目的探讨四种非静脉曲张性上消化道出血的危险性评分系统(Rockall再出血危险积分、Cedars-Sinai Medical Center预后指数、Blatchford入院危险性计分、The Baylor出血积分)对于已确定的非静脉曲张性上消化道出血的病人中再出血情况的预...目的探讨四种非静脉曲张性上消化道出血的危险性评分系统(Rockall再出血危险积分、Cedars-Sinai Medical Center预后指数、Blatchford入院危险性计分、The Baylor出血积分)对于已确定的非静脉曲张性上消化道出血的病人中再出血情况的预测能力。方法选取2002年-2007年消化内科收治的消化道出血病人753例,以四种危险性评分系统分别评分后,行卡方拟和优度检验检测数据分布的合理性,后计算受试者工作特性曲线(ROC曲线)下面积。结果四种评分系统的ROC曲线下面积分别为:Rockall再出血危险积分0.681(P<0.01,95%CI:0.638-0.723),Cedars-Sinai Medical Center预后指数0.685(P<0.01,95%CI:0.639-0.731),Blatchford入院危险性计分0.886(P<0.01,95%CI:0.857-0.916),The Baylor出血积分0.737(P<0.01,95%CI:0.95-0.779)。结论①四种评分系统均对再出血有预测性。②Blatchford入院危险性计分更适用于门诊及急诊。展开更多
Assessment of debris flow hazards is important for developing measures to mitigate the loss of life and property and to minimize environmental damage. Two modified uncertainty models, Set Pair Analysis （SPA） and mod...Assessment of debris flow hazards is important for developing measures to mitigate the loss of life and property and to minimize environmental damage. Two modified uncertainty models, Set Pair Analysis （SPA） and modified Set Pair Analysis （mSPA）, were suggested to assess the regional debris flow hazard. A ease study was conducted in seven towns of the Beichuan county, Sichuan Province, China, to test and compare the application of these two models in debris flow hazard assessment. The results showed that mSPA only can fit for value-variables, but not for non value-variable assessment indexes, Furthermore, as for a given assessment index xi, mSPA only considers two cases, namely, when grade value increases with xi and when grade value decreases with xi. Thus, mSPA can not be used for debris flow hazard assessment but SPA is credible for the assessment because there are no limitations when using SPA model to assess the debris flow hazard. Therefore, in this study SPA is proposed for assessing debris flow hazard.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 H） of Zhengzhou City＂, the near east-west trending Laoyac...According to the results of estimation of the maximum potential earthquake in the project of ＂The Active Fault Detection and Seismic Risk Evaluation （Phase H） 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 100 years.展开更多
A new probabilistic seismic hazard analysis was performed for the city of Bridgetown, Barbados, West Indies. Hazard computations have been performed using the standard Cornell-McGuire approach based on the definition ...A new probabilistic seismic hazard analysis was performed for the city of Bridgetown, Barbados, West Indies. Hazard computations have been performed using the standard Cornell-McGuire approach based on the definition of appropriate seismogenic sources and expected maximum magnitudes, the authors take into consideration the possibility of large subduction interface earthquakes of magnitude 8.0-9.0 beneath the Barbados accretionary prism via application of a characteristic model and slip rates. The analysis has been conducted using a standard logic-tree approach. Uniform hazard spectra have been calculated for the 5% of critical damping and the horizontal component of ground motion for rock site conditions setting 5 return periods （95, 475, 975, 2,475 and 4,975 years） and spectral accelerations for 34 structural periods ranging from 0 to 3 s. The disaggregation results suggest that the magnitude-distance pair that dominates the hazard yields M 7.4 and 8.6 and a distance of 42.5 km in the Interface Subduction Zone beneath Barbados for the 475 and 975 years RP （return period）, respectively. An event with an M 8.0 at a distance of 107.5 km in the Intraplate Subduction Zone is the second scenario that dominates the hazard for both 475 and 975 years RP.展开更多
A probabilistic seismic hazard analysis was performed to generate seismic hazard maps for Jamaica. The analysis was then conducted using a standard logic-tree approach that allowed systematically taking into account t...A probabilistic seismic hazard analysis was performed to generate seismic hazard maps for Jamaica. The analysis was then conducted using a standard logic-tree approach that allowed systematically taking into account the model-based （i.e., epistemic） uncertainty and its influence on the computed ground motion parameters. Hazard computations have been performed using a grid of sites with a space of 0.05 degrees. Two different computation methodologies have been adopted： the standard approach based on the definition of appropriate seismogenic sources and the zone-free approach, which overcomes the ambiguities related with the definition of the seismic sources solely reflecting the characteristics of the earthquake catalogue. A comprehensive and updated earthquake catalogue for Jamaica has been compiled for the years 1551-2010 and new empirical relationships amongst magnitudes Mze-Ms and Mw-mb have been developed for the region. Uniform hazard spectra and their uncertainty have been calculated for the horizontal component of ground motion for rock site conditions and five return periods （95, 475, 975, 2,475 and 4,975 years） and spectral accelerations for 34 structural periods ranging from 0 to 3 s, and 5% of critical damping. The spectral accelerations have been calculated to allow the definition of seismic hazard in Jamaica according to the International Building Code 2012. The disaggregation analysis for Kingston Metropolitan Area suggests that the magnitude-distance pair that contributes most to the hazard corresponds to events with M 7.8 and M 7.0 in the Enriquillo Plantain Garden Fault and the Jamaican Faults at a distance of 28 km and 18 km for short and long period structures respectively corresponding to 2,475 years return period. However, for long period structures, a substantial contribution is found for a M 8.2 at a distance of 198 km in the Oriente Fault Zone.展开更多
