Physical modeling experiments to study periodic activation of faults in seismic zones

Our study aimed to find a mechanism that controls preparation and subsequent full seismic activation of large faults that may act as sources of strong earthquakes. A large fault was physically modeled to investigate the dynamics of its deformation. The experiments were conducted on elastoviscoplasti...

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Main Authors: S. A. Bornyakov, I. A. Panteleev, A. V. Cheremnykh, A. A. Karimova
Format: Article
Language:English
Published: Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust 2018-10-01
Series:Геодинамика и тектонофизика
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Online Access:https://www.gt-crust.ru/jour/article/view/619
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author S. A. Bornyakov
I. A. Panteleev
A. V. Cheremnykh
A. A. Karimova
author_facet S. A. Bornyakov
I. A. Panteleev
A. V. Cheremnykh
A. A. Karimova
author_sort S. A. Bornyakov
collection DOAJ
description Our study aimed to find a mechanism that controls preparation and subsequent full seismic activation of large faults that may act as sources of strong earthquakes. A large fault was physically modeled to investigate the dynamics of its deformation. The experiments were conducted on elastoviscoplastic and elastic models of the lithosphere. A digital camera was used to capture images in the course of the modeling experiments. The digital image correlation method (DIC) detected the moments of impulse activation and displacements along the entire fault or its major segment. Between the activation moments, the fault structure consists of segments, including active ones. Activation is directional and involves a few large segments of the fault, then numerous small ruptures, and the latter are gradually degenerating. The long-term deformation dynamics of the fault is represented by a regular sequence of its full activations. In most cases, each moment of activation correlates with a minimum dip angle of the repeatability curve (β) and a maximum value of information entropy (Si). We analysed in detail the deformation dynamics of the fault and in its wings between two full activation that occurred in a regular pattern, including the phases of regression and progression of the deformation process. The analysis revealed two similar scenarios in the evolution of the active segments and plastic micro slip faults within the active segments. In some intervals of time, deformation takes place considerably differently on the segments and the plastic micro slip faults. Such differences suggest that in the studies attempting to statistically predict and assess a large and potentially seismically hazardous fault zone, this zone should be considered spatially subdivided into a central narrow subzone (including the main fault plane) and two wide subzones framing the fault wings. According to our physical modeling results, the central subzone can be up to10 km wide, and the total width of all the subzones can amount to100 km or more. This study contributes to the development of the concepts of geodynamics of large faults in the seismic zones of the lithosphere and investigates one of the possible mechanisms preparing strong earthquakes in the seismic zones.
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spelling doaj-art-54d8b3ef5f9344c7a7617e53703dde562025-08-20T03:44:07ZengRussian Academy of Sciences, Siberian Branch, Institute of the Earth's crustГеодинамика и тектонофизика2078-502X2018-10-019365367010.5800/GT-2018-9-3-0366363Physical modeling experiments to study periodic activation of faults in seismic zonesS. A. Bornyakov0I. A. Panteleev1A. V. Cheremnykh2A. A. Karimova3Institute of the Earth's Crust, Siberian Branch of RAS; Irkutsk State UniversityInstitute of Continuous Media Mechanics, Ural Branch of RASInstitute of the Earth's Crust, Siberian Branch of RASInstitute of the Earth's Crust, Siberian Branch of RAS; Irkutsk State UniversityOur study aimed to find a mechanism that controls preparation and subsequent full seismic activation of large faults that may act as sources of strong earthquakes. A large fault was physically modeled to investigate the dynamics of its deformation. The experiments were conducted on elastoviscoplastic and elastic models of the lithosphere. A digital camera was used to capture images in the course of the modeling experiments. The digital image correlation method (DIC) detected the moments of impulse activation and displacements along the entire fault or its major segment. Between the activation moments, the fault structure consists of segments, including active ones. Activation is directional and involves a few large segments of the fault, then numerous small ruptures, and the latter are gradually degenerating. The long-term deformation dynamics of the fault is represented by a regular sequence of its full activations. In most cases, each moment of activation correlates with a minimum dip angle of the repeatability curve (β) and a maximum value of information entropy (Si). We analysed in detail the deformation dynamics of the fault and in its wings between two full activation that occurred in a regular pattern, including the phases of regression and progression of the deformation process. The analysis revealed two similar scenarios in the evolution of the active segments and plastic micro slip faults within the active segments. In some intervals of time, deformation takes place considerably differently on the segments and the plastic micro slip faults. Such differences suggest that in the studies attempting to statistically predict and assess a large and potentially seismically hazardous fault zone, this zone should be considered spatially subdivided into a central narrow subzone (including the main fault plane) and two wide subzones framing the fault wings. According to our physical modeling results, the central subzone can be up to10 km wide, and the total width of all the subzones can amount to100 km or more. This study contributes to the development of the concepts of geodynamics of large faults in the seismic zones of the lithosphere and investigates one of the possible mechanisms preparing strong earthquakes in the seismic zones.https://www.gt-crust.ru/jour/article/view/619physical modelingfaultsegmentationseismogenic activation
spellingShingle S. A. Bornyakov
I. A. Panteleev
A. V. Cheremnykh
A. A. Karimova
Physical modeling experiments to study periodic activation of faults in seismic zones
Геодинамика и тектонофизика
physical modeling
fault
segmentation
seismogenic activation
title Physical modeling experiments to study periodic activation of faults in seismic zones
title_full Physical modeling experiments to study periodic activation of faults in seismic zones
title_fullStr Physical modeling experiments to study periodic activation of faults in seismic zones
title_full_unstemmed Physical modeling experiments to study periodic activation of faults in seismic zones
title_short Physical modeling experiments to study periodic activation of faults in seismic zones
title_sort physical modeling experiments to study periodic activation of faults in seismic zones
topic physical modeling
fault
segmentation
seismogenic activation
url https://www.gt-crust.ru/jour/article/view/619
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AT iapanteleev physicalmodelingexperimentstostudyperiodicactivationoffaultsinseismiczones
AT avcheremnykh physicalmodelingexperimentstostudyperiodicactivationoffaultsinseismiczones
AT aakarimova physicalmodelingexperimentstostudyperiodicactivationoffaultsinseismiczones