New threshold for landslide warning in the southern part of Thailand integrates cumulative rainfall with event rainfall depth-duration
A landslide-triggering rainfall threshold for the southern part of Thailand was introduced. The new threshold explicitly integrates the variables of event rainfall and cumulative rainfall from precipitation data corresponding to 92 landslide events in the study area. To determine event rainfall, a s...
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Published in | Natural hazards (Dordrecht) Vol. 113; no. 1; pp. 125 - 141 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Dordrecht
Springer Netherlands
01.08.2022
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | A landslide-triggering rainfall threshold for the southern part of Thailand was introduced. The new threshold explicitly integrates the variables of event rainfall and cumulative rainfall from precipitation data corresponding to 92 landslide events in the study area. To determine event rainfall, a suitable inter-event criterion (
IEC
) had to be defined that separated two consecutive rainfalls. A rainfall intensity no greater than 2 mm/day lasting at least 1 day (
IEC
2,1
) was the criterion established to separate two consecutive rainfalls in the study area. Using quantile regression, an event rainfall depth-duration (
ED
) threshold was drawn at a probability level of 5%. A 20-day cumulative event rainfall depth (
CR
20
) was the most suitable duration of cumulative rainfall depth. A
CR
20
of 100 mm was the third rainfall variable to give a threshold that integrated cumulative rainfall with event rainfall depth-duration (
CED
). This threshold is proposed for the study area depicted in three-dimensional space. The
CED
threshold is implemented by an assessment of
CR
20
followed by an assessment of
ED
. The hit rate (
HR
) of the
CED
threshold is a little lower than the
HR
of the
ED
threshold, but the
CED
threshold is far better than the
ED
threshold in terms of false alarm rate (
FAR
) since the
CR
20
of 100 mm filters out many non-triggering rainfalls prior to the assessment of the event rainfall. |
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ISSN: | 0921-030X 1573-0840 |
DOI: | 10.1007/s11069-022-05292-0 |