2016 New Zealand Earthquake Surface Displacement Analysis

Below is a project from GEOL-412 (Tectonic Geomorphology). The purpose of this project is to quantify surface displacement in all three principle axis following the 2016 Kaikōura Earthquake.

I started by using Raster Algebra to find the difference in elevation values between two DEM rasters (known as vertical differencing). This allowed me to easily delineate the fault scarps and take a before and after profile (Fig. 1).

I then used pre and post-earthquake DEMs and iterative closest point data to quantify displacement over the fault scarp on the 2016 Papatea earthquake fault scarp (several fault zones ruptured in the 2016 New Zealand earthquake). Iterative closest point is an algorithm that minimizes the differences between two raster layers to make an accurate estimate of a three-dimensional displacement vector at each point. Unlike vertical differencing, it will take into account lateral components of slip (strike slip). This means that ICP yields N-S, E-W, and up/down displacement vectors for the Papatea fault.

A map of Papatea fault and delineated fault scarps can be seen in Figure 2.

Estimates of displacement vectors visible in figures 3, 4, 5.

Fig. 2: Map of Papatea fault scarp following 2016 earthquake.

Fig. 3: Fault displacement with regard to east-west directions. East is positive, west is negative. Black lines represent average values before and after the scarp.

Fig. 4: Fault displacement with regards to north-south directions. North is positive, south is negative. Black lines represent average values before and after the scarp.

Fig. 5: Fault displacement with respect to vertical. Increases in elevation are positive, decreases are negative. Black lines represent average values before and after the scarp.