scholarly journals The Effect of the Wenchuan and Lushan Earthquakes on the Size Distribution of Earthquakes along the Longmenshan Fault

2021 ◽  
Author(s):  
Chun Hui ◽  
Changxiu Cheng ◽  
Shi Shen ◽  
Peichao Gao ◽  
Jin Chen ◽  
...  
Keyword(s):  
Size Distribution ◽  
Stable State ◽  
B Value ◽  
Stable States ◽  
Seismicity Rate ◽  
Depth Images ◽  
Stress Changes ◽  
Longmenshan Fault ◽  
Time Required ◽  
Large Earthquakes

Abstract. Changes in the stress state of faults and their surroundings is a highly plausible mechanism explaining earthquakes interaction. These stress changes can impact the seismicity rate and the size distribution of earthquakes. However, the effect of large earthquakes on the earthquake size distribution along the Longmenshan fault has not been quantified. We evaluated the levels of the b value for the stable state before and after the large earthquakes on 12 May 2008 (Wenchuan, MS 8.0) and 20 April 2013 (Lushan, MS 7.0) along the Longmenshan fault. We found that after the mainshocks, the size distribution of the subsequent earthquakes shifted toward relatively larger events in the Wenchuan aftershock zone (b value decreased from 1.03 to 0.84), and generally remained invariable in the Lushan aftershock zone (b value remained at 0.76). The time required for the b value to return to stable states after both mainshocks were entirely consistent with the time needed by the aftershock depth images to stop visibly changing. The result of the temporal variation of b values show decreasing trends for the b value before both large earthquakes. Our results are available for assessing the potential seismic risk of the Longmenshan fault as a reference.

scholarly journals The Effect of the Wenchuan and Lushan Earthquakes on the Size Distribution of Earthquakes along the Longmenshan Fault

2021 ◽  
Vol 11 (18) ◽  
pp. 8534
Author(s):  
Chun Hui ◽  
Changxiu Cheng ◽  
Shi Shen ◽  
Peichao Gao ◽  
Jin Chen ◽  
...  
Keyword(s):  
Size Distribution ◽  
Stable State ◽  
B Value ◽  
Stable States ◽  
Seismicity Rate ◽  
Earthquake Interaction ◽  
Depth Images ◽  
Stress Changes ◽  
Longmenshan Fault ◽  
Large Earthquakes

Changes in the stress state of faults and their surroundings is a highly plausible mechanism explaining earthquake interaction. These stress changes can impact the seismicity rate and the size distribution of earthquakes. However, the effect of large earthquakes on the earthquake size distribution along the Longmenshan fault has not been quantified. We evaluated the levels of the b value for the stable state before and after the large earthquakes on 12 May 2008 (Wenchuan, MS 8.0) and 20 April 2013 (Lushan, MS 7.0) along the Longmenshan fault. We found that after the mainshocks, the size distribution of the subsequent earthquakes shifted toward relatively larger events in the Wenchuan aftershock zone (b value decreased from 1.21 to 0.84), and generally remained invariable in the Lushan aftershock zone (b value remained at 0.76). The time required for the b value to return to stable states after both mainshocks was entirely consistent with the time needed by the aftershock depth images to stop visibly changing. The result of the temporal variation of b values shows decreasing trends for the b value before both large earthquakes. Our results are available for assessing the potential seismic risk of the Longmenshan fault as a reference.

scholarly journals Path-dependent institutions drive alternative stable states in conservation

2018 ◽  
Vol 116 (2) ◽  
pp. 689-694 ◽  
Author(s):  
Edward W. Tekwa ◽  
Eli P. Fenichel ◽  
Simon A. Levin ◽  
Malin L. Pinsky
Keyword(s):  
Renewable Resources ◽  
Path Dependence ◽  
Alternative Stable States ◽  
Stable State ◽  
Empirical Support ◽  
Stable States ◽  
Alternative Stable State ◽  
Important Challenge ◽  
Quantitative Analyses ◽  
Path Dependent

