scholarly journals Effects of Barriers on Fault Rupture Process and Strong Ground Motion Based on Various Friction Laws

2020 ◽  
Vol 10 (5) ◽  
pp. 1687
Author(s):  
Jie Yuan ◽  
Jinting Wang ◽  
Shoubiao Zhu
Keyword(s):  
Total Duration ◽  
Propagation Speed ◽  
Propagation Distance ◽  
Rupture Process ◽  
Fault Rupture ◽  
Ground Acceleration ◽  
Fault Surface ◽  
Friction Laws ◽  
Simulation Results ◽  
Rupture Speed

A barrier may induce a supershear rupture on a fault. This paper focuses on two questions: One is whether the existence of a barrier accelerates the propagation speed of a whole fault rupture, and the other is what are the effects of friction laws and strength of a barrier on the rupture propagation process. For these purposes, classical slip-weakening, rate-state, and modified slip-weakening friction laws are employed to simulate the effect of a barrier on the fault rupture process. The simulation results showed that the rupture speed of the fault obviously decreases when the rupture front propagates to the barriers, and the rupture speed obviously increases when the rupture front leaves barriers. It was also found that a barrier on a fault may induce a supershear rupture via the rate-state friction law. The simulation results also showed that with the increase of barrier strength, the rupture speed near barriers fluctuates more and more; when the barrier strength exceeds a certain level, a supershear rupture area appears on the fault; with the increase of barrier strength, the propagation distance of the rupture at supershear wave velocity correspondingly increases. In addition, with the increase of barrier strength, the overall rupture duration of the fault slightly increases. This indicates that a barrier cannot shorten the total duration of a fault rupture. Though a barrier will lead to a supershear rupture, it just regulates the distribution of the rupture speed on the fault surface. Moreover, with the increase of barrier strength, the peak ground acceleration caused by rupture through the barrier also increases, indicating that the existence of a barrier may lead to the intensification of seismic hazards.

Effect of Finite Diaphragm Rupture Process on Microshock Tube Flows

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Arun K. R ◽  
H. D. Kim ◽  
T. Setoguchi
Keyword(s):  
Supersonic Flow ◽  
Flow Field ◽  
Shock Front ◽  
Supersonic Nozzle ◽  
Propagation Speed ◽  
Propagation Distance ◽  
Rupture Process ◽  
Shock Propagation ◽  
Diaphragm Rupture ◽  
Contact Distance

The study of flow physics in microshock tubes is of growing importance with the recent development of microscale technology. The flow characteristics in a microshock tube is considerably different from that of the conventional macroshock tube due to the boundary layer effects and high Knudsen number effects. In the present study an axisymmetric computational fluid dynamics (CFD) method was employed to simulate the microshock tube flow field with Maxwell's slip velocity and temperature jump boundary conditions, to accommodate the rarefaction effects. The effects of finite diaphragm rupture process and partial diaphragm rupture on the flow field and the wave propagations were investigated, in detail. The results show that the shock propagation distance attenuates rapidly for a microshock tube compared to a macroshock tube. For microshock tubes, the contact surface comes closer to the shock front compared to the analytical macroshock tube case. Due to the finite diaphragm rupture process the moving shock front will be generated after a certain distance ahead of the diaphragm and get attenuated rapidly as it propagates compared to the sudden rupture case. The shock-contact distance reduces considerably for the finite diaphragm rupture case compared to the sudden diaphragm rupture process. A partially burst diaphragm within a microshock tube initiates a supersonic flow in the vicinity of the diaphragm similar to that of a supersonic nozzle flow. The supersonic flow expansion leads to the formation of oblique shock cells ahead of the diaphragm and significantly attenuates the moving shock propagation speed.

