5:15 PM - 7:15 PM
[SSS11-P21] Exploring the Impact of Fault Geometry on Earthquake Risk Assessment Based on Physical Simulation Methods
Keywords:Fault Geometry, Earthquake Risk Assessment, Deterministic Earthquake Scenario, Physical Simulation Methods, Stepover Fault, Zhujiangkou Fault
The deterministic earthquake models play a crucial role in enhancing the accuracy of seismic risk assessments. Unlike kinematic models, dynamic rupture simulations provide a more consistent approach, illustrating earthquakes' initiation, propagation, and termination while effectively predicting seismic time histories and spatial distributions. However, achieving successful dynamic rupture simulations requires careful selection of initial conditions, such as stress state, fault friction, and geometry. Despite these advances, the effect of fault geometry on seismic risk and damage, particularly in large metropolitan areas, remains inadequately explored.
This study focuses on the Zhujiangkou Fault (ZF) in southern China by developing three-dimensional, nonplanar dynamic rupture models with varying geometric complexities. These models were used to perform physics-based deterministic seismic scenario simulations and comprehensive seismic hazard and loss assessments. The simulations accounted for stress conditions, fault friction, velocity media, and topography, incorporating a variety of socio-economic factors such as population and asset exposure, inconsistencies in vulnerability models over time and space, and the influence of nighttime lighting. The uncertainty of the numerical simulations was also evaluated using empirical ground motion prediction equations (GMPEs).
The results indicate that the stepover zone of the fault impedes the propagation of seismic waves at the surface. However, the fault strike significantly impacts seismic hazard and loss assessments more than the stepover zone. Additionally, the uncertainty associated with the overall risk of economic losses (both in scale and probability) is considerably lower than the uncertainty surrounding population loss. As a key factor influencing seismic hazard distribution, fault geometry is crucial in population loss risk assessment. Further, an analysis of friction conditions for continuous fault rupture and stepover fault cascading rupture revealed that none of the scenarios resulted in these phenomena.
In conclusion, while the likelihood of an earthquake with a magnitude of 7 or greater on the ZF is relatively low, the potential seismic hazards and associated losses remain substantial and cannot be disregarded. The seismic risk and potential losses in the eastern coastal areas of the Guangdong-Hong Kong-Macao Greater Bay Area (GGBA) are significantly higher compared to the western regions, with the highest risk concentrated in Guangzhou, followed by Dongguan, Shenzhen, and the coastal areas of Hong Kong. The findings of this study are valuable for guiding future seismic risk mitigation and earthquake preparedness planning for the ZF in the GGBA.
This study focuses on the Zhujiangkou Fault (ZF) in southern China by developing three-dimensional, nonplanar dynamic rupture models with varying geometric complexities. These models were used to perform physics-based deterministic seismic scenario simulations and comprehensive seismic hazard and loss assessments. The simulations accounted for stress conditions, fault friction, velocity media, and topography, incorporating a variety of socio-economic factors such as population and asset exposure, inconsistencies in vulnerability models over time and space, and the influence of nighttime lighting. The uncertainty of the numerical simulations was also evaluated using empirical ground motion prediction equations (GMPEs).
The results indicate that the stepover zone of the fault impedes the propagation of seismic waves at the surface. However, the fault strike significantly impacts seismic hazard and loss assessments more than the stepover zone. Additionally, the uncertainty associated with the overall risk of economic losses (both in scale and probability) is considerably lower than the uncertainty surrounding population loss. As a key factor influencing seismic hazard distribution, fault geometry is crucial in population loss risk assessment. Further, an analysis of friction conditions for continuous fault rupture and stepover fault cascading rupture revealed that none of the scenarios resulted in these phenomena.
In conclusion, while the likelihood of an earthquake with a magnitude of 7 or greater on the ZF is relatively low, the potential seismic hazards and associated losses remain substantial and cannot be disregarded. The seismic risk and potential losses in the eastern coastal areas of the Guangdong-Hong Kong-Macao Greater Bay Area (GGBA) are significantly higher compared to the western regions, with the highest risk concentrated in Guangzhou, followed by Dongguan, Shenzhen, and the coastal areas of Hong Kong. The findings of this study are valuable for guiding future seismic risk mitigation and earthquake preparedness planning for the ZF in the GGBA.