Hazard mapping related to structurally controlled landslides in Southern Leyte, Philippines
The 2006 Guinsaugon landslide in Saint Bernard, Southern Leyte, is one of the largest known landslides in the Philippines in recent history. It consists of a 15–20 million m<sup>3</sup> rockslide-debris avalanche from an approximately 675 m high mountain weakened by continuous movement o...
Main Authors: | , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-04-01
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Series: | Natural Hazards and Earth System Sciences |
Online Access: | http://www.nat-hazards-earth-syst-sci.net/16/875/2016/nhess-16-875-2016.pdf |
Summary: | The 2006 Guinsaugon landslide in Saint Bernard, Southern Leyte, is one of the
largest known landslides in the Philippines in recent history. It consists of
a 15–20 million m<sup>3</sup> rockslide-debris avalanche from an approximately
675 m high mountain weakened by continuous movement of the Philippine Fault.
The catastrophic Guinsaugon landslide killed 1221 people and displaced
19 000 residents over its 4.5 km path. To investigate the present-day
morphology of the scar and potential failure that may occur, analysis of a
5 m resolution InSAR-derived digital elevation model was conducted using
Coltop3D and Matterocking software, leading to the generation of a landslide
hazard map for the province of Southern Leyte in central Philippines. The dip
and dip direction of discontinuity sets that contribute to gravitational
failure in mountainous areas of the province were identified and measured
using a lower Schmidt–Lambert color scheme. After measurement of the
morpho-structural orientations, potential sites of failure were analyzed.
Conefall was then utilized to compute the extent of rock mass runout. Results
of the analysis show instability in the scarp area of the 2006 Guinsaugon
landslide and in adjacent slopes because of the presence of steep
discontinuities that range from 45 to 60°. Apart from the 2006
Guinsaugon landslide site, runout models simulated farther rock mass extent
in its adjacent slopes, revealing a high potential for fatal landslides to
happen in the municipality of Saint Bernard. Concerned agencies may use maps
produced in the same manner as this study to identify possible sites where
structurally controlled landslides can occur. In a country like the
Philippines, where fractures and faults are common, this type of simulated
hazard maps would be useful for disaster prevention and facilitate disaster
risk reduction efforts for landslide-susceptible areas. |
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ISSN: | 1561-8633 1684-9981 |