scholarly journals Large earthquake cycles and intermittent criticality on heterogeneous faults due to evolving stress and seismicity

2003 ◽  
Vol 108 (B6) ◽  
Author(s):  
Yehuda Ben-Zion ◽  
Mariana Eneva ◽  
Yunfeng Liu
Keyword(s):  
Large Earthquake ◽  
Earthquake Cycles ◽  
Intermittent Criticality

Rate and State Seismicity Simulations for Large Earthquake Cycles in Western Taiwan

2020 ◽  
Author(s):  
Hung-Yu Wu ◽  
Kuo-Fong Ma ◽  
Bill Fry
Keyword(s):  
Stress State ◽  
Slip Rate ◽  
Large Earthquake ◽  
Initial Stresses ◽  
Fault System ◽  
Recurrence Time ◽  
Seismic Events ◽  
Earthquake Catalog ◽  
Initial Stress State ◽  
Earthquake Cycles

<p>The stress state variation during the fault rupturing is the key issue for the earthquake hazard. However, the modern seismic catalogs exist the huge gap of large earthquake recurrence records. To understand the occurrence, the probabilities and the dynamic processing of large earthquakes, we employed the multi-cycle earthquake simulator, RSQSim, to exam the fundamental aspects of seismicity distribution in spatial and time in western Taiwan. This 3D, boundary element software assembles the Rate and State Friction law (RSF) and initial stress state to simulate the earthquakes distributions in completely, complex seismogenic system. The heterogeneous initial stresses and recurrence seismic events would be estimated in the long sequences. In this research, we focus on the similarity comparison to the CWB earthquake catalog and Taiwan Earthquake Model (TEM) for the RSQSim simulations. Additionally, this information provides the near optimal nucleation locations and seismic events propagation at the stress evolution in Taiwan faulting systems. Through this process, we would like to examine the recurrence time of the significant earthquakes in western Taiwan. RSQsim results include the comprehensive large events in temporal series to understand the key discrepancy between models and simulators, which will bring the mutual input to TEM for update discussion on slip rate, stress accumulation, and fault system. These modifications provide the better understanding of faults slip and stress state evolution to support the fundamental aspects of earthquake cycles.</p>

scholarly journals Nowcasting Earthquakes in Sulawesi Island, Indonesia

2020 ◽  
Author(s):  
Sumanta Pasari ◽  
Andrean VH Simanjuntak ◽  
Yogendra Sharma
Keyword(s):  
Large Earthquake ◽  
Earthquake Hazard ◽  
Earthquake Hazards ◽  
Power Law Distribution ◽  
Probability Models ◽  
Current State ◽  
Natural Time ◽  
Earthquake Hazard Assessment ◽  
Assessment Techniques ◽  
Earthquake Cycles

Abstract Large devastating events such as earthquakes often display frequency-magnitude statistics that exhibit power-law distribution. In this study, we implement a new method of nowcasting (Rundle et al. 2016) to evaluate the current state of earthquake hazards in the seismic prone Sulawesi province, Indonesia. The nowcasting technique considers statistical behavior of small event counts, known as natural times, to infer the seismic progression of large earthquake cycles in a defined region. To develop natural time statistics in the Sulawesi Island, we employ four probability models, namely exponential, exponentiated exponential, gamma, and Weibull distribution. Statistical inference of natural times reveals that (i) exponential distribution has the best representation to the observed data; (ii) estimated nowcast scores (%) corresponding to M≥6.5 events for 21 cities are Bau-bau (41), Bitung (70), Bone (44), Buton (39), Donggala (63), Gorontalo (49), Kendari (27), Kolaka (30), Luwuk (56), Makassar (52), Mamuju (58), Manado (70), Morowali (37), Palopo (34), Palu (62), Pare-pare (82), Polewali (61), Poso (42), Taliabu (55), Toli-toli (58), and Watampone (55); and (iii) the results are broadly consistent to the changes of magnitude threshold and area of local regions. Therefore, the present nowcasting analysis, similar to the traditional earthquake hazard assessment techniques, offers a simple yet versatile metric to the scientists, engineers and policymakers to examine the current state of earthquake hazards in the thickly populated Sulawesi Island.

scholarly journals Real-time automatic uncertainty estimation of coseismic single rectangular fault model using GNSS data

