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| Titel |
Are large submarine landslides in Polar Regions temporally random, or do current observations and age constraint make it impossible to tell? |
| VerfasserIn |
Ed Pope, Peter Talling, Morelia Urlaub, James Hunt, Mike Clare, Peter Challenor |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093249
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| Publikation (Nr.) |
 EGU/EGU2014-7818.pdf |
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| Zusammenfassung |
| Submarine landslides are one of the major mechanisms through which sediment is
transported across our planet, and it has been proposed that they can generate exceptionally
damaging tsunamis. Polar margins represent one of the environmental settings where these
events have been identified. A large number of triggers and preconditioning factors have been
proposed as possible causes for these events; including earthquakes, rapid sedimentation and
gas hydrate dissociation. Rapid climate change in the Arctic has the potential to impact on
these preconditioning and triggering factors. First, crustal rebound associated with ice
melting is likely to produce larger and more frequent earthquakes. Second, Arctic Ocean
warming over the next few decades may lead to dissociation of methane hydrates in
marine sediments, thereby weakening sediment. In order to better understand whether
landslide frequency will increase in the future, we need to determine whether landslide
frequency has been affected by previous episodes of rapid climate or eustatic sea level
change.
Previous working whether landslide frequency is affected strongly by climatic change has
been based predominantly on qualitative analysis, and has concluded that event clustering has
occurred under specific environmental conditions. In contrast, two recent statistical
investigations of submarine landslides have found events frequencies to follow a
Poissonian distribution and thus are temporally random (Urlaub et al, 2013, QSR;
Clare et al., Geology, Vol 42 (3)). However, these recent studies acknowledge the
significant uncertainties in most landslide dates, and that these uncertainties could mask
underlying relationships with climate or sea level. This presentation extends previous
statistical work to assess whether landslide frequency is most likely temporally
random, or whether the dating is just too uncertain to tell. Chi-Squared statistics
are used to explore the extent to which we can be statistically sure that submarine
landslides do indeed follow a Poissonian distribution. This is achieved by analysing the
ease with which ordered frequency data can appear Poissonian according to the
Chi-Squared statistic and the number of events needed before a certain distribution can be
guaranteed. From this we are able comment on the extent to which we can use event
frequency as a means with which to analyse triggers and preconditioning factors.
We can also assess the implications for future submarine landslide risk analysis. |
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