Microstructure and geochemistry of pseudotachylyte veins from Sarwar‐Junia Fault Zone, India: Implications for frictional melting process in a seismic fault zone

Finite elements analysis is a powerful tool, often used for analyzing problems on stress, that can be successfully employed to analyze the finite deformation of geological structures in a mathematical form on a digital computer. Over the last century, great earthquakes with magnitudes of 7->8 have struck in the NW Himalaya; the 1905 Kangra earthquake is one of them. This study performed a plane strain analysis of failure stress and faults in these earthquakes potential region based on the seismic geologic cross profile employing the two-dimensional finite element method under elastic material state with Mohr Coulomb failure criterion. The results show that the normal fault initiates at deeper level, whereas with increasing convergent displacement the thrust fault appears in the shallower region. The results of the simulation are compared with the available seismic and earthquakes focal mechanism solution data of the area which shows the close similarities between the distribution of simulated fault and microseismicity in the deeper region of Chamba Nappe (CN) and along the upper part of the Mid Crustal Ramp (MCR) which might be the Seismic Fault Zone (SFZ) of the region. Moreover, the intense localization of faults along the frontal part of the model indicates that this part is active in nature at present, which is responsible for the neotectonics in the Himalayas. Keywords: NW Himalaya; numerical technique; seismic fault zone; neotectonics DOI: 10.3329/jles.v2i2.7499 J. Life Earth Sci., Vol. 2(2) 57-65, 2007

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Response Analysis of Bridge across Seismic Fault Zone

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.178-181.2224 ◽

2012 ◽

Vol 178-181 ◽

pp. 2224-2227

Author(s):

Qi Zhen Li ◽

Hong Quan Li ◽

Zhi Qian Zhang

Keyword(s):

Fault Zone ◽

Bridge Pier ◽

Additional Stress ◽

Response Analysis ◽

Geological Condition ◽

Structure Model ◽

Bridge Structure ◽

Continuous Beam ◽

Seismic Fault ◽

Deformation Law

Through simulating the happening location of the fault zone, the structure model is duly simplified, analysing the forced deformation law of the bridge surface with different fault zone position. Because of statically indeterminate structure, continuous beam shall be produced larger additional moment, shear force and torque as a result of displacement in bridge pier, additional stress will be increased with the the increasement of fault zone displacement, especially for the top surface parts of bridge pier. Hence, the corresponding position of the structure and construction measures for reinforcement should strengthened, the overall rigidity of the structure should be improved, and based on the study of the bridge across the fault zone is a simplified, and the actual stress process may be more complex, the investigation on geological condition must be clear, and avoid the bridge structure crossing fault zone.

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Quantitative analysis of seismic fault zone waves in the rupture zone of the 1992 Landers, California, earthquake: evidence for a shallow trapping structure

Geophysical Journal International ◽

10.1111/j.1365-246x.2003.02109.x ◽

2003 ◽

Vol 155 (3) ◽

pp. 1021-1041 ◽

Cited By ~ 104

Author(s):

Zhigang Peng ◽

Yehuda Ben-Zion ◽

Andrew J. Michael ◽

Lupei Zhu

Keyword(s):

Quantitative Analysis ◽

Fault Zone ◽

Rupture Zone ◽

Seismic Fault ◽

Fault Zone Waves

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High-resolution Imaging of Fault Zone Structures with Seismic Fault Zone Waves

Scientific Drilling ◽

10.5194/sd-specialissue-78-2007 ◽

2007 ◽

Vol SpecialIssue ◽

pp. 78-79 ◽

Cited By ~ 1

Author(s):

Y. Ben-Zion ◽

Z. Peng ◽

M. Lewis ◽

J. McGuire

Keyword(s):

High Resolution ◽

Fault Zone ◽

High Resolution Imaging ◽

Seismic Fault ◽

Resolution Imaging ◽

Fault Zone Structures ◽

Fault Zone Waves

No abstract available. doi:<a href="http://dx.doi.org/10.2204/iodp.sd.s01.23.2007" target="_blank">10.2204/iodp.sd.s01.23.2007</a>

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Seismic fault zone trapped noise

