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| Titel |
Drainage basin morphometry controls on the active depositional area of debris flow fans |
| VerfasserIn |
Monika Mihir, Thad Wasklewicz, Bruce Malamud |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250112077
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| Publikation (Nr.) |
 EGU/EGU2015-12233.pdf |
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| Zusammenfassung |
| A majority of the research on understanding the connection between alluvial fans and
drainage basins to date has focused on coarse-scale relations between total fan area and
drainage basin area. Here we take a new approach where we assess relationships between
active fan depositional area and drainage basin morphometry using 52 debris flow fans (32
from the White Mountains and 20 from the Inyo Mountains) on the eastern side
of Owens Valley, California, USA. The boundaries for fans, drainage basin and
active depositional areas were delineated from 10m digital elevation models and 1 m
aerial photographs. We examined the relationships between the normalised active
depositional area of the fan (Afad/Af, where Afad is the fan active depositional area
and Af the entire fan area) and the following four variables for drainage basin: (i)
area (Adb), (ii) total stream length (Ls), (iii) relief (BHH), (iv) roughness (R).
We find a statistically significant (r2 > 0.40) inverse power-law relationship
between recent sediment contribution to the fan and drainage basin area (Afad/Af =
0.29Adb-0.167) drainage network length (Afad/Af = 0.39Ls-0.161) and basin relief
(Afad/Af = 3.90BHH-0.401), and a statistically weak (r2 = 0.22) inverse power law
with basin roughness (Afad/Af = 0.32R0.5441). Drainage basin size combined
with other morphometric variables may largely determine efficiency in sediment
transport and delivery to the fan surface. A large proportion of the total fan area
of smaller fans are flooded by debris flow indicating less sediment storage in the
drainage basins and greater efficiency in sediment delivery. The findings signify the
importance of coarse-scale relationships to both long- and short-term fan evolution. |
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