Improving Our Understanding of Liquefaction-Induced Displacements: Integration of Remote Sensing Data and Field Data from the 2010/2011 New Zealand Earthquakes

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Liquefaction is a significant seismic hazard in which the induced ground movements cause severe damage to the built environment. Our understanding of the consequences of liquefaction is hampered by the limited field data that exist regarding liquefaction-induced movements (e.g., lateral spreading) during previous earthquakes. This project will investigate liquefaction-induced lateral spreading during the 2010 Darfield and 2011 Christchurch earthquakes in New Zealand using displacements derived from satellite imagery and LIDAR. These displacements will be integrated with subsurface, topographic, and geologic data to improve our understanding of the factors that influence liquefaction-induced lateral spreading displacements. The results of this work potentially will have far-reaching impact on geotechnical engineering because of new insights into the phenomenon of lateral spreading provided by the dense spatial resolution of the deformations measured by the remote sensing techniques. This work will substantiate a new displacement monitoring technique for the geotechnical community such that future earthquake studies and hazard mapping can take advantage of these techniques. With a combination of improved sensors (e.g., 50-cm resolution optical satellite imagery, 1-m resolution LIDAR) and advanced processing algorithms (e.g., precise georeferencing between images and datasets), it is now possible to monitor sub-meter displacements via remote sensing and at fine spatial resolution on the ground. The unprecedented spatial resolution of the deformations produced by remote sensing combined with the availability of an enormous amount of subsurface data in Christchurch provide a unique opportunity to improve our understanding of the characteristics that influence liquefaction-induced lateral deformations. The project also will involve detailed geologic mapping and interpretation by engineering geologists, and this information will be used to gain further insights into the geologic constraints that influence the observed displacement patterns and lateral spread kinematics. These data will allow us to investigate the influence and interconnections of the subsurface characteristics, spatial variability, geologic conditions, topography, ground motions, etc. on the observed movements; this understanding will improve both empirical and numerical models for predicting lateral spread displacements.