Earthquake-induced soil landslides: volume estimates and uncertainties with the existing scaling exponents

Abstract

Quantifying landslide volumes in earthquake affected areas is critical to understand the orogenic processes and their surface effects at different spatio-temporal scales. Here, we build an accurate scaling relationship to estimate the volume of soil landslides based on 1 m pre- and post-event LiDAR elevation models. On compiling an inventory of 1719 landslides in Mw 6.6 Hokkaido earthquake epicentral region, we find that the volume of soil landslides can be estimated by γ = 1.15–1.18. The total volume of eroded debris from Hokkaido catchments based on this new scaling relationship is estimated as 64–72 million m3. Uncertainties from the existing scaling relationships are found large except for the one found in recent literature 1. Based on the GNSS data approximation, we noticed that the co-seismic uplift volume is smaller than the eroded volume, suggesting that frequent large earthquakes may be counterbalancing the topographic uplift through erosion by landslides.