Applying the Newmark Model in the Assessment of Earthquake Triggered Landslides During the 2017 Ms 7.0 Jiuzhaigou Earthquake, China

The 8 August 2017 Jiuzhaigou, China, earthquake (Ms 7.0) occurred within Jiuzhaigou County, northern Aba Prefecture, Sichuan province, China. The earthquake generated 4834 coseismic landslides with individual areas >7.8 m2 over a 600 km2 region. Both the quantity of landslides and the areas that were affected by landslides are similar to those typical for earthquakes of similar magnitude in the eastern Tibetan Plateau, suggesting that the regional geologic structure significantly effects seismic attenuation. Instead of correlating geological and topographic factors with the co-seismic landslide distribution pattern, this study focuses on analyzing the seismic landslide susceptibility, which comes from a calculation of critical acceleration values using a simplified Newmark block model analysis. Results show that seismic landslide susceptibility plays an important role in the co-seismic landslide pattern. Based on the seismic landslide susceptibility, it becomes feasible to provide a quick evaluation of earthquake-triggered landslides when combined with a peak ground acceleration map for an event. Moreover, the correlation between the characteristics of seismic landslide susceptibility and previously observed landslides suggest that an unmapped extension of the Huya fault was the source fault of the Jiuzhaigou earthquake.