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| Titel |
Amalgamation in landslide maps: effects and automatic detection |
| VerfasserIn |
O. Marc, N. Hovius |
| 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 Sciences ; 15, no. 4 ; Nr. 15, no. 4 (2015-04-02), S.723-733 |
| Datensatznummer |
250119413
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| Publikation (Nr.) |
 copernicus.org/nhess-15-723-2015.pdf |
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| Zusammenfassung |
| Inventories of individually delineated landslides are a key to understanding
landslide physics and mitigating their impact. They permit assessment of
area–frequency distributions and landslide volumes, and testing of
statistical correlations between landslides and physical parameters such as
topographic gradient or seismic strong motion. Amalgamation, i.e. the mapping
of several adjacent landslides as a single polygon, can lead to potentially
severe distortion of the statistics of these inventories. This problem can be
especially severe in data sets produced by automated mapping. We present five
inventories of earthquake-induced landslides mapped with different materials
and techniques and affected by varying degrees of amalgamation. Errors on the
total landslide volume and power-law exponent of the area–frequency
distribution, resulting from amalgamation, may be up to 200 and 50%,
respectively. We present an algorithm based on image and digital elevation model (DEM) analysis, for
automatic identification of amalgamated polygons. On a set of about 2000
polygons larger than 1000 m2, tracing landslides triggered by the 1994
Northridge earthquake, the algorithm performs well, with only 2.7–3.6%
incorrectly amalgamated landslides missed and 3.9–4.8% correct polygons
incorrectly identified as amalgams. This algorithm can be used broadly to check
landslide inventories and allow faster correction by automating the
identification of amalgamation. |
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