Structural Properties and Deformation Patterns of Evolving Strike-slip Faults: Numerical Simulations Incorporating Damage Rheology

Knowledge from historical earthquake events indicates that a submarine tunnel crossing active strike-slip faults is prone to be damaged in an earthquake. Previous studies have demonstrated that the flexible joints are an effective measure for a submarine tunnel crossing a strike-slip fault. The background project of this paper is the second submarine tunnel of Jiaozhou bay. In this work, model tests and numerical simulations are conducted to investigate the deformation and failure mechanism of a submarine tunnel with flexible joints under a strike-slip fault dislocation. The influence of strike-slip faults on a tunnel with flexible joints has been investigated by examining the deformation of rock mass surface, analyzing lining stains, and crack propagation from model tests. Numerical simulations are conducted to study the effects of the design parameters of a tunnel with flexible joints on the mechanical response of the lining. The results showed that the ‘articulated design’ measure can improve the ability of the tunnel to resist the strike-slip faults. In terms of the mechanism of design parameters of a tunnel with flexible joints, this paper finds that increasing the lining thickness, decreasing the lining segment length, and decreasing the tunnel diameter to a reasonable extent could effectively improve the performance of this faulting resistance measure for a tunnel under the strike-slip fault zone dislocation. Compared with the horseshoe tunnel cross-section, the circular tunnel cross-section can improve the ability of the faulting resistance of a tunnel with flexible joints, while the optimal angle of the tunnel crossing the fault zone is 90º. It is concluded that the wider fault zone, smaller flexible joint width, and less stiffness of the flexible joint could make lining safer under a strike-slip fault dislocation. The above research results can serve as a necessary theoretical reference and technical support for the design of reinforcement measures for a submarine tunnel with flexible joints under strike-slip fault dislocation.

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Comparison of NGA-West2 Directivity Models

Earthquake Spectra ◽

10.1193/080313eqs222m ◽

2014 ◽

Vol 30 (3) ◽

pp. 1199-1221 ◽

Cited By ~ 35

Author(s):

Paul Spudich ◽

Badie Rowshandel ◽

Shrey K. Shahi ◽

Jack W. Baker ◽

Brian S.-J. Chiou

Keyword(s):

Numerical Simulations ◽

Narrow Band ◽

Scale Up ◽

Strike Slip ◽

Earthquake Magnitude ◽

Zero Level ◽

Geographic Distributions

Five directivity models have been developed based on data from the NGA-West2 database and based on numerical simulations of large strike-slip and reverse-slip earthquakes. All models avoid the use of normalized rupture dimension, enabling them to scale up to the largest earthquakes in a physically reasonable way. Four of the five models are explicitly “narrow-band” (in which the effect of directivity is maximum at a specific period that is a function of earthquake magnitude). Several strategies for determining the zero-level for directivity have been developed. We show comparisons of maps of the directivity amplification. This comparison suggests that the predicted geographic distributions of directivity amplification are dominated by effects of the models’ assumptions, and more than one model should be used for ruptures dipping less than about 65 degrees.

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New evidence for Cretaceous strike-slip faulting in the United States Cordillera and implications for terrane-displacement, deformation patterns, and plutonism

American Journal of Science ◽

10.2475/ajs.301.2.150 ◽

2001 ◽

Vol 301 (2) ◽

pp. 150-181 ◽

Cited By ~ 54

Author(s):

S. J. Wyld

Keyword(s):

United States ◽

The United States ◽

Strike Slip ◽

Deformation Patterns ◽

New Evidence

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Geometric Variation in the Surface Rupture of the 2018 Mw7.5 Palu Earthquake from Subpixel Optical Image Correlation

Remote Sensing ◽

10.3390/rs12203436 ◽

2020 ◽

Vol 12 (20) ◽

pp. 3436

Author(s):

Chenglong Li ◽

Guohong Zhang ◽

Xinjian Shan ◽

Dezheng Zhao ◽

Xiaogang Song

Keyword(s):

Shear Strain ◽

Surface Deformation ◽

Horizontal Displacement ◽

Strike Slip ◽

Image Correlation ◽

Displacement Fields ◽

Surface Rupture ◽

The North ◽

Deformation Patterns ◽

Geometric Variation

We obtained high-resolution (10 m) horizontal displacement fields from pre- and post-seismic Sentinel-2 optical images of the 2018 Mw7.5 Palu earthquake using subpixel image correlation. From these, we calculated the curl, divergence, and shear strain fields from the north-south (NS) and east-west (EW) displacement fields. Our results show that the surface rupture produced by the event was distributed within the Sulawesi neck (0.0974–0.6632°S) and Palu basin (0.8835–1.4206°S), and had a variable strike of 313.0–355.2° and strike slip of 2.00–6.62 m. The NS and EW displacement fields within the Palu basin included fine-scale displacements in both the near- and far-fault, the deformation patterns included a small restraining bend (localized shortening), a distributed rupture zone, and a major releasing bend (net extension) from the curl, divergence, and shear strain. Surface rupture was dominated by left-lateral strike-slip from initiation to termination, with a localized normal slip component peaking at ~3.75 m. The characteristics and geometric variation of the ruptured fault controlled both the formation of these surface deformation patterns and sustained supershear rupture.

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