Journal of Geophysical Research Solid Earth ◽

10.1002/2014jb011217 ◽

2014 ◽

Vol 119 (7) ◽

pp. 5786-5799 ◽

Cited By ~ 22

Author(s):

G. Hillers ◽

M. Campillo ◽

Y. Ben-Zion ◽

P. Roux

Keyword(s):

Fault Zone ◽

Seismic Fault

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Field and experimental evidence of frictional melting in fluid-rich faults

10.5194/egusphere-egu2020-7425 ◽

2020 ◽

Author(s):

Giulio Di Toro ◽

Michele Fondriest ◽

Tom Mitchell ◽

Rodrigo Gomila ◽

Erik Jensen ◽

...

Keyword(s):

Experimental Evidence ◽

Continental Crust ◽

Fault Zone ◽

Damage Zone ◽

Fault System ◽

Common Belief ◽

Pressurized Water ◽

Geological Record ◽

Seismic Slip ◽

Frictional Melting

Pseudotachylytes (solidified friction melts produced during seismic slip) are considered to be rare in the geological record because they should be typical of particular seismogenic environments characterized by water-deficient cohesive rocks. Here we present field and experimental evidence that frictional melting can occur in &#8220;fluid-rich&#8221; faults hosted in the continental crust.Pseudotachylytes were found in the >40 km long Bolfin Fault Zone of the Atacama Fault System (Northern Chile). The pseudotachylytes (1) are associated with a ~1 m thick ultracataclastic fault core which accommodated > 5 km of strike-slip displacement at 6-8 km depth and 280-350&#176;C ambient temperature, (2) cut a ca. 50 m thick damage zone made of sub-greenschists facies hydrothermally altered diorites and gabbros, (3) cut and are cut by epidote+chlorite+calcite bearing veins. The microstructure of the pseudotachylytes include (1) tabular microlites of feldspar hosted in a glassy-like matrix and (2) vesicles filled by post-seismic sub-greenschist facies minerals hosted in a strongly altered matrix of albite, chlorite, and epidote crystals.Experiments reproducing seismic slip in the presence of pressurized water and conducted with the rotary shear apparatus SHIVA on experimental faults made of the sub-greenschists (hydrothermally altered) facies damage zone rocks from the Bolfin Fault Zone, resulted in the production of vesiculated pseudotachylytes. In these experiments, fault weakening mainly occurred by melt lubrication rather than by pore fluid thermal pressurization.The identification of pseudotachylytes and its association with intense pre- and post-seismic hydrothermal alteration challenges the common belief that pseudotachylytes are rare. Consistent with the experimental evidence, pseudotachylytes (1) could be a common coseismic fault product in the continental crust, (2) may easily be produced in fluid-rich hydrothermal environments but, (3) are easily lost from the geological record because they are prone to alteration.

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Analyzing Seismic Destructive Effect to the Submarine Rock and Soil Layers According to Submarine Seismic Records

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.166-169.2494 ◽

2012 ◽

Vol 166-169 ◽

pp. 2494-2506

Author(s):

Bang Hua Zhang ◽

Hong Shui Tian

Keyword(s):

Fault Zone ◽

Tensile Deformation ◽

Seismic Action ◽

Destructive Effect ◽

Soil Layers ◽

Seismic Fault ◽

Seismic Records ◽

Marine Facies ◽

Combined Action ◽

Rock And Soil

By means of survey and study, various submarine seismic records were identified in the marine facies strata from Sinian Period to Ordovician Period in Tancheng-Lujiang seismic fault zone and its vicinity. These submarine seismic records are divided into two classes. According to the mode of seismic action, every class of submarine seismic records is divided into three to four types. On the basis of classification, this paper studied and summarized seismic destructive effects to the submarine rock and soil layers and diagrammatized mechanism and process of seismic destructive effects. Seismic destructive effects to soft sedimentary soil strata mainly include seismic vibratory liquefaction, vibratory thixotropic effect, seismic fold deformation, sliding deformation, tensile deformation and combined action of shaking and weight. Seismic destructive effects to submarine soil strata of semi-consolidated to un-completely consolidated sediments mainly include syn-sedimentary fault effect, crack and smashing effect, filling effect of seismic crack, etc.

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