Source dynamics of the 1979 Imperial Valley earthquake from near-source observations (of ground acceleration and velocity)

1982 ◽  
Vol 72 (6A) ◽  
pp. 1957-1968
Author(s):  
Mansour Niazi
Keyword(s):  
Particle Acceleration ◽  
Particle Velocity ◽  
High Frequency ◽  
Observation Point ◽  
P Wave ◽  
Imperial Valley ◽  
Ground Acceleration ◽  
Data Set ◽  
Ground Shaking ◽  
Fault Surface

abstract Two sets of observations obtained during the 15 October 1979 Imperial Valley earthquake, MS 6.9, are presented. The data suggest different dynamic characteristics of the source when viewed in different frequency bands. The first data set consists of the observed residuals of the horizontal peak ground accelerations and particle velocity from predicted values within 50 km of the fault surface. The residuals are calculated from a nonlinear regression analysis of the data (Campbell, 1981) to the following empirical relationships, PGA = A 1 ( R + C 1 ) − d 1 , PGV = A 2 ( R + C 2 ) − d 2 in which R is the closest distance to the plane of rupture. The so-calculated residuals are correlated with a positive scalar factor signifying the focusing potential at each observation point. The focusing potential is determined on the basis of the geometrical relation of the station relative to the rupture front on the fault plane. The second data set consists of the acceleration directions derived from the windowed-time histories of the horizontal ground acceleration across the El Centro Differential Array (ECDA). The horizontal peak velocity residuals and the low-pass particle acceleration directions across ECDA require the fault rupture to propagate northwestward. The horizontal peak ground acceleration residuals and the high-frequency particle acceleration directions, however, are either inconclusive or suggest an opposite direction for rupture propagation. The inconsistency can best be explained to have resulted from the incoherence of the high-frequency radiation which contributes most effectively to the registration of PGA. A test for the sensitivity of the correlation procedure to the souce location is conducted by ascribing the observed strong ground shaking to a single asperity located 12 km northwest of the hypocenter. The resulting inconsistency between the peak acceleration and velocity observations in relation to the focusing potential is accentuated. The particle velocity of Delta Station, Mexico, in either case appears abnormally high and disagrees with other observations near the southeastern end of the fault trace. From the observation of a nearly continuous counterclockwise rotation of the plane of P-wave particle motion at ECDA, the average rupture velocity during the first several seconds of source activation is estimated to be 2.0 to 3.0 km/sec. A 3 km upper bound estimate of barrier dimensions is tentatively made on the basis of the observed quasiperiodic variation of the polarization angles.

Numerical Modeling of Near Fault Seismic Ground Motion for Denali Fault

2021 ◽  
Vol 12 (2) ◽  
pp. 0-0
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Numerical Study ◽  
Ground Motions ◽  
Numerical Results ◽  
Fault Rupture ◽  
Ground Acceleration ◽  
Denali Fault ◽  
Near Fault ◽  
Good Agreement

An effective earthquake (Mw 7.9) struck Alaska on 3 November, 2002. This earthquake ruptured 340 km along Susitna Glacier, Denali and Totschunda faults in central Alaska. The peak ground acceleration (PGA) was recorded about 0.32 g at station PS10, which was located 3 km from the fault rupture. The PGA would have recorded a high value, if more instruments had been installed in the region. A numerical study has been conducted to find out the possible ground motion record that could occur at maximum horizontal slip during the Denali earthquake. The current study overcomes the limitation of number of elements to model the Denali fault. These numerical results are compared with observed ground motions. It is observed that the ground motions obtained through numerical analysis are in good agreement with observed ground motions. From numerical results, it is observed that the possible expected PGA is 0.62 g at maximum horizontal slip of Denali fault.

ANALISIS PENERAPAN SISTEM PENJADWALAN DENGAN METODE PERT PADA PROYEK KONSTRUKSI (STUDI KASUS: REHABILITASI DAN PENINGKATAN INFRASTRUKSI PASAR TRADISONAL KOTA MALANG)

2021 ◽  
Vol 14 (2) ◽  
pp. 19
Author(s):  
Faris Rizal Andardi
Keyword(s):  
Completion Time ◽  
Total Duration ◽  
Infrastructure Projects ◽  
Scheduling System ◽  
Project Completion ◽  
Traditional Market ◽  
Simulation Results ◽  
Market Infrastructure

PERT is a simplified software, to produce the expected project completion probability based on the duration or duration of a particular contract. In developing the PERT method a lot of research was carried out to perfect this method. The purpose of this study is to determine the overall duration of project completion, the magnitude of the project probability that can be completed in less than 170 days and more than 170 days, and the project completion time with the highest probability. Results of Analysis of Implementation of Scheduling System with PERT Method in Rehabilitation and Improvement of Traditional Market Infrastructure Projects in Malang City is the total duration of simulation results obtained 168 days faster than the 172 day plan. The probability of completing the 168 day project is 50%, while the probability of completing the 172 day project is 85.31%. The highest chance of the project being completed is 99.97%, with a duration of 181 days.

