| Popis: |
In February 25, 2018 an earthquake of magnitude Mw 7.5 occurred in Papua New Guinea leading to approximately 10,000 landslides. The event was followed by a series of aftershocks and rainfall events that also triggered more than a thousand of landsides. Our analyses show that large landslides are abundant throughout the study area. We show that landslides concentrate, in particular, across the boundaries of specific rock units e.g., Sisa volcanics and Wongop sandstone or at highly stress zones related to the subducted tectonic activities in the region. The complex setup of the rough topography, the different geologic structural features, and the different properties of the lithological units make it interesting to understand the contribution of each parameter individually to the concentration of the landslides at specific unit boundaries or at specific structural features.In this research, we run a serious of full waveform spectral element simulations using point sources of the earthquake and the aftershocks. We use 3D Earth models which mimic the lithological and structural settings as well as the steep topography of the study area of the Papua New Guinea. As a result, we aim at better understanding possible cause of seismic amplification that could occur along weakness surfaces. Specifically, we test if vertical variation of the geological units with different strength (and/or permeability) over steep hillslopes could lead to amplification of seismic waves. The results can shed the light on the complex nature of the landslides distribution associated with large earthquakes that leads to catastrophic societal and economical losses. |
