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| Titel |
The disastrous 17 February 2006 rockslide-debris avalanche on Leyte Island, Philippines: a catastrophic landslide in tropical mountain terrain |
| VerfasserIn |
S. G. Evans, R. H. Guthrie, N. J. Roberts, N. F. Bishop |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 7, no. 1 ; Nr. 7, no. 1 (2007-01-24), S.89-101 |
| Datensatznummer |
250004330
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| Publikation (Nr.) |
 copernicus.org/nhess-7-89-2007.pdf |
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| Zusammenfassung |
| In February 2006, a disastrous rockslide-debris avalanche
occurred in tropical mountain terrain, on Leyte Island, Central Philippines.
Over 1100 people perished when the village of Guinsaugon was overwhelmed
directly in the path of the landslide. The landslide was initiated by the
failure of a 450 m high rock slope within the damage zone of the Philippine
Fault where the rock mass consisted of sheared and brecciated volcanic,
sedimentary and volcaniclastic rocks. Tectonic weakening of the failed rock
mass had resulted from active strike-slip movements along the Philippine
Fault which have been estimated by other workers at 2.5 cm/year. The
landslide involved a total volume of 15 Mm3, including significant
entrainment from its path, and ran out a horizontal distance of 3800 m over
a vertical distance of 810 m, equivalent to a fahrböschung of 12°.
Run-out distance was enhanced by friction reduction due to undrained loading
when the debris encountered flooded paddy fields in the valley bottom at a
path distance of 2600 m. A simulation of the event using the dynamic
analysis model DAN indicated a mean velocity of 35 m/s and demonstrated the
contribution of the paddy field effect to total run-out distance. There was
no direct trigger for the landslide but the landslide did follow a period of
very heavy rainfall with a lag time of four days. The rockslide-debris
avalanche is one of several disastrous landslides to have occurred in the
Philippines in the last twenty years. In terms of loss of life, the
Guinsaugon event is the most devastating single-event landslide to have
occurred worldwide since the Casita Volcano rock avalanche-debris flow which
was triggered by Hurricane Mitch in Nicaragua in 1998. |
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