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| Titel |
About the Possibility Of Transformation Of Shear Deformation Modes. |
| VerfasserIn |
Aleksey Ostapchuk, Gevorg Kocharyan, Dmitriy Pavlov, Vadim Markov |
| 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 |
250094247
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| Publikation (Nr.) |
 EGU/EGU2014-9647.pdf |
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| Zusammenfassung |
| In this study we present the results of laboratory experiments aimed to investigate the effect
of material properties, filling a discontinuity, on transformation of deformation modes from
stable creep to regular stick-slip. Qualitative correspondence between experimental results
and natural phenomena is detected.
The experiments were carried out in the classical “slider model” statement. A small
granite block slid under shear load on a bigger granite block. The contact between rough
surfaces of the blocks was filled with a discrete material, which simulated the fault
zone. Quartz sand, granite crumb, glass balls and rock salt were used as the filling
material. The normal load was applied to the sliding block through a special device
excluding origination of tangential forces. Shear load was applied to the block through a
spring. The sliding block position was controlled by laser sensors that recorded
relative displacement of blocks at the frequency up to 4 kHz with the accuracy of 0.1
micron.
A full spectrum of possible deformation regimes was obtained in experiments - from
stable slip to low-velocity motion and to regular stick-slip, with various seismic moments
realized per one act of instability. The deformation regime can transform into another one
due to a slight change of the filling material structure and humidity. Experimental
data can be divided into three groups, which, speaking in terms of seismology,
correspond to aseismic creep, slow earthquakes and normal earthquakes with various
magnitudes.
Laboratory experiments allowed to determine the main factor that controlls realization of
deformation regime of the model fault and to develop the phenomenological model of the
process based on assumption that some force mesostructures were forming across the model
fault in shearing. The mode of deformation regime is completely controlled by the length and
amount of these mesostructures. At the same time narrow particle-size distribution, high
degree of order of the filling material and strong interaction between grains also contribute to
origination of force mesostructures.
The study was supported by the Russian Foundation for Basic Research, projects
13-05-00780, 13-05-00950. |
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