Understanding why some renewable resources are overharvested while others are conserved remains an important challenge. Most explanations focus on institutional or ecological differences among resources. Here, we provide theoretical and empirical evidence that conservation and overharvest can be alternative stable states within the same exclusive-resource management system because of path-dependent processes, including slow institutional adaptation. Surprisingly, this theory predicts that the alternative states of strong conservation or overharvest are most likely for resources that were previously thought to be easily conserved under optimal management or even open access. Quantitative analyses of harvest rates from 217 intensely managed fisheries supports the predictions. Fisheries’ harvest rates also showed transient dynamics characteristic of path dependence, as well as convergence to the alternative stable state after unexpected transitions. This statistical evidence for path dependence differs from previous empirical support that was based largely on case studies, experiments, and distributional analyses. Alternative stable states in conservation appear likely outcomes for many cooperatively managed renewable resources, which implies that achieving conservation outcomes hinges on harnessing existing policy tools to navigate transitions.

scholarly journals Decomposing spatio-temporal seismicity patterns

2001 ◽  
Vol 1 (1/2) ◽  
pp. 83-92 ◽  
Author(s):  
C. Goltz
Keyword(s):  
Spatial And Temporal Variability ◽  
Seismicity Patterns ◽  
Seismicity Rate ◽  
Potential Applications ◽  
Time Series Approach ◽  
Distributed Process ◽  
Sample Application ◽  
Components Analysis ◽  
Spatio Temporal ◽  
Large Earthquakes

Abstract. Seismicity is a distributed process of great spatial and temporal variability and complexity. Efforts to characterise and describe the evolution of seismicity patterns have a long history. Today, the detection of changes in the spatial distribution of seismicity is still regarded as one of the most important approaches in monitoring and understanding seismicity. The problem of how to best describe these spatio-temporal changes remains, also in view of the detection of possible precursors for large earthquakes. In particular, it is difficult to separate the superimposed effects of different origin and to unveil the subtle (precursory) effects in the presence of stronger but irrelevant constituents. I present an approach to the latter two problems which relies on the Principal Components Analysis (PCA), a method based on eigen-structure analysis, by taking a time series approach and separating the seismicity rate patterns into a background component and components of change. I show a sample application to the Southern California area and discuss the promising results in view of their implications, potential applications and with respect to their possible precursory qualities.

scholarly journals Bachatskiy induced earthquake on June 18, 2013, ML=6.1, I0=7 (Kuzbass)

2020 ◽  
Vol 2 (1) ◽  
pp. 48-61 ◽  
Author(s):  
Aleksandr Emanov ◽  
Aleksey Emanov ◽  
Aleksandr Fateev
Keyword(s):  
B Value ◽  
Mountain Area ◽  
Seismic Arrays ◽  
Seismic Activation ◽  
Background Seismicity ◽  
Single Process ◽  
Strip Mine ◽  
Large Earthquakes ◽  
Sayan Mountain ◽  
Natural Seismicity

The Bachatsky earthquake of 18 June 2013 and a seismic activation of the same name coal strip mine, started several years before the earthquake and still persists today, have been studied using temporal local seismic arrays in the area. It was found experimentally that the seismic process area is closely connected to open workings, and the earthquakes are extend-ed from the working bed to a depth of 4-5 km. Adjacent to the mine depression sedimentary rocks were activated. The technogenic seismic regime is continuous and not stationary: intervals of background seismicity with relatively weak and seldom events are disturbed by bursts of activity with a rise in the magnitude of stronger earthquakes and frequency of occurrence of weak events. The seismic activation may last for 1–3 months. During the last five years, four seismic activations have been recorded, three of which were generated by large earthquakes of 09.02.2012, ML4.3; 04.03.2013, ML3.9; 18.06.2013, ML6.1. The last one was completed by a series of perceptible earthquakes with local magnitude of 3.0–3.5. The focal mechanism of the Bachatsky earthquake is a thrust fault with one of the motion planes corresponding to the anthropogenic impact. The earthquake flow forms a single process in the space with the b-value of the Gutenberg-Richter relationship different from the natural seismicity. The studied induced seismicity does not correspond to the structural regularities of natural seismicity in the Altai-Sayan mountain area. The findings prove that the Bachatsky earthquake and associated activation can be considered as man-made events.

