Control of style-of-faulting on spatial pattern of earthquaketriggered landslides|
Gorum, T. & Carranza, E. J. M.
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 Yingxiu–
Beichuan 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.
Distance distribution analysis; Fry analysis; Evidential belief functions; Geographic information system; Yingxiu–Beichuan fault; 2008 Wenchuan earthquake