Prediction of the area affected by earthquake-induced landsliding
based on seismological parameters
Odin Marc1, Patrick Meunier2, and Niels Hovius1,31Helmholtz Centre Potsdam, German Research Center for Geosciences (GFZ), Telegrafenberg, 14473 Potsdam, Germany 2Ecole Normale Superieure de Paris, Laboratoire de Geologie, 75231 Paris CEDEX 5, France 3Institute of Earth and Environmental Science, University of Potsdam, Potsdam, Germany
Received: 11 Feb 2017 – Accepted for review: 14 Feb 2017 – Discussion started: 15 Feb 2017
Abstract. We present an analytical, seismologically consistent expression for the surface area of the region within which landslides induced by a given earthquake are distributed. The expression is based on scaling laws relating seismic moment, source depth and focal mechanism with ground shaking and fault rupture length and assumes a globally constant critical acceleration for onset of systematic mass wasting. The seismological assumptions are identical to those recently used to propose a seismologically consistent expression for total landslide volume and area. To test the accuracy of the model we gathered geophysical information and estimates of the landslide distribution area for 83 earthquakes. To reduce uncertainties and inconsistencies in the estimation of the landslide distribution area, we propose an objective definition based on the shortest distance from the seimsic wave emission line containing 95 % of the total landslide area. Without any empirical calibration the model explains 56 % of the variance in our dataset, and predicts 35 to 49 out of 83 cases within a factor two, depending on how we account for uncertainties on the seismic source depth. For most cases with comprehensive landslide inventories we show that our prediction compares well with the smallest region around the fault containing 95 % of the total landslide area. Aspects ignored by the model that could explain the residuals include, local variations of the critical acceleration and processes modulating the surface ground shaking, such as the distribution of seismic energy release on the fault plane, the dynamic stress drop or the rupture directivity. Nevertheless, its simplicity and first order accuracy suggest that the model can yield plausible and useful estimates of the landslide distribution area in near-real time, with earthquake parameters issued by standard detection routines.
Marc, O., Meunier, P., and Hovius, N.: Prediction of the area affected by earthquake-induced landsliding
based on seismological parameters, Nat. Hazards Earth Syst. Sci. Discuss., doi:10.5194/nhess-2017-71, in review, 2017.