| Summary: |
Landslides are one of the most widespread natural hazards in the world,
responsible for thousands of deaths and billions of dollars in property damage every year.
However, predicting landslide potential at a global scale using real-time monitoring is very
difficult and expensive in terms of time and money. This is especially true in developing
countries where expensive ground observation networks are prohibitive and in
mountainous areas where access is minimize. This paper studies the relationship
between rainfall and landslides event in Yogyakarta and Central of Java area. Landslides
events and the triggering rainfall are collected from Kalibawang (Yogyakarta), Kebumen,
Karanganyar, Banjarnegara (Central of Java). The landslide type at those locations is
identified as shallow, deep-seated, and debris flow. Loss and damages of settlement and
people was reported during the landslide occurrence. Based on the data collection from
those landslide occurrences, an empirical rainfall threshold was determined based on
intensity-duration (ID) and cumulative-intensity (EI) relationship. The threshold curve was
obtained from the rainfall data using an objective statistical technique. The proposed ID
and EI curves are also compared with the global existing rainfall threshold. The ID curve
for the studied region is higher than the global rainfall threshold that proposed by several
investigators. However, new regional rainfall thresholds for Yogyakarta and Central of
Java can be used in a regional operational landslide warning system based on local or
regional precipitation measurements where local and regional thresholds are not
available.
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