Optimized volume models of earthquake-triggered landslides

Abstract

In this study, we proposed three optimized models for calculating the total volume of landslides triggered by the 2008 Wenchuan, China Mw 7.9 earthquake. First, we calculated the volume of each deposit of 1,415 landslides triggered by the quake based on pre- and post-quake DEMs in 20 m resolution. The samples were used to fit the conventional landslide “volume-area” power law relationship and the 3 optimized models we proposed, respectively. Two data fitting methods, i.e. log-transformed-based linear and original data-based nonlinear least square, were employed to the 4 models. Results show that original data-based nonlinear least square combining with an optimized model considering length, width, height, lithology, slope, peak ground acceleration, and slope aspect shows the best performance. This model was subsequently applied to the database of landslides triggered by the quake except for two largest ones with known volumes. It indicates that the total volume of the 196,007 landslides is about 1.2 × 1010 m3 in deposit materials and 1 × 1010 m3 in source areas, respectively. The result from the relationship of quake magnitude and entire landslide volume related to individual earthquake is much less than that from this study, which reminds us the necessity to update the power-law relationship.

Two comparable earthquakes produced greatly different coseismic landslides: The 2015 Gorkha, Nepal and 2008 Wenchuan, China events

“…However, neither of these two volumes appears to depart greatly from the trend derived from Keefer's function (Fig. 4) (Xu et al, 2016), but its actual volume is only about 1.5×10 6 m 3 , given that its average depth is 2 to 3 m (Kargel et al, 2016;Collins and Jibson, 2015). Another useful comparison can be made with the Tangjiashan Landslide (31.843°N, 104.432°E) triggered by the Wenchuan Earthquake, which covers an area 0.719×10 6 m 2 that is comparable to the Langtang slide.…”

“…1.208 5 of Xu et al (2016). Unfortunately, currently no inventory is available that spans all scales of coseismic landslides triggered by the Gorkha Earthquake.…”

“…6 (average 15.7×10 6 ) m 3 estimated using the power law (Xu et al, 2016 than the Wangjiayan and Xinzhong landslides, so several hundred Wenchuan-event landslides must be larger than the Langtang landslide. Therefore, the total volume ratio between landslides triggered by the two earthquakes should be greater than the aforementioned value by about 13.05/1.13=11.55 times, normalized by earthquake magnitude.…”

“…These landslides cover a total area of 44.78×10 6 m 2 . We selected the formula V=1.314 7×A 1.208 5 (±0.013 1) of Xu et al (2016) to estimate the total volume from a selection of "volume-area" power law relationships for landslides, (e.g., Xu et al, 2016;Parker et al, 2011;Larsen et al, 2010) because this scaling relation was derived from an original data-based nonlinear least square analysis and sampled 1 415 landslides triggered by the Wenchuan Earthquake and is probably the most suitable for landslides triggered by the two earthquakes. The relationship was applied to each slide mass, yielding a total estimated volume of (444-584)×10…”

Erosion Associated with Seismically-Induced Landslides in the Middle Longmen Shan Region, Eastern Tibetan Plateau, China

“…The 2008 Mw 7.9 Wenchuan earthquake triggered numerous landslides, and provided a rare opportunity to study the geomorphic response to a strong earthquake ( Figure 1). Due to the limitation of available data in previous studies, landslide volumes have typically been derived from landslide areas using statistical equations [4,[10][11][12][13]. Researchers also tried using the spaceborne interferometric synthetic aperture radar (InSAR) [14] and remote sensing and digital terrain model (DTM) data [15] to evaluate mass wasting volume, but only concentrated on the giant Daguangbao [16][17][18].…”