Seismic risk evaluation(SRE) in early stages(e.g., project planning and preliminary design)for a mountain tunnel located in seismic areas has the same importance as that in final stages(e.g.,performance-based design, ...Seismic risk evaluation(SRE) in early stages(e.g., project planning and preliminary design)for a mountain tunnel located in seismic areas has the same importance as that in final stages(e.g.,performance-based design, structural analysis, and optimization). SRE for planning mountain tunnels bridges the gap between the planning on the macro level and the design/analysis on the micro level regarding the risk management of infrastructural systems. A transition from subjective or qualitative description to objective or quantitative quantification of seismic risk is aimed to improve the seismic behavior of the mountain tunnel and thus reduce the associated seismic risk. A new method of systematic SRE for the planning mountain tunnel was presented herein. The method employs extension theory(ET)and an ET-based improved analytical hierarchy process. Additionally, a new risk-classification criterion is proposed to classify and quantify the seismic risk for a planning mountain tunnel. This SRE method is applied to a mountain tunnel in southwest China, using the extension model based on matter element theory and dependent function operation.The reasonability and flexibility of the SRE method for application to the mountain tunnel are illustrated.According to different seismic risk levels and classification criteria, methods and measures for improving the seismic design are proposed, which can reduce the seismic risk and provide a frame of reference for elaborate seismic design.展开更多
The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the wo...The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the world.A research program has been carried out by the State Seismological Bureau of China.Based on the size of the reservoir and the lithology,geological structure,permeability,stress state,and previous seismicity in the region,the potential risk of reservoir-induced seismicity has been estimated.The results suggest that,after impoundment in the reservoir area,the possibility of induced seismicity cannot be completely ruled out.The areas with potential risk may be in some gorges composed of karstified carbonate and plutonic granite around the dam site.However,the magnitude is expected to be limited owing to the small dimension of the induced seismogenic faults.展开更多
The reason for the failure to forecast the Wenchuan M_S8.0 earthquake is under study, based on the systematically collection of the seismicity anomalies and their analysis results from annual earthquake tendency forec...The reason for the failure to forecast the Wenchuan M_S8.0 earthquake is under study, based on the systematically collection of the seismicity anomalies and their analysis results from annual earthquake tendency forecasts between the 2001 Western Kunlun Mountains Pass M_S8.1 earthquake and the 2008 Wenchuan M_S8.0 earthquake. The results show that the earthquake tendency estimation of Chinese Mainland is for strong earthquakes to occur in the active stage, and that there is still potential for the occurrence of a M_S8.0 large earthquake in Chinese Mainland after the 2001 Western Kunlun Mountains Pass earthquake. However the phenomena that many large earthquakes occurred around Chinese Mainland, and the 6-year long quietude of M_S7.0 earthquake and an obvious quietude of M_S5.0 and M_S6.0 earthquakes during 2002～2007 led to the distinctly lower forecast estimation of earthquake tendency in Chinese Mainland after 2006. The middle part in the north-south seismic belt has been designated a seismic risk area of strong earthquake in recent years, but, the estimation of the risk degree in Southwestern China is insufficient after the Ning’er M_S6.4 earthquake in Yunnan in 2007. There are no records of earthquakes with M_S≥7.0 in the Longmenshan fault, which is one of reasons that this fault was not considered a seismic risk area of strong earthquakes in recent years.展开更多
Based on faults surveying and research data in the Tianjin offshore areas,through studying tectonic structure,Quaternary activity,deep structure,stress and strain fields and seismicity in the Tianjin offshore areas,th...Based on faults surveying and research data in the Tianjin offshore areas,through studying tectonic structure,Quaternary activity,deep structure,stress and strain fields and seismicity in the Tianjin offshore areas,the activity and tectonic features of the faults are determined synthetically.Using seismo-geological data,and the historical and modern seismicity data,the frequency-magnitude relationship model normalized by 500a is established and based on the relationship between the upper limit of maximum magnitude M u and a t/b,the maximum magnitudes of the sea section of the Haihe river fault and the Haiyi fault are calculated.Then Poisson probability model is adopted and the quantitative parameters,such as the maximum magnitude,occurrence probability,recurrence cycle of the faults in the south Tianjin offshore areas in the coming 50～200a,are calculated.展开更多
This paper introduces a new method to estimate the seismic hazard on engineering site.The method is mainly based on intensity data of historical earthquakes.The obvious feature of the method is to use some ideas of se...This paper introduces a new method to estimate the seismic hazard on engineering site.The method is mainly based on intensity data of historical earthquakes.The obvious feature of the method is to use some ideas of seismic hazard analysis and considering regional seismicity tendency.The authors depict the comprehensive method to estimate the related parameters and predict the seismic hazards for 14 sites as practical examples.Some problems are also discussed.Compared with seismic hazard analysis,this method has certain advantages,such as simpler computation,lower uncertainty and smaller sensitivity factor.Moreover total hazard P(I≥i)of a site can be examined with real historic data.The result given by the method in this paper can be more stable than that given by seismic hazard analysis nowadays.展开更多
