Characteristics and influencing factors of rainfall-induced landslide and debris flow hazards in Shaanxi Province, China

In: Natural hazards and earth system sciences: NHESS, Band 19, Heft 1, S. 93-105

Open Access

Abstract

Abstract. Shaanxi Province, located in northwest China and spanning multiple
hydroclimatic and geological zones, has many areas largely suffering from
rainfall-induced landslide and debris flow. The objectives of this study are
to reveal the spatiotemporal characteristics of the two hazards and identify
their major controlling factors in this region based on a region-wide,
comprehensive ground-survey-based hazard inventory dataset from 2009 to 2012.
We investigated the spatiotemporal characteristics of the two hazards and
quantified the relationships between the occurrence rates of the two hazards
and their influencing factors, including antecedent rainfall amount, rainfall
duration, rainfall intensity, terrain slope, land cover type and soil type.
The results show that landslide has a higher occurrence rate and more
extensive distribution than debris flow in this region, while the two hazards
are both concentrated in the south with ample rainfall and steep terrains.
Both of the hazards show clear seasonalities: July–September for landslide
and July for debris flow. Rainfall characteristics (amount, duration and
intensity) and slope are the dominant factors controlling slope stability
across this region. Debris flow is more sensitive to these rainfall metrics
on the high-value ranges than landslide in this region. Land cover is another
influencing factor but soil type does not appear to impose consistent impacts
on the occurrence of the two hazards. This study not only provides
important inventory data for studying the landslide and debris flow hazards
but also adds valuable information for modeling and predicting the two
hazards to enhance resilience to these hazards in this region.