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| Titel |
The long runout of the Heart Mountain landslide: A chemo-thermo-poro-elastic mechanism |
| VerfasserIn |
Liran Goren, Einat Aharonov, Mark H. Anders |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040759
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| Zusammenfassung |
| The Eocene age Heart Mountain landslide in northwestern Wyoming is the largest subaerial
landslide known. This slide is an extreme example of a long runout with upper plate blocks
that slid up to 50 km along a slope with an average dip of 2-. The emplacement mechanism
of this unique structure has long been an enigma. Here we suggest that a combination of a
thermo-poro-elastic (TPE) feedback operating along the slide base, and thermal
decomposition of carbonates on the sliding surface, may explain the Heart Mountain
landslide via a catastrophic emplacement mechanism. TPE effects arise when a porous,
fluid-filled, shear zone undergoes frictional heating during sliding. If the shear zone is
confined, heating will cause pore pressure to rise, which in turn will reduce frictional
resistance to sliding. Pore pressure diffusion from the shear zone (via porous flow) opposes
this process. The shear zone of the Heart Mountain slide is located within a confined dolomite
layer, ideal location for the TPE mechanism. Due to high heating rates the temperature
along the slide base is expected to rise rapidly and reach the temperature of thermal
decomposition of carbonates. This endothermic reaction further complicates the TPE
feedback by consuming heat, increasing porosity, and releasing CO2. Simulation of
the sliding dynamics of the Heart Mountain block, accounting both for the TPE
feedback and for thermal decomposition of carbonates, successfully reproduces
the travel distance of the Heart Mountain block. This simulation also predicts that
the maximum sliding velocity was 113 m/s, and sliding duration was 26 minutes. |
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