Publication Date:
2012
abstract:
In August 2009, in Taiwan, Typhoon Morakot, characterized by a cumulative rainfall up to 3000 mm in about three
days, triggered thousands of landslides and debris flows, and according to government reports, more than 600
people were dead or missing, and the economic loss was estimated at hundreds million of USD. The availability
of detailed LiDAR surveys before and after this relevant event offers a great opportunity to deeply investigate the
topographic signatures of a major typhoon, thus providing a way to better understand the earth surface processes
and the landscape evolution in a region affected by these phenomena, and where the uplift rate is significant. We
considered 11 small catchments with an area ranging from 0.9 5.1 km2, located in the Southern Taiwan, affected
by a different degree of erosion (totally affected by significant landslides and not affected by any erosion) during
the Typhoon Morakot. For each of these catchment 1 m Digital Terrain Model (DTM) was derived by LiDAR data,
before and after Morakot, for a total of 22 high resolution DTMs. Different analyses were then carried out: we
considered the spatial distribution of curvature and roughness index of residual topography. The results indicate
that catchments deeply affected by the typhoon present: i) a significant evidence of landform curvature and ii)
surface roughness changes based on statistics. The possibility to make these analysis and obtain these information,
immediately after an intense event, really represent a strategic tool for a first quantification of the processes that
affected and significantly changed the earth surface, and provide a quick preliminary view on which part of the
investigated landscape is more affected by these processes.
days, triggered thousands of landslides and debris flows, and according to government reports, more than 600
people were dead or missing, and the economic loss was estimated at hundreds million of USD. The availability
of detailed LiDAR surveys before and after this relevant event offers a great opportunity to deeply investigate the
topographic signatures of a major typhoon, thus providing a way to better understand the earth surface processes
and the landscape evolution in a region affected by these phenomena, and where the uplift rate is significant. We
considered 11 small catchments with an area ranging from 0.9 5.1 km2, located in the Southern Taiwan, affected
by a different degree of erosion (totally affected by significant landslides and not affected by any erosion) during
the Typhoon Morakot. For each of these catchment 1 m Digital Terrain Model (DTM) was derived by LiDAR data,
before and after Morakot, for a total of 22 high resolution DTMs. Different analyses were then carried out: we
considered the spatial distribution of curvature and roughness index of residual topography. The results indicate
that catchments deeply affected by the typhoon present: i) a significant evidence of landform curvature and ii)
surface roughness changes based on statistics. The possibility to make these analysis and obtain these information,
immediately after an intense event, really represent a strategic tool for a first quantification of the processes that
affected and significantly changed the earth surface, and provide a quick preliminary view on which part of the
investigated landscape is more affected by these processes.
Iris type:
04.02 - Abstract in atti di convegno
List of contributors:
Tseng, C‐m; Tarolli, Paolo; Lin, C. W.
Published in: