The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
Anne-marie Boullier - One of the best experts on this subject based on the ideXlab platform.
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Fault-zone geology: lessons from drilling through the Nojima and Chelungpu faults
Geological Society London Special Publications, 2011Co-Authors: Anne-marie BoullierAbstract:Several drilling projects have been conducted through active faults with the aim of learning about the geology of the fault zones and tentatively correlating the structure and mineralogy of the fault zones with their seismological behaviour during recent Earthquakes. Here we present the major results obtained from structural and mineralogical studies of core samples retrieved from the dextral reverse strike-slip Nojima Fault (Japan) within granitic rocks following the Kobe Earthquake (1995), and from the Chelungpu Thrust Fault (Taiwan) within alternating silts and shales following the Chi-chi Earthquake (1999). We show how these projects, despite not fullfilling all their objectives, have still contributed to a better geological knowledge of the fault zones, to a better characterization of the slip zones related to the recent Earthquakes particularly of their thickness, microstructures and deformation mechanisms, and to a better understanding of the nature and role of fluids within the fault zone. They have also led to new questions, and to new approaches, for studying fault-rock samples. For all of these reasons, they have stimulated international scientific research into fault-zone geology.
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2008Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:International audienceFourier transform infrared (FTIR) micro-analysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt% of the wall rock CO2 content. Carbon is exsolved because it is upersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 103 tons CO2 within a few seconds. This extraordinary release of CO2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2007Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:Abstract Fourier transform infrared (FTIR) microanalysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt.% of the wall rock CO 2 content. Carbon is exsolved because it is supersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 10 3 tons CO 2 within a few seconds. This extraordinary release of CO 2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults.
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Textural evidence for recent co-seismic circulation of fluids in the Nojima fault zone, Awaji island, Japan
Tectonophysics, 2003Co-Authors: Anne-marie Boullier, Koichiro Fujimoto, Tomoyuki Ohtani, Gabriela Roman-ross, Eric Lewin, Hisao Ito, Philippe Pezard, Benoit IldefonseAbstract:Abstract The Hirabayashi borehole (Awaji Island, Japan) was drilled by the Geological Survey of Japan (GSJ) 1 year after the Hyogo-ken Nanbu (Kobe) Earthquake (1995, MJMA=7.2). This has enabled scientists to study the complete sequence of deformation across the active Nojima fault, from undeformed granodiorite to the fault core. In the fault core, different types of gouge and fractures have been observed and can be interpreted in terms of a complex history of faulting and fluid circulation. Above the fault core and within the hanging wall, compacted cataclasites and gouge are cut by fractures which show high apparent porosity and are filled by 5–50 μm euhedral and zoned siderite and ankerite crystals. These carbonate-filled fractures have been observed within a 5.5-m-wide zone above the fault, but are especially abundant in the vicinity (1 m) of the fault. The log-normal crystal size distributions of the siderite and ankerite suggest that they originated by decaying-rate nucleation accompanied by surface-controlled growth in a fluid saturated with respect to these carbonates. These carbonate-filled fractures are interpreted as the result of co-seismic hydraulic fracturing and upward circulation of fluids in the hanging wall of the fault, with the fast nucleation of carbonates attributed to a sudden fluid or CO2 partial pressure drop due to fracturing. The fractures cut almost all visible structures at a thin section scale, although in some places, the original idiomorphic shape of carbonates is modified by a pressure-solution mechanism or the carbonate-filled fractures are cut and brecciated by very thin gouge zones; these features are attributed to low and high strain-rate mechanisms, respectively. The composition of the present-day groundwater is at near equilibrium or slightly oversaturated with respect to the siderite, calcite, dolomite and rhodochrosite. Taken together, this suggests that these fractures formed very late in the evolution of the fault zone, and may be induced by co-seismic hydraulic fracturing and circulation of a fluid with a similar composition to the present-day groundwater. They are therefore potentially related to recent Earthquake activity (
Tetsuro Hirono - One of the best experts on this subject based on the ideXlab platform.
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2008Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:International audienceFourier transform infrared (FTIR) micro-analysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt% of the wall rock CO2 content. Carbon is exsolved because it is upersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 103 tons CO2 within a few seconds. This extraordinary release of CO2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2007Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:Abstract Fourier transform infrared (FTIR) microanalysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt.% of the wall rock CO 2 content. Carbon is exsolved because it is supersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 10 3 tons CO 2 within a few seconds. This extraordinary release of CO 2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults.
Koichiro Fujimoto - One of the best experts on this subject based on the ideXlab platform.
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2008Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:International audienceFourier transform infrared (FTIR) micro-analysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt% of the wall rock CO2 content. Carbon is exsolved because it is upersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 103 tons CO2 within a few seconds. This extraordinary release of CO2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2007Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:Abstract Fourier transform infrared (FTIR) microanalysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt.% of the wall rock CO 2 content. Carbon is exsolved because it is supersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 10 3 tons CO 2 within a few seconds. This extraordinary release of CO 2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults.
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Textural evidence for recent co-seismic circulation of fluids in the Nojima fault zone, Awaji island, Japan
Tectonophysics, 2003Co-Authors: Anne-marie Boullier, Koichiro Fujimoto, Tomoyuki Ohtani, Gabriela Roman-ross, Eric Lewin, Hisao Ito, Philippe Pezard, Benoit IldefonseAbstract:Abstract The Hirabayashi borehole (Awaji Island, Japan) was drilled by the Geological Survey of Japan (GSJ) 1 year after the Hyogo-ken Nanbu (Kobe) Earthquake (1995, MJMA=7.2). This has enabled scientists to study the complete sequence of deformation across the active Nojima fault, from undeformed granodiorite to the fault core. In the fault core, different types of gouge and fractures have been observed and can be interpreted in terms of a complex history of faulting and fluid circulation. Above the fault core and within the hanging wall, compacted cataclasites and gouge are cut by fractures which show high apparent porosity and are filled by 5–50 μm euhedral and zoned siderite and ankerite crystals. These carbonate-filled fractures have been observed within a 5.5-m-wide zone above the fault, but are especially abundant in the vicinity (1 m) of the fault. The log-normal crystal size distributions of the siderite and ankerite suggest that they originated by decaying-rate nucleation accompanied by surface-controlled growth in a fluid saturated with respect to these carbonates. These carbonate-filled fractures are interpreted as the result of co-seismic hydraulic fracturing and upward circulation of fluids in the hanging wall of the fault, with the fast nucleation of carbonates attributed to a sudden fluid or CO2 partial pressure drop due to fracturing. The fractures cut almost all visible structures at a thin section scale, although in some places, the original idiomorphic shape of carbonates is modified by a pressure-solution mechanism or the carbonate-filled fractures are cut and brecciated by very thin gouge zones; these features are attributed to low and high strain-rate mechanisms, respectively. The composition of the present-day groundwater is at near equilibrium or slightly oversaturated with respect to the siderite, calcite, dolomite and rhodochrosite. Taken together, this suggests that these fractures formed very late in the evolution of the fault zone, and may be induced by co-seismic hydraulic fracturing and circulation of a fluid with a similar composition to the present-day groundwater. They are therefore potentially related to recent Earthquake activity (
Vincent Famin - One of the best experts on this subject based on the ideXlab platform.
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2008Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:International audienceFourier transform infrared (FTIR) micro-analysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt% of the wall rock CO2 content. Carbon is exsolved because it is upersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 103 tons CO2 within a few seconds. This extraordinary release of CO2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults
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Earthquakes produce carbon dioxide in crustal faults
Earth and Planetary Science Letters, 2007Co-Authors: Vincent Famin, Satoru Nakashima, Anne-marie Boullier, Koichiro Fujimoto, Tetsuro HironoAbstract:Abstract Fourier transform infrared (FTIR) microanalysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that Earthquakes almost instantaneously expel 99 wt.% of the wall rock CO 2 content. Carbon is exsolved because it is supersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe Earthquake (1995) may yield a total production of 1.8 to 3.4 × 10 3 tons CO 2 within a few seconds. This extraordinary release of CO 2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance Earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large Earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults.
Arup Bhattacharjee - One of the best experts on this subject based on the ideXlab platform.
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Numerical Simulation of Tiered Reinforced Soil Retaining Wall Subjected to Dynamic Excitations
Lecture Notes in Civil Engineering, 2020Co-Authors: Seema Kumari, Arup BhattacharjeeAbstract:This paper presents the study carried out to analyze the response of multitiered reinforced earth walls with vertical (zero-tier) subjected to seismic/dynamic excitations. Plaxis 2D is a finite element program accomplishes the analysis of RE walls in different conditions. A numerical approach is selected to examine the safety of RE walls during dynamic excitation of 0.4 g Kobe Earthquake (1995) and results of the response spectrum of finite element models are compared with the result of shake table test. A two-tiered RE wall of height nine meters designed as per FHWA (2010) is simulated using the different parameters of validated model. The lateral displacements of facing, maximum reinforcement load and acceleration amplification factor of wall without offset and two-tiered walls are compared.
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Effect of Offset Distance on Tiered Reinforced Soil Retaining Wall Subjected to Dynamic Excitation
Innovative Infrastructure Solutions using Geosynthetics, 2019Co-Authors: Sudipta Sikha Saikia, Arup BhattacharjeeAbstract:The rapid growth in urbanization and demand for effective space lead to increase in application of geosynthetic reinforced soil (GRS) retaining walls in major infrastructure project like flyover etc. The researchers have conducted physical, analytical and numerical studies on performance of single tiered and multi-tiered reinforced soil wall and compared the responses. The study of multi-tiered GRS wall has not achieved the growth as the single tiered GRS wall due to its limited application. The objective of this paper is to understand the response of tiered reinforced soil retaining wall subjected to dynamic excitation. This paper emphasizes on comparative study of response of multi-tiered reinforced soil walls with single- tiered reinforced soil wall subjected to seismic excitations. A 2.8 m high finite element model of modular block facing reinforced soil wall is simulated using finite element software PLAXIS 2D. The numerical model is subjected to dynamic excitations of 0.4 g Kobe Earthquake and results of the response of the numerical model are validated with shake table tests results of Ling et al. (2005). The two and three tiered walls of 9 m height with different offset distances of 0.75 m, 1.5 m and 3.0 m are simulated with validated model parameters. The construction sequence is followed in numerical model simulation and model is brought to equilibrium condition after each stage of construction. The acceleration histories of Kobe Earthquake (1995) having PGA 0.4 g is applied at the base of all models. The variation of horizontal displacements, lateral pressures, maximum reinforcement loads and acceleration amplification factors of single tiered and multi-tiered walls with various offset distances are compared. It is found from the analyses that the horizontal deformation, acceleration amplification factor and maximum reinforcement load decreases with the increasing tier offset.
