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Titel |
Review Article: Potential geomorphic consequences of a future great (Mw = 8.0+) Alpine Fault earthquake, South Island, New Zealand |
VerfasserIn |
T. R. Robinson, T. R. H. Davies |
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 ; 13, no. 9 ; Nr. 13, no. 9 (2013-09-23), S.2279-2299 |
Datensatznummer |
250085515
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Publikation (Nr.) |
copernicus.org/nhess-13-2279-2013.pdf |
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Zusammenfassung |
The Alpine Fault in New Zealand's South Island has not sustained a large
magnitude earthquake since ca. AD 1717. The time since this rupture is close
to the average inferred recurrence interval of the fault (~300 yr). The Alpine Fault is therefore expected to generate a large
magnitude earthquake in the near future. Previous ruptures of this fault are
inferred to have generated Mw = 8.0 or greater earthquakes and to
have resulted in, amongst other geomorphic hazards, large-scale landslides
and landslide dams throughout the Southern Alps. There is currently 85%
probability that the Alpine Fault will cause a Mw = 8.0+ earthquake within the next 100 yr. While the seismic hazard is fairly
well understood, that of the consequential geomorphic activity is less
well studied, and these consequences are explored herein. They are expected
to include landsliding, landslide damming, dam-break flooding, debris flows,
river aggradation, liquefaction, and landslide-generated lake/fiord tsunami.
Using evidence from previous events within New Zealand as well as analogous
international examples, we develop first-order estimates of the likely
magnitude and possible locations of the geomorphic effects associated with
earthquakes. Landsliding is expected to affect an area
> 30 000 km2 and involve > 1billion m3 of material.
Some tens of landslide dams are expected to occur in narrow, steep-sided
gorges in the affected region. Debris flows will be generated in the first
long-duration rainfall after the earthquake and will continue to occur for
several years as rainfall (re)mobilises landslide material. In total more
than 1000 debris flows are likely to be generated at some time after the
earthquake. Aggradation of up to 3 m will cover an area
> 125 km2 and is likely to occur on many West Coast alluvial fans
and floodplains. The impact of these effects will be felt across the entire
South Island and is likely to continue for several decades. |
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