Risk Management of Construction Schedule by PERT with Monte Carlo Simulation

2014 ◽  
Vol 548-549 ◽  
pp. 1646-1650 ◽  
Author(s):  
Yang Liu ◽  
Yan Li
Keyword(s):  
Sensitivity Analysis ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Critical Path ◽  
Total Duration ◽  
Control Points ◽  
Schedule Management ◽  
Simulation Results ◽  
Critical Paths ◽  
Construction Schedule

It has been proved that the construction schedule management was an uncertain problem. Traditional CPM method was a good way to define the total duration and critical paths but can not solve uncertainty. The paper use CPM to define the duration and critical path firstly, then defined the parameters with Delphi and make Monte Carlo simulation. Through simulation results, it is found that the probability to finish the work on time was only 35.3%. The following step is to make sensitivity analysis, through the calculation, the work which has large influence was found and treat as key control points. It is proved that Monte Carlo simulation is useful to solve the problem of construction schedule management.

scholarly journals Mechanism Reduction and Bunsen Burner Flame Verification of Methane

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 97
Author(s):  
Haitao Lu ◽  
Fuqiang Liu ◽  
Yulan Wang ◽  
Xiongjie Fan ◽  
Jinhu Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Laminar Flame ◽  
Propagation Speed ◽  
Bunsen Burner ◽  
Important Species ◽  
Jet Flame ◽  
Reduced Mechanism ◽  
Ignition Delay Times ◽  
Simulation Results ◽  
Propagation Methods

Based on directed relation graph with error propagation methods, 39 species and 231 reactions skeletal mechanism were obtained from Mech_56.54 (113 species and 710 reactions) mechanism of methane. The ignition delay times, laminar flame propagation speed, and important species were calculated using the simplified mechanism at different pressures and equivalence ratios. The simulation results were in good agreement with that of detailed mechanisms and experimental data. The numerical simulation of the Bunsen burner jet flame was carried out using the simplified methane mechanism, and the simulation results well reproduced the temperature, flow fields and distribution of important species at flame zone. The compact methane reduced mechanism can not only correctly respond to its dynamic characteristics, but also can be well used for numerical simulation, which is of great significance in engineering applications.

The Morgan Hill Earthquake of April 24, 1984—The 1.29g Acceleration at Coyote Lake Dam: Due to Directivity, a Double Event, or Both?

1985 ◽  
Vol 1 (3) ◽  
pp. 445-455 ◽  
Author(s):  
Norman A. Abrahamson ◽  
Robert B. Darragh
Keyword(s):  
Spatial Variation ◽  
High Frequency ◽  
Seismic Source ◽  
Fault Rupture ◽  
Constructive Interference ◽  
Ground Acceleration ◽  
Field Station ◽  
S Waves ◽  
Broadband Seismograms ◽  
Double Event

The 1984 Halls Valley (Morgan Hill, California) earthquake had a complex seismic source. Velocities of the major seismic phases measured from continuous broadband seismograms at Berkeley Seismographic Station (BKS) and Richmond Field Station (RFS) show unambiguously that the earthquake is predominantly a double event with the second source hypocenter located approximately 17 km southeast of the mainshock hypocenter given by Bolt, Uhrhammer and Darragh (1985). The southeasterly fault rupture of the first source and the location of the focus of the second source have critical implications for the observed spatial variation of the recorded accelerograms. Of particular engineering interest, the high frequency 1.29g pulse of horizontal ground acceleration measured at Coyote Lake dam can be explained primarily as due to the second source and constructive interference of the principal S waves from the two sources.

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