Optimized volume models of earthquake-triggered landslides

Area of Science:

• Geosciences
• Earthquake Engineering
• Geomorphology

Background:

• The 2008 Wenchuan earthquake triggered a massive number of landslides.
• Accurate estimation of landslide volume is crucial for hazard assessment and mitigation.
• Existing landslide volume-area power-law relationships may not fully capture complex earthquake-induced landslide dynamics.

Purpose of the Study:

• To propose and validate optimized models for calculating total landslide volume.
• To compare the performance of different models and data fitting methods.
• To estimate the total volume of landslides triggered by the 2008 Wenchuan earthquake.

Main Methods:

• Utilized pre- and post-quake Digital Elevation Models (DEMs) for volume calculation of 1,415 individual landslides.
• Fitted data to a conventional landslide volume-area power-law relationship and three proposed optimized models.
• Employed both log-transformed linear and original data-based nonlinear least square fitting methods.

Main Results:

• The optimized model incorporating landslide dimensions (length, width, height), lithology, slope, peak ground acceleration, and slope aspect, combined with nonlinear least square fitting, demonstrated superior performance.
• Application of this best-performing model to 196,007 landslides estimated total deposit volume at 1.2 x 10^10 m^3 and source area volume at 1 x 10^10 m^3.
• The estimated total landslide volume significantly exceeded predictions from conventional earthquake magnitude-landslide volume relationships.

Conclusions:

• The developed optimized model provides a more accurate method for estimating earthquake-induced landslide volumes.
• The total landslide volume from the Wenchuan earthquake is substantial, underscoring the significant geomorphic impact.
• There is a clear need to revise and update existing power-law relationships for earthquake-induced landslide volume estimation.