scholarly journals INVESTIGATION OF DISTANCE MEASURING INDICES TO EXPRESS HANGING WALL EFFECT OF PEAK GROUND ACCELERATIONS IN NEAR SOURCE REGION OF REVERSE FAULT

2013 ◽  
Vol 78 (694) ◽  
pp. 2073-2082
Author(s):  
Atsushi MORIKAWA ◽  
Kenichi KATO ◽  
Tomonori IKEURA ◽  
Masayuki TAKEMURA ◽  
Atsushi Okazaki
Keyword(s):  
Hanging Wall ◽  
Source Region ◽  
Wall Effect ◽  
Reverse Fault ◽  
Peak Ground Accelerations ◽  
Hanging Wall Effect ◽  
Distance Measuring

Analysis of Strong Ground Motion Characterization in the 2013 Lushan Earthquake

2014 ◽  
Vol 580-583 ◽  
pp. 1499-1505 ◽  
Author(s):  
Tian Yu ◽  
Ming Lu ◽  
Xiao Jun Li
Keyword(s):  
Ground Motion ◽  
Hanging Wall ◽  
Lushan Earthquake ◽  
Wall Effect ◽  
Earthquake Ground Motion ◽  
Rupture Directivity ◽  
Directivity Effect ◽  
Rupture Area ◽  
Hanging Wall Effect ◽  
Rupture Distance

Lushan earthquake on 20th April, 2013 was another thrust fault earthquake occurred at Longmen Mountain Fault Zone after 2008 Wenchuan Ms8.0 earthquake. Based on ground motion attenuation model, this paper has chosen 45 strong motion records with rupture distance less than 200km, to analyze the hanging wall effect, topographic effect and rupture directivity effect of Lushan earthquake. The results show that hanging wall effect in Lushan earthquake was not obvious as 2008 Wenchuan earthquake; ground motion in mountain areas attenuated with increasing rupture distance more quickly than that in plain areas; rupture directivity effect is obvious for two components of horizontal ground motion, which are fault-perpendicular and fault-parallel components. PGA in the forward rupture area is larger than those in the backward rupture area. With the period increased, the gap between backward and forward rupture area become small, and finally PGD in backward rupture area is greater than those in the forward rupture area.

scholarly journals Near-Fault Ground Motion Influence on the Seismic Responses of a Structure with Viscous Dampers considering SSI Effect

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Jinping Yang ◽  
Peizhen Li ◽  
Hang Jing ◽  
Meng Gao
Keyword(s):  
Ground Motion ◽  
Hanging Wall ◽  
Wall Effect ◽  
Seismic Responses ◽  
Viscous Dampers ◽  
Directivity Effect ◽  
Near Fault ◽  
Forward Directivity ◽  
Hanging Wall Effect ◽  
Near Fault Ground Motion

This paper studies the influence of the characteristics of the near-fault ground motion on the seismic responses of the structure with energy dissipation devices including soil-structure interaction (SSI). A ten-story reinforced concrete frame rested on soft site is introduced, and the viscous dampers added in the frame are designed. The numerical analysis method of the soil-structure system with viscous dampers is established through ANSYS program. In addition, the response spectra of the main characteristics of the near-fault ground motion, like hanging wall effect, velocity pulse-like effect, and forward-directivity effect, are investigated carefully to learn the features of spectra energy distribution. And then, the dynamic time-history analysis is performed on the SSI system with and without viscous dampers subjected to the selected near-fault ground motion. The study reveals that the seismic responses of the structure subjected to near-fault ground motion with hanging wall effect are obviously larger than those of the footwall effect, indicating the distinct hanging wall effects on the structural dynamic responses. In addition, the performance of the structure with viscous dampers is more influenced by the ground motion containing fling-step effect than that with forward-directivity effect. Moreover, the influence of the horizontal component of forward-directivity ground motion on the seismic responses of the structure is more obvious than that of parallel component ground motion. Consequently, the hanging wall effect, velocity pulse, and horizontal component in forward-directivity effect of the near-fault ground motion have distinct influence on the seismic responses of the structure with energy dissipation devices considering SSI effect, providing insight towards the performance-based seismic design of buildings rested at the near-fault sites considering the seismic SSI effect.