According to the results of estimation of the maximum potential earthquake in the project of "The Active Fault Detection and Seismic Risk Evaluation( Phase II) of Zhengzhou City",the near east-west trending ...According to the results of estimation of the maximum potential earthquake in the project of "The Active Fault Detection and Seismic Risk Evaluation( Phase II) of Zhengzhou City",the near east-west trending Laoyachen fault and Shangjie fault are developed in the urban area.The Laoyachen fault was not active in the Quaternary,but the Shangjie fault may have the potential of generating M5.0~5.5 earthquakes.In order to get the probability of occurrence of maximum potential earthquakes,we delineate the statistical areas and the potential source areas and calculate the seismicity parameters and the space distribution functions.Our study shows that the probability of occurrence of an earthquake with M≥5.0 on the faults in Zhengzhou city is 6% in the next 50 years and 11% in the next 100years.展开更多
Based on geometric structure,active strength,and maximum seismic rupture length along the fault in the late Quaternary or Holocene,this paper presents the segmentation of main active faults in Sichuan Province and use...Based on geometric structure,active strength,and maximum seismic rupture length along the fault in the late Quaternary or Holocene,this paper presents the segmentation of main active faults in Sichuan Province and uses the recurrence probability model to predict the recurrence probabilities of strong earthquakes along each segment during next 30 years.The results indicate that earthquakes with M=7.0 or greater may happen along Qiajiao segment,Qianning segment,and Selaha segment of Xianshuihe fault zone,the segment from Xichang to Mianning and Yejidong segment of Anninghe fault zone; earthquakes with M=6.0 or greater may happen along the segment from Maowen to Caopuo of Longmenshan fault zone and Xiaoyanjing segment of Anninghe fault zone.展开更多
Analysis of seismic data and seismicity characteristics in China, we gave a method to deal with seismic patterns by calculating density at grid nodes. Number of earthquakes and epicenter distribution are considered co...Analysis of seismic data and seismicity characteristics in China, we gave a method to deal with seismic patterns by calculating density at grid nodes. Number of earthquakes and epicenter distribution are considered comprehen-sively in this method. Effect of datum accuracy is stressed on parameter confirmation. Seismic patterns from this method are stable and can reflect seismic characteristics reliably. These seismic patterns are the base of quantita-tive analysis of seismicity. It can be applied in seismic tendency analysis and medium-long term earthquake pre-diction, earthquake countermeasure and risk mitigation.展开更多
基金financially supported by the National Key Research and Development Program of China (2016YFB1200401)the Western Construction Project of the Ministry of Transport (Grant No. 2015318J29040)
文摘Seismic risk evaluation(SRE) in early stages(e.g., project planning and preliminary design)for a mountain tunnel located in seismic areas has the same importance as that in final stages(e.g.,performance-based design, structural analysis, and optimization). SRE for planning mountain tunnels bridges the gap between the planning on the macro level and the design/analysis on the micro level regarding the risk management of infrastructural systems. A transition from subjective or qualitative description to objective or quantitative quantification of seismic risk is aimed to improve the seismic behavior of the mountain tunnel and thus reduce the associated seismic risk. A new method of systematic SRE for the planning mountain tunnel was presented herein. The method employs extension theory(ET)and an ET-based improved analytical hierarchy process. Additionally, a new risk-classification criterion is proposed to classify and quantify the seismic risk for a planning mountain tunnel. This SRE method is applied to a mountain tunnel in southwest China, using the extension model based on matter element theory and dependent function operation.The reasonability and flexibility of the SRE method for application to the mountain tunnel are illustrated.According to different seismic risk levels and classification criteria, methods and measures for improving the seismic design are proposed, which can reduce the seismic risk and provide a frame of reference for elaborate seismic design.
文摘The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the world.A research program has been carried out by the State Seismological Bureau of China.Based on the size of the reservoir and the lithology,geological structure,permeability,stress state,and previous seismicity in the region,the potential risk of reservoir-induced seismicity has been estimated.The results suggest that,after impoundment in the reservoir area,the possibility of induced seismicity cannot be completely ruled out.The areas with potential risk may be in some gorges composed of karstified carbonate and plutonic granite around the dam site.However,the magnitude is expected to be limited owing to the small dimension of the induced seismogenic faults.
