Quantifying rainfall controls on catchment‐scale landslide erosion in Taiwan

Abstract

Landslide erosion is a dominant hillslope process and the main source of stream sediment in tropical, tectonically active mountain belts. In this study, we quantified landslide erosion triggered by 24 rainfall events from 2001 to 2009 in three mountainous watersheds in Taiwan and investigated relationships between landslide erosion and rainfall variables. The results show positive power‐law relations between landslide erosion and rainfall intensity and cumulative rainfall, with scaling exponents ranging from 2·94 to 5·03. Additionally, landslide erosion caused by Typhoon Morakot is of comparable magnitude to landslide erosion caused by the Chi‐Chi Earthquake (MW = 7·6) or 22–24 years of basin‐averaged erosion. Comparison of the three watersheds indicates that deeper landslides that mobilize soil and bedrock are triggered by long‐duration rainfall, whereas shallow landslides are triggered by short‐duration rainfall. These results suggest that rainfall intensity and watershed characteristics are important controls on rainfall‐triggered landslide erosion and that severe typhoons, like high‐magnitude earthquakes, can generate high rates of landslide erosion in Taiwan. Copyright © 2012 John Wiley & Sons, Ltd.

Estimating the Contribution of Loose Deposits to Potential Landslides Over Wenchuan Earthquake Zone, China

“…The volume of the loose deposits corresponding to landslides varied from 966.43 m 3 to 25.1841 × 10 6 m 3 . The standard error of estimate (SEE) of loose deposits volume S v is then (adapted from [29])…”

“…An empirical relationship between the volume of individual landslides and the landslide area is often used to estimate the volume of coseismic loose deposits [29]- [31]. We adopted the power-law relationship between the volume of loose deposits and the area of the landslide as defined by [29] …”

“…We adopted the power-law relationship between the volume of loose deposits and the area of the landslide as defined by [29] …”

“…The uncertainty of total volume S T (in m 3 ) was estimated using the propagation of errors formula [29] …”

Understanding terrestrial organic carbon export : a time-series approach

“…the average time between landslides at a given location). We compile measured rates of landsliding in Taiwan (RL, in % of catchment area per year) for four catchments where data are available (Table 6.S8; Chang and Slaymaker, 2002;Chang et al, 2007;Lin et al, 2008;Chen et al, 2013Chen et al, , 2015. There can be considerable variability at the annual-timescale in landslide rates (Lin et al, 2008) due to extreme landslide triggers, such as the 1999 Chi-Chi Earthquake and the 2009 Typhoon Morakot (West et al, 2010).…”