Effects of the hanging wall and footwall on ground motions recorded during the Northridge earthquake

1996 ◽  
Vol 86 (1B) ◽  
pp. S93-S99
Author(s):  
N. A. Abrahamson ◽  
P. G. Somerville
Keyword(s):  
Ground Motion ◽  
Empirical Model ◽  
Empirical Data ◽  
Ground Motions ◽  
Hanging Wall ◽  
Systematic Difference ◽  
Wall Effect ◽  
Northridge Earthquake ◽  
Distance Range ◽  
Hanging Wall Effect

Abstract Systematic differences in ground motion on the hanging wall and footwall during the Northridge earthquake are evaluated using empirical data. An empirical model for the hanging-wall effect is developed for the Northridge earthquake. This empirical model results in up to a 50% increase in peak horizontal accelerations on the hanging wall over the distance range of 10 to 20 km relative to the median attenuation for the Northridge earthquake. In contrast, the peak accelerations on the footwall are not significantly different from the median attenuation over this distance range. Recordings from other reverse events show a similar trend of an increase in the peak accelerations on the hanging wall, indicating that this systematic difference in hanging-wall peak accelerations is likely to be observed in future reverse events.

scholarly journals Shaking Table Test On Dynamic Response of Bridge Pile Foundation Near Fault Under Strong Earthquake

2021 ◽  
Author(s):  
Cong Zhang ◽  
Zhong Ju Feng ◽  
Yuan Yuan Kong ◽  
Yun Hui Guan ◽  
Yun Xiu Dong ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Ground Motion ◽  
Pile Foundation ◽  
Strong Earthquake ◽  
Shaking Table Test ◽  
Hanging Wall ◽  
Shaking Table ◽  
Wall Effect ◽  
Hanging Wall Effect ◽  
Bridge Pile Foundation

Abstract Taking Puqian bridge as the prototype, a 1:30-scale pile-soil-fault interaction model was established. Through the shaking table test, the difference of dynamic response of pile foundation on both sides of fault under 0.15~0.60g ground motion intensity was studied. The pile acceleration, pile top relative displacement, and pile bending moment on both sides of the fault are compared respectively. Research results showed that under the action of a strong earthquake, the pile foundation on the hanging wall was greatly affected by ground motion, and “the hanging wall effect” was significant. As the ground motion intensity increased, the “hanging wall effect” of the pile foundation was more obvious. Combined with the fundamental frequency response and the test phenomenon, when ground motions intensity was strong, cracks appeared near the joint of pile top and platform, soil interface, and bedrock surface. When building a bridge pile foundation near the fault, the seismic design of the pile foundation on the hanging wall of the fault is mainly considered.

scholarly journals Numerical analysis of interseismic, coseismic and postseismic phases for normal and reverse faulting earthquakes in Italy

2020 ◽  
Author(s):  
Matteo Albano ◽  
Salvatore Barba ◽  
Christian Bignami ◽  
Eugenio Carminati ◽  
Carlo Doglioni ◽  
...  
Keyword(s):  
Seismic Waves ◽  
Hanging Wall ◽  
Normal Fault ◽  
Ground Subsidence ◽  
Reverse Fault ◽  
Fault Segment ◽  
Elastic Load ◽  
Reverse Faulting ◽  
Common Framework ◽  
Postseismic Relaxation

Summary The preparation, initiation, and occurrence dynamics of earthquakes in Italy are governed by several frequently unknown physical mechanisms and parameters. Understanding these mechanisms is crucial for developing new techniques and approaches for earthquake monitoring and hazard assessments. Here, we develop a first-order numerical model simulating quasi-static crustal interseismic loading, coseismic brittle episodic dislocations, and postseismic relaxation for extensional and compressional earthquakes in Italy based on a common framework of lithostatic and tectonic forces. Our model includes an upper crust, where the fault is locked, and a deep crust, where the fault experiences steady shear. The results indicate that during the interseismic phase, the contrasting behavior between the upper locked fault segment and lower creeping fault segment generates a stretched volume at depth in the hanging wall via extensional tectonics while a contracted volume forms via compressional tectonics. The interseismic stress and strain gradients invert at the coseismic stage, with the interseismic dilated volume contracting during the coseismic stage, and vice versa. Moreover, interseismic stress gradients promote coseismic gravitational subsidence of the hanging wall for normal fault earthquakes and elastic uplift for reverse fault earthquakes. Finally, the postseismic relaxation is characterized by further ground subsidence and uplift for normal and reverse faulting earthquakes, respectively, which is consistent with the faulting style. The fault is the passive feature, with slipping generating the seismic waves, whereas the energy activating the movement is stored mostly in the hanging wall volume. The main source of energy for normal faulting and thrust is provided by the lithostatic load and elastic load, respectively.

scholarly journals 3D Displacement Field of Wenchuan Earthquake Based on Iterative Least Squares for Virtual Observation and GPS/InSAR Observations

