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| Titel |
Generalised form of a power law threshold function for rainfall-induced landslides |
| VerfasserIn |
Jose Cepeda, Manuel Roberto Díaz, Farrokh Nadim, Kaare Høeg, Anders Elverhøi |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038853
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| Zusammenfassung |
| The following new function is proposed for estimating thresholds for rainfall-triggered
landslides: I = α1Anα2Dβ, where I is rainfall intensity in mm/h, D is rainfall duration in h,
An is the n-hours or n-days antecedent precipitation, and α1, α2, β and n are threshold
parameters. A threshold model that combines two functions with different durations of
antecedent precipitation is also introduced. A storm observation exceeds the threshold when
the storm parameters are located at or above the two functions simultaneously. A novel
optimisation procedure for estimating the threshold parameters is proposed using Receiver
Operating Characteristics (ROC) analysis. The new threshold function and optimisation
procedure are applied for estimating thresholds for triggering of debris flows in the
Western Metropolitan Area of San Salvador (AMSS), El Salvador, where up to
500 casualties were produced by a single event. The resulting thresholds are I =
2322 A7d-1D-0.43 and I = 28534 A150d-1D-0.43 for debris flows having volumes
greater than 3000 m3. Thresholds are also derived for debris flows greater than
200Â 000 m3 and for hyperconcentrated flows initiating in burned areas caused by
forest fires. The new thresholds show an improved performance compared to the
traditional formulations, indicated by a reduction in false alarms from 51 to 5 for the
3000 m3 thresholds and from 6 to 0 false alarms for the 200Â 000 m3 thresholds. |
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