Design and Characterization of Single Beam for Latching Electrothermal Microswitch

2012 ◽  
Vol 468-471 ◽  
pp. 286-289
Author(s):  
Ying Zhang ◽  
Hong Wang ◽  
Yan Wang ◽  
Sheng Ping Mao ◽  
Gui Fu Ding
Keyword(s):  
Mechanical Performance ◽  
Stable State ◽  
Cantilever Beams ◽  
Analysis Software ◽  
Stable States ◽  
Element Analysis ◽  
Single Beam ◽  
Fabrication And Characterization ◽  
Continuous Power

This paper presents the design, fabrication and characterization of single beam for latching electrothermal microswitch. This microswitch consists of two cantilever beams using bimorph electrothermal actuator with mechanical latching for performing low power bistable relay applications. A stable state can be acquired without continuous power which is only needed to switch between two stable states of the microactuator. The single beam is discussed mainly to judge the possibility of realizing the designed function. First, reasonable shape of the resistance is designed using finite element analysis software ANSYS. Then, mechanical performance was characterized by WYKO NT1100 optical profiling system, the tip deflection of single beam can meet the designed demand.

Distinct tectonic activities in Guangxi, China due to large earthquakes on the Longmenshan fault zone

2020 ◽  
Vol 307 ◽  
pp. 106557
Author(s):  
Huaizhong Yu ◽  
Jing Zhao ◽  
Xiaoxia Liu ◽  
Chen Yu ◽  
Chong Yue ◽  
...  
Keyword(s):  
Fault Zone ◽  
Longmenshan Fault Zone ◽  
Longmenshan Fault ◽  
Large Earthquakes ◽  
Tectonic Activities

Automated modal parameters identification of bistable composite plate using two-stage clustering of operational modal testing

2020 ◽  
pp. 002199832090308
Author(s):  
Mahdi Ghamami ◽  
Hassan Nahvi ◽  
Vahid Yaghoubi
Keyword(s):  
Analytical Method ◽  
Composite Plate ◽  
Ritz Method ◽  
Stable State ◽  
User Interaction ◽  
Modal Testing ◽  
Modal Parameters ◽  
Identification Algorithm ◽  
Stable States ◽  
Modal Parameters Identification

In recent years, smart structures have attracted much interest as morphing structures. One of the simplest types of these structures is bistable composite plate, which has many applications in aerospace, structures, actuators, etc. On the other hand, inverse problem theory provides conceptual ideas and methods for the practical solution of applied problems. These methods are opposite of the forward problem and define a model of the system based on output or observations. In this paper, a modified identification algorithm is used to determine the modal parameters of a bistable composite plate based on vibrational signals. Both analytical and experimental approaches have been considered and analytical method has been used to investigate the accuracy of identification algorithm, which has been performed based on experimental measurement. In the analytical method, static and free vibration behaviors of a cross-ply bistable composite plate are studied by the Hamilton's principle and the Rayleigh–Ritz method. The experimental approach is performed by an operational modal testing, which is a nondestructive test. The identification process does not require user interaction and the process uses only a single dataset and there is no need to repeat the test or data collection. The advantages of the proposed algorithm is the ability to determine the modal parameters of each stable state with high accuracy and robustness. A comparison of the natural frequencies shows that the identification of both stable states has been successful and the estimated modal parameters are in good agreement with the analytical and experimental results.

scholarly journals A Nonvolatile Fractional Order Memristor Model and its Complex Dynamics

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 955 ◽  
Author(s):  
Wu ◽  
Wang ◽  
Iu ◽  
Shen ◽  
Zhou
Keyword(s):  
Fractional Order ◽  
Complex Dynamics ◽  
Equilibrium Points ◽  
Stable State ◽  
Electrical Characteristics ◽  
Chaotic Circuit ◽  
Stable States ◽  
Road Map ◽  
Chaotic Circuits ◽  
Integral Order

It is found that the fractional order memristor model can better simulate the characteristics of memristors and that chaotic circuits based on fractional order memristors also exhibit abundant dynamic behavior. This paper proposes an active fractional order memristor model and analyzes the electrical characteristics of the memristor via Power-Off Plot and Dynamic Road Map. We find that the fractional order memristor has continually stable states and is therefore nonvolatile. We also show that the memristor can be switched from one stable state to another under the excitation of appropriate voltage pulse. The volt–ampere hysteretic curves, frequency characteristics, and active characteristics of integral order and fractional order memristors are compared and analyzed. Based on the fractional order memristor and fractional order capacitor and inductor, we construct a chaotic circuit, of which the dynamic characteristics with respect to memristor’s parameters, fractional order α, and initial values are analyzed. The chaotic circuit has an infinite number of equilibrium points with multi-stability and exhibits coexisting bifurcations and coexisting attractors. Finally, the fractional order memristor-based chaotic circuit is verified by circuit simulations and DSP experiments.

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