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Keitaro Ohno ◽  
Yusaku Ohta ◽  
Satoshi Kawamoto ◽  
Satoshi Abe ◽  
Ryota Hino ◽  
...  
Keyword(s):  
Real Time ◽  
Disaster Response ◽  
Order Approximation ◽  
Nonlinear Problems ◽  
Large Earthquake ◽  
Fault Model ◽  
Deformation Monitoring ◽  
Model Parameters ◽  
The Sea Of Japan ◽  
Plate Interface

AbstractRapid estimation of the coseismic fault model for medium-to-large-sized earthquakes is key for disaster response. To estimate the coseismic fault model for large earthquakes, the Geospatial Information Authority of Japan and Tohoku University have jointly developed a real-time GEONET analysis system for rapid deformation monitoring (REGARD). REGARD can estimate the single rectangular fault model and slip distribution along the assumed plate interface. The single rectangular fault model is useful as a first-order approximation of a medium-to-large earthquake. However, in its estimation, it is difficult to obtain accurate results for model parameters due to the strong effect of initial values. To solve this problem, this study proposes a new method to estimate the coseismic fault model and model uncertainties in real time based on the Bayesian inversion approach using the Markov Chain Monte Carlo (MCMC) method. The MCMC approach is computationally expensive and hyperparameters should be defined in advance via trial and error. The sampling efficiency was improved using a parallel tempering method, and an automatic definition method for hyperparameters was developed for real-time use. The calculation time was within 30 s for 1 × 106 samples using a typical single LINUX server, which can implement real-time analysis, similar to REGARD. The reliability of the developed method was evaluated using data from recent earthquakes (2016 Kumamoto and 2019 Yamagata-Oki earthquakes). Simulations of the earthquakes in the Sea of Japan were also conducted exhaustively. The results showed an advantage over the maximum likelihood approach with a priori information, which has initial value dependence in nonlinear problems. In terms of application to data with a small signal-to-noise ratio, the results suggest the possibility of using several conjugate fault models. There is a tradeoff between the fault area and slip amount, especially for offshore earthquakes, which means that quantification of the uncertainty enables us to evaluate the reliability of the fault model estimation results in real time.

scholarly journals Stress relaxation arrested the mainshock rupture of the 2016 Central Tottori earthquake

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Yoshihisa Iio ◽  
Satoshi Matsumoto ◽  
Yusuke Yamashita ◽  
Shin’ichi Sakai ◽  
Kazuhide Tomisaka ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Focal Mechanism ◽  
Large Earthquake ◽  
Static Stress ◽  
Focal Mechanism Solutions ◽  
Large Earthquakes

AbstractAfter a large earthquake, many small earthquakes, called aftershocks, ensue. Additional large earthquakes typically do not occur, despite the fact that the large static stress near the edges of the fault is expected to trigger further large earthquakes at these locations. Here we analyse ~10,000 highly accurate focal mechanism solutions of aftershocks of the 2016 Mw 6.2 Central Tottori earthquake in Japan. We determine the location of the horizontal edges of the mainshock fault relative to the aftershock hypocentres, with an accuracy of approximately 200 m. We find that aftershocks rarely occur near the horizontal edges and extensions of the fault. We propose that the mainshock rupture was arrested within areas characterised by substantial stress relaxation prior to the main earthquake. This stress relaxation along fault edges could explain why mainshocks are rarely followed by further large earthquakes.

scholarly journals Application of energy dissipation and damping structure in the reinforcement of shear wall in concrete engineering

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 631-641
Author(s):  
Shujuan Yang
Keyword(s):  
Energy Dissipation ◽  
Design Process ◽  
Large Earthquake ◽  
Shear Wall ◽  
Original Method ◽  
Steel Technology ◽  
Dissipation Structure ◽  
Shear Damping ◽  
Better Than

AbstractIn view of the problem of large earthquake displacement in the use of the original concrete engineering shear wall reinforcement method, the energy dissipation and damping structure is used to design the energy dissipation and damping structure reinforcement method in the concrete engineering shear wall. According to the design process of the set method, the anti-vibration coefficient of the concrete shear wall is tested. The energy dissipation structure is used to construct a shear damping wall, and the damper is added to the original shear wall. The concrete shear wall is strengthened by sticking steel technology. So far, the design of shear wall reinforcement method based on the energy dissipation structure has been completed. Compared with the original method, the displacement distance of this method is lower than that of the original method. In conclusion, the effect of shear wall reinforcement method based on the energy dissipation structure is better than that of the original method.

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