. Thus it has great potential in surface deformation mornitoring. Based on the coregistration of optically sensed images and correlation (COSI-Corr) software package, we obtained the ground deformation field of the 2016 MW7.8 Kaikoura, New Zealand Earthquake from the multi-temporal Sentinel-2 data, using the sub-pixel cross-correlation technique. We systematically analyzed the system error sources of Sentinel-2 image pairs and proposed a modified subtraction method to mitigate the satellite attitude jitter distortions in the deformation field. Then, we compared the results of four bands(Band 2/3/4/8)with the spatial resolution of 10-meter and the statistic results show that Band8 is the optimum band for ground deformation monitoring. Moreover, we mapped the coseismic displacement field of the earthquake from Sentinel-2 optical images, and analyzed the slip distribution along the major faults. The results indicate that the maximum horizontal slip is up to 10 meters. For accuracy evaluation, we also calculated the coseismic displacement field of this event using the Landsat8 panchromatic images. The results indicate that Sentinel-2 has higher precision for the ground deformations monitoring. This research provides a good reference for the application of the Sentinel-2 optical images in future