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| Titel |
Discrimination of hot versus cold avalanche deposits: Implications for hazard assessment at Mount Meager, B.C. |
| VerfasserIn |
M. L. Stewart, J. K. Russell, C. J. Hickson |
| 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 ; 3, no. 6 ; Nr. 3, no. 6, S.713-724 |
| Datensatznummer |
250001325
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| Publikation (Nr.) |
 copernicus.org/nhess-3-713-2003.pdf |
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| Zusammenfassung |
| The surficial
deposits surrounding the Mount Meager volcanic complex include numerous
avalanche deposits. These deposits share many attributes: (a) they are
nearly monolithologic and comprise mainly intermediate volcanic rock
clasts, (b) they lack internal structure, and (c) they are very poorly
sorted. Despite these similarities, the avalanche deposits represent two
distinct processes. Mass wasting of the Mount Meager volcanic edifice has
produced cold rock avalanche deposits, whereas gravitational collapse of
active lava domes and flows has produced hot block and ash avalanche
deposits. The ability to discriminate between these "hot" and
"cold" avalanche deposits is a critical component in the
assessment of hazards in volcanic terranes. Hot block and ash avalanche
deposits can be distinguished by the presence of radially-oriented joints,
breadcrust textures, and incipient welding, which are features indicative
of high emplacement temperatures. Conversely, rock avalanche deposits
resulting from mass wasting events may be distinguished by the presence of
clasts that preserve pre-depositional weathering and jointing surfaces.
Volcanic avalanches are mechanically similar to rock avalanches but pose a
greater hazard due to high temperatures, increased fluidization from
degassing and the potential to decouple highly mobile elutriated ash
clouds. The increasing use of hazardous regions such as the Lillooet River
valley requires more reliable risk assessment in order to minimize losses
from future hazardous events. |
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