Two multi-temporal datasets to track the enhanced landsliding after the 2008 Wenchuan earthquake

Abstract

Abstract. We release two datasets that track the enhanced landsliding induced by the Mw 7.9 2008 Wenchuan earthquake over a portion of the Longmen mountains, at the eastern margin of the Tibetan plateau (Sichuan, China). The first dataset is a geo-referenced multi-temporal polygon-based inventory of pre- and coseismic landslides, post-seismic remobilisations of coseismic landslide debris, and post-seismic landslides (new failures). The inventory covers 462.5 km2 in the earthquake's epicentral area, from 2005 to 2015. The second dataset records the debris flows that occurred from 2008 to 2017 in a larger area (~ 17,000 km2), together with information on their triggering rainfalls recorded by a network of rain gauges. For some well-monitored event, we provide detailed information on rainfall, discharge, flow depth and density. The datasets can be used to analyse, at various scales, the patterns of enhanced landsliding caused by the earthquake. They can be compared to inventories relative to past or new earthquakes or other triggers to reveal common or distinctive controlling factors. To our knowledge, no other inventories that track the temporal evolution of earthquake-induced mass wasting have been made freely available thus far. Our datasets are available at https://doi.org/10.5281/zenodo.1405490. We also encourage other researchers to share their datasets to facilitate research on post-seismic geological hazards.

Earthquake‐Induced Chains of Geologic Hazards: Patterns, Mechanisms, and Impacts

“…Enhanced rates of landsliding are common in earthquake‐hit regions. Rainfall can either trigger new landslides (Marc et al, ) from rock material that is weakened and damaged by shaking or remobilize EQTL material (Domènech et al, ; Fan et al, ; Fan, Domènech, et al, ) that can feed debris flows for many years after the earthquake (Figure ; Lin et al, ; Tang et al, ). Still, our knowledge of the timing and extent of post‐seismic landslides, debris flows, and sediment transport hinges on observations rather than predictions.…”

“…Estimates of post‐seismic landsliding rates come from detailed compilations of inventories collected from satellite imagery (e.g., Fan et al, ; Marc et al, ), and these studies show that pulses of enhanced landslide frequency and sediment flushing occurred within 1–10 years after the earthquake. Many studies have reported that both rates of landsliding and sediment transport decay toward background rates within a decade (Dadson et al, ; Hovius et al, ; Khattak et al, ; C. ‐W.…”

“…Exhaustion of the total volume of available sediment (Cruden & Hu, ) is unlikely because most of the EQTL sediment (as much as 80–90%) can remain on the hillslope for many years after the initial event. Landslides that remain active after the earthquake tend to occur closer to channels and in parts of the landscape with higher contributing drainage areas (Fan et al, ) than dormant landslide deposits, although remobilization might not depend solely on fluvial undercutting (e.g., Croissant, Lague, Davy, et al, ; Croissant, Lague, Steer, & Davy, ) where stream power is low and coarse sediment protects the base of landslide deposits.…”

“…Despite a growing number of inventories of coseismic landslides (see section ), detailed data and time series of the geomorphic reworking of thus produced material are few (X. Fan et al, ). Future research might wish to consider the following: The causes for the spiked landslide rates after earthquakes remain insufficiently understood.…”

“…Predicting the dynamics of coseismic landslide scars and deposits yields insight on how quickly effects of widespread mass wasting attenuate. In the area affected by the Wenchuan earthquake, Fan et al () created a multitemporal post‐seismic debris‐flow database that includes 527 debris flows in 244 watersheds. They also collected rainfall data from 91 rain gages, which they correlated to analyze the relation between rainfall and debris‐flow characteristics (data set release: Domènech et al, ).…”