2020 ◽  
Vol 12 (6) ◽  
pp. 977
Author(s):  
Luyun Xiong ◽  
Caijun Xu ◽  
Yang Liu ◽  
Yangmao Wen ◽  
Jin Fang
Keyword(s):  
Wenchuan Earthquake ◽  
Displacement Field ◽  
Solution Method ◽  
Hanging Wall ◽  
Normal Fault ◽  
Strike Slip ◽  
Reverse Fault ◽  
Direct Solution ◽  
Maximum Displacement ◽  
Direct Solution Method

The acquisition of a 3D displacement field can help to understand the crustal deformation pattern of seismogenic faults and deepen the understanding of the earthquake nucleation. The data for 3D displacement field extraction are usually from GPS/interferometric synthetic aperture radar (InSAR) observations, and the direct solution method is usually adopted. We proposed an iterative least squares for virtual observation (VOILS) based on the maximum a posteriori estimation criterion of Bayesian theorem to correct the errors caused by the GPS displacement interpolation process. Firstly, in the simulation examples, both uniform and non-uniform sampling schemes for GPS observation were used to extract 3D displacement. On the basis of the experimental results of the reverse fault, the normal fault with a strike-slip component, and the strike-slip fault with a reverse component, we found that the VOILS method is better than the direct solution method in both horizontal and vertical directions. When a uniform sampling scheme was adopted, the percentages of improvement for the reverse fault ranged from 3% to 9% and up to 70%, for the normal fault with a strike-slip component ranging from 4% to 8% and up to 68%, and for the strike-slip fault with a reverse component ranging from 1% to 8% and up to 22%. After this, the VOILS method was applied to extract the 3D displacement field of the 2008 Mw 7.9 Wenchuan earthquake. In the East–West (E) direction, the maximum displacement of the hanging wall was 1.69 m and 2.15 m in the footwall. As for the North–South (N) direction, the maximum displacement of the hanging wall was 0.82 m for the southwestern, 0.95 m for the northeastern, while that of the footwall was 0.77 m. In the vertical (U) direction, the maximum uplift was 1.19 m and 0.95 m for the subsidence, which was significantly different from the direct solution method. Finally, the derived vertical displacements were also compared with the ruptures from field investigations, indicating that the VOILS method can reduce the impact of the interpolated errors on parameter estimations to some extent. The simulation experiments and the case study of the 3D displacement field for the 2008 Wenchuan earthquake suggest that the VOILS method proposed in this study is feasible and effective, and the degree of improvement in the vertical direction is particularly significant.

scholarly journals Onset of slip partitioning under oblique convergence within scaled physical experiments

Geosphere ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 875-889 ◽  
Author(s):  
Michele L. Cooke ◽  
Kevin Toeneboehn ◽  
Jennifer L. Hatch
Keyword(s):  
Hanging Wall ◽  
Strike Slip ◽  
Reverse Fault ◽  
Convergent Margins ◽  
Experimental Conditions ◽  
Multiple Faults ◽  
Strain Pattern ◽  
Oblique Convergence ◽  
Wide Range ◽  
Slip Partitioning

Abstract Oblique convergent margins host slip-partitioned faults with simultaneously active strike-slip and reverse faults. Such systems defy energetic considerations that a single oblique-slip fault accommodates deformation more efficiently than multiple faults. To investigate the development of slip partitioning, we record deformation throughout scaled experiments of wet kaolin over a low-convergence (<30°), obliquely slipping basal dislocation. The presence of a precut vertical weakness in the wet kaolin impacts the morphology of faults but is not required for slip partitioning. The experiments reveal three styles of slip partitioning development delineated by the order of faulting and the extent of slip partitioning. Low-convergence angle experiments (5°) produce strike-slip faults prior to reverse faults. In moderate-convergence experiments (10°–25°), the reverse fault forms prior to the strike-slip fault. Strike-slip faults develop either along existing weaknesses (precut or previous reverse-slip faults) or through the coalescence of new echelon cracks. The third style of local slip partitioning along two simultaneously active dipping faults is transient while global slip partitioning persists. The development of two active fault surfaces arises from changes in off-fault strain pattern after development of the first fault. With early strike-slip faults, off-fault contraction accumulates to produce a new reverse fault. Systems with early lobate reverse faults accommodate limited strike-slip and produce extension in the hanging wall, thereby promoting strike-slip faulting. The observation of persistent slip partitioning under a wide range of experimental conditions demonstrates why such systems are frequently observed in oblique convergence crustal margins around the world.

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