Control of style-of-faulting on spatial pattern of earthquake-triggered landslides

Abstract

Predictive mapping of susceptibility to earthquake-triggered landslides (ETLs) commonly uses distance to fault as spatial predictor, regardless of style-of-faulting. Here, we examined the hypothesis that the spatial pattern of ETLs is influenced by style-of-faulting based on distance distribution analysis and Fry analysis. The YingxiuBeichuan fault (YBF) in China and a huge number of landslides that ruptured and occurred, respectively, during the 2008 Wenchuan earthquake permitted this study because the style-of-faulting along the YBF varied from its southern to northern parts (i.e. mainly thrust-slip in the southern part, oblique-slip in the central part and mainly strike-slip in the northern part). On the YBF hanging-wall, ETLs at 4.4-4.7 and 10.3-11.5 km from the YBF are likely associated with strike-and thrust-slips, respectively. On the southern and central parts of the hanging-wall, ETLs at 7.5-8 km from the YBF are likely associated with obliqueslips. These findings indicate that the spatial pattern of ETLs is influenced by style-of-faulting. Based on knowledge about the style-of-faulting and by using evidential belief functions to create a predictor map based on proximity to faults, we obtained higher landslide prediction accuracy than by using unclassified faults. When distance from unclassified parts of the YBF is used as predictor, the prediction accuracy is 80 %; when distance from parts of the YBF, classified according to style-of-faulting, is used as predictor, the prediction accuracy is 93 %. Therefore, mapping and classification of faults and proper spatial representation of fault control on occurrence of ETLs are important in predictive mapping of susceptibility to ETLs.

Wildfire Probability Mapping: Bivariate vs. Multivariate Statistics

“…While Bel and Pls indicate the lower and upper probability of the generalized Bayesian theory, their difference (Unc) represents the doubt that the evidence supports a proposition [32]. Disfunction refers to a degree of disbelief in evidence with respect to the proposition [33] and is equal to 1 − Pls (or 1 − Unc − Bel). Therefore, Bel + Unc + Dis for evidence regarding any proposition is always equal to 1 (i.e., the maximum probability) [31,33].…”

Connectivity of earthquake‐triggered landslides with the fluvial network: Implications for landslide sediment transport after the 2008 Wenchuan earthquake

“…Spatial patterns of earthquake-triggered landslides are also sensitive to the sense of motion on the fault [Meunier et al, 2008;Barlow et al, 2015;Gorum and Carranza, 2015]. The Wenchuan landslides occurred in areas of complex faulting, varying along strike from dextral thrust to nearly pure strike-slip motion [Xu et al, 2009;Liu-Zeng et al, 2011;Gorum and Carranza, 2015].…”

“…Spatial patterns of earthquake-triggered landslides are also sensitive to the sense of motion on the fault [Meunier et al, 2008;Barlow et al, 2015;Gorum and Carranza, 2015]. The Wenchuan landslides occurred in areas of complex faulting, varying along strike from dextral thrust to nearly pure strike-slip motion [Xu et al, 2009;Liu-Zeng et al, 2011;Gorum and Carranza, 2015]. We classified the Wenchuan landslides following the approach of Gorum and Carranza [2015], projecting landslides to the nearest segment of the fault rupture that was categorized based on the predominant type of motion (thrust, oblique slip, and strike slip) [Liu-Zeng et al, 2009].…”

“…The Wenchuan landslides occurred in areas of complex faulting, varying along strike from dextral thrust to nearly pure strike-slip motion [Xu et al, 2009;Liu-Zeng et al, 2011;Gorum and Carranza, 2015]. We classified the Wenchuan landslides following the approach of Gorum and Carranza [2015], projecting landslides to the nearest segment of the fault rupture that was categorized based on the predominant type of motion (thrust, oblique slip, and strike slip) [Liu-Zeng et al, 2009]. We calculated the corresponding landslide-channel connectivity for the different types of faulting along each segment (Figure 9g).…”

Rapid assessment of earthquake-induced landslides

“…MMI is a scale classifying the shaking strength observed at a site while PGV and PGA refer to the highest speed of shaking and the largest increase in velocity respectively, experienced by a particle on the ground during an earthquake (Bormann et al, 2013). In order to explain the distribution of EQIL, the role of some earthquake-related factors such as fault-rupture mechanism and fault geometry (e.g., Gorum and Carranza, 2015;Gorum et al, 2013;Tatard and Grasso, 2013) are also introduced in the literature. If these variables are known, they are taken into account, and a ShakeMap is created accordingly (e.g., Wald, 2013).…”