Deriving the rainfall threshold for shallow landslide early warning during tropical cyclones: a case study in northern Philippines

Title
Deriving the rainfall threshold for shallow landslide early warning during tropical cyclones: a case study in northern Philippines
Publication Date
2018
Author(s)
Javier, Dymphna
Kumar, Lalit
( author )
OrcID: https://orcid.org/0000-0002-9205-756X
Email: lkumar@une.edu.au
UNE Id une-id:lkumar
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Springer Netherlands
Place of publication
Netherlands
DOI
10.1007/s11069-017-3081-2
UNE publication id
une:22542
Abstract
Rainfall-induced landslides (RILs) have been a source of social and economic disruption in the mountainous Baguio area in northern Philippines. Prolonged heavy rainfall usually happens during tropical cyclone and southwest monsoon activity. A pragmatic approach to RIL mitigation is to develop rainfall-based early warning. We implemented a modified regression method to derive the empirical minimum intensity (I)– duration (D) threshold I = 6.46 D-0.28 and a normalized ID threshold NI = 0.002 D-0.28 for rainfall duration ranging between 24 and 264 h. Using a separate data set to evaluate the applicability of the threshold, 93% of the landslide-triggering rainfall events fell above the derived threshold. RILs also occurred when 24-h rainfall was 0.02–28% of the mean annual precipitation or after accumulating at least 500 mm of rainfall from the onset of the rainy season. The thresholds may be further refined as more landslide data become available in the future.
Link
Citation
Natural Hazards, 90(2), p. 921-941
ISSN
1573-0840
0921-030X
Start page
921
End page
941

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