基金sponsored by the Key Project of Chinese National Programs for Fundamental Research and Development (973 program) (2004CB418406)the State Science and Technology Program of Tackle Key Problem(2006BAC01B02-01-04),China
文摘The reason for the failure to forecast the Wenchuan M_S8.0 earthquake is under study, based on the systematically collection of the seismicity anomalies and their analysis results from annual earthquake tendency forecasts between the 2001 Western Kunlun Mountains Pass M_S8.1 earthquake and the 2008 Wenchuan M_S8.0 earthquake. The results show that the earthquake tendency estimation of Chinese Mainland is for strong earthquakes to occur in the active stage, and that there is still potential for the occurrence of a M_S8.0 large earthquake in Chinese Mainland after the 2001 Western Kunlun Mountains Pass earthquake. However the phenomena that many large earthquakes occurred around Chinese Mainland, and the 6-year long quietude of M_S7.0 earthquake and an obvious quietude of M_S5.0 and M_S6.0 earthquakes during 2002～2007 led to the distinctly lower forecast estimation of earthquake tendency in Chinese Mainland after 2006. The middle part in the north-south seismic belt has been designated a seismic risk area of strong earthquake in recent years, but, the estimation of the risk degree in Southwestern China is insufficient after the Ning’er M_S6.4 earthquake in Yunnan in 2007. There are no records of earthquakes with M_S≥7.0 in the Longmenshan fault, which is one of reasons that this fault was not considered a seismic risk area of strong earthquakes in recent years.
基金funded by earthquake security infrastructure of Tianjin 11th "Five-year Plan" (Tianjin Development and Reforming Office[2009]-1230),the Spark Program of Earthquake Sciences(Grant No.XH13002)
文摘Based on faults surveying and research data in the Tianjin offshore areas,through studying tectonic structure,Quaternary activity,deep structure,stress and strain fields and seismicity in the Tianjin offshore areas,the activity and tectonic features of the faults are determined synthetically.Using seismo-geological data,and the historical and modern seismicity data,the frequency-magnitude relationship model normalized by 500a is established and based on the relationship between the upper limit of maximum magnitude M u and a t/b,the maximum magnitudes of the sea section of the Haihe river fault and the Haiyi fault are calculated.Then Poisson probability model is adopted and the quantitative parameters,such as the maximum magnitude,occurrence probability,recurrence cycle of the faults in the south Tianjin offshore areas in the coming 50～200a,are calculated.
文摘This paper introduces a new method to estimate the seismic hazard on engineering site.The method is mainly based on intensity data of historical earthquakes.The obvious feature of the method is to use some ideas of seismic hazard analysis and considering regional seismicity tendency.The authors depict the comprehensive method to estimate the related parameters and predict the seismic hazards for 14 sites as practical examples.Some problems are also discussed.Compared with seismic hazard analysis,this method has certain advantages,such as simpler computation,lower uncertainty and smaller sensitivity factor.Moreover total hazard P(I≥i)of a site can be examined with real historic data.The result given by the method in this paper can be more stable than that given by seismic hazard analysis nowadays.
基金sponsored by the Seismic Risk Assessment of Active Fault in Key Monitoring Prevention Area of China
文摘According to the results of estimation of the maximum potential earthquake in the project of "The Active Fault Detection and Seismic Risk Evaluation( Phase II) of Zhengzhou City",the near east-west trending Laoyachen fault and Shangjie fault are developed in the urban area.The Laoyachen fault was not active in the Quaternary,but the Shangjie fault may have the potential of generating M5.0~5.5 earthquakes.In order to get the probability of occurrence of maximum potential earthquakes,we delineate the statistical areas and the potential source areas and calculate the seismicity parameters and the space distribution functions.Our study shows that the probability of occurrence of an earthquake with M≥5.0 on the faults in Zhengzhou city is 6% in the next 50 years and 11% in the next 100years.
基金This study was granted by No.85-05-03-04 subject of the State Seismological Bureau,China.
文摘Based on geometric structure,active strength,and maximum seismic rupture length along the fault in the late Quaternary or Holocene,this paper presents the segmentation of main active faults in Sichuan Province and uses the recurrence probability model to predict the recurrence probabilities of strong earthquakes along each segment during next 30 years.The results indicate that earthquakes with M=7.0 or greater may happen along Qiajiao segment,Qianning segment,and Selaha segment of Xianshuihe fault zone,the segment from Xichang to Mianning and Yejidong segment of Anninghe fault zone; earthquakes with M=6.0 or greater may happen along the segment from Maowen to Caopuo of Longmenshan fault zone and Xiaoyanjing segment of Anninghe fault zone.
文摘Analysis of seismic data and seismicity characteristics in China, we gave a method to deal with seismic patterns by calculating density at grid nodes. Number of earthquakes and epicenter distribution are considered comprehen-sively in this method. Effect of datum accuracy is stressed on parameter confirmation. Seismic patterns from this method are stable and can reflect seismic characteristics reliably. These seismic patterns are the base of quantita-tive analysis of seismicity. It can be applied in seismic tendency analysis and medium-long term earthquake pre-diction, earthquake countermeasure and risk mitigation.
