The role of geomorphology, rainfall and soil moisture in the occurrence of landslides triggered by 2018 Typhoon Mangkhut in the Philippines

Abanco Martinez De Arenzana, Claudia, Bennett, Georgie, Matthews, Adrian, Matera, Mark and Tan, Fibor (2021) The role of geomorphology, rainfall and soil moisture in the occurrence of landslides triggered by 2018 Typhoon Mangkhut in the Philippines. Natural Hazards and Earth System Science. ISSN 1684-9981 (In Press)

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Abstract

In 2018 Typhoon Mangkhut (locally known as Typhoon Ompong) triggered thousands of landslides in the Itogon region of the Philippines. A landslide inventory of Typhoon Mangkhut is compiled for the first time, comprising 1101 landslides over a 570 km2 area. The inventory is used to study the geomorphological characteristics and land cover more prone to landsliding as well as the hydrometeorological conditions that led to widespread failure. The results showed that landslides mostly occurred in slopes, covered by wooded grassland in clayey materials predominantly facing East-Southeast. Rainfall (GPM IMERG) associated with Typhoon Mangkhut is compared with 33 high intensity rainfall events that did not trigger regional landslide events in 2018. Results show that landslides occurred during high intensity rainfall, coinciding with the highest soil moisture values (clays saturation point), according to SMAP-L4 data. This indicates that, in addition to rainfall from the typhoon, soil moisture plays an important role in the triggering mechanism. Our results suggest that SMAP-L4 and GPM IMERG data show potential for landslide hazard assessment and early warning where ground-based data is scarce. However, other rainfall events in the months leading up to Typhoon Mangkhut that had similar or higher intensities and also occurred when soils were saturated did not trigger widespread landsliding, highlighting the need for further research into the conditions that trigger landslides in typhoons.

Item Type: Article
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: LivePure Connector
Date Deposited: 24 Mar 2021 00:41
Last Modified: 14 May 2021 00:05
URI: https://ueaeprints.uea.ac.uk/id/eprint/79545
DOI: 10.5194/nhess-2020-259

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