The earthqnake emergency material preparation demand analysis can provide the scientific basis for all levels of governments to conduct reasonable and unified configuration of the emergency preparation resources, in o...The earthqnake emergency material preparation demand analysis can provide the scientific basis for all levels of governments to conduct reasonable and unified configuration of the emergency preparation resources, in order to further optimize the earthquake emergency ability construction to provide reference. This paper takes Datong City of Shanxi Province as an example, using the earthquake risk evaluation method, adopting the deterministic method and probabilistic method to conduct earthquake danger analysis, combined with the earthquake emergency rescue case and the previous scholars＇ research achievements, in order to study and analyze the earthquake emergency material preparation demand in different earthquake dangers.展开更多
The Lower Yangtze River-South Yellow Sea Seismic Zone,located at the southeast of the Northern China Seismic Zone, characterized by moderate-strong earthquakes, is an intensive earthquake zone,which is controlled by a...The Lower Yangtze River-South Yellow Sea Seismic Zone,located at the southeast of the Northern China Seismic Zone, characterized by moderate-strong earthquakes, is an intensive earthquake zone,which is controlled by a series of faults within the Lower Yangtze River-South Yellow Sea Seismic Zone. This article counts and calculates the bvalue,V 4 and energy density value of medium-small earthquakes by taking full advantage of the latest data from regional seismic stations,reviews data of historical earthquakes and seismic structure,and discusses the relationship between spatial distribution of the b-value, historical strong earthquakes and spatial distribution of energy density of medium-small earthquakes,and further investigates the seismic activity of the Lower Yangtze River- South Yellow Sea Seismic Zone. This article obtains seismic activity parameters of the Lower Yangtze River-South Yellow Sea Seismic Zone as calculation parameters for probabilistic seismic hazard analysis,and discusses the trend of this seismic zone in the next one hundred years and deduces the potential seismic hazard region within this seismic zone,which provides references and methods for long-term prediction on seismic activity. The research results are significant to seismic zoning, seismic safety evaluation of engineering sites and long-term prediction of seismic activity.展开更多
文摘目的探讨四种非静脉曲张性上消化道出血的危险性评分系统(Rockall再出血危险积分、Cedars-Sinai Medical Center预后指数、Blatchford入院危险性计分、The Baylor出血积分)对于已确定的非静脉曲张性上消化道出血的病人中再出血情况的预测能力。方法选取2002年-2007年消化内科收治的消化道出血病人753例,以四种危险性评分系统分别评分后,行卡方拟和优度检验检测数据分布的合理性,后计算受试者工作特性曲线(ROC曲线)下面积。结果四种评分系统的ROC曲线下面积分别为:Rockall再出血危险积分0.681(P<0.01,95%CI:0.638-0.723),Cedars-Sinai Medical Center预后指数0.685(P<0.01,95%CI:0.639-0.731),Blatchford入院危险性计分0.886(P<0.01,95%CI:0.857-0.916),The Baylor出血积分0.737(P<0.01,95%CI:0.95-0.779)。结论①四种评分系统均对再出血有预测性。②Blatchford入院危险性计分更适用于门诊及急诊。
基金supported by the National Natural Science Foundation of China (Grant Nos. 51279116)the New Teacher Fund of Ministry of Education of China (Grant No. 20120181120124)+1 种基金the Excellent Scholar Fund of Sichuan UniversityOpen Fund Program of State key Laboratory of Hydraulics and River Engineering, Sichuan University, China (Grant No. 0901)
文摘Assessment of debris flow hazards is important for developing measures to mitigate the loss of life and property and to minimize environmental damage. Two modified uncertainty models, Set Pair Analysis （SPA） and modified Set Pair Analysis （mSPA）, were suggested to assess the regional debris flow hazard. A ease study was conducted in seven towns of the Beichuan county, Sichuan Province, China, to test and compare the application of these two models in debris flow hazard assessment. The results showed that mSPA only can fit for value-variables, but not for non value-variable assessment indexes, Furthermore, as for a given assessment index xi, mSPA only considers two cases, namely, when grade value increases with xi and when grade value decreases with xi. Thus, mSPA can not be used for debris flow hazard assessment but SPA is credible for the assessment because there are no limitations when using SPA model to assess the debris flow hazard. Therefore, in this study SPA is proposed for assessing debris flow hazard.
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 H） 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 100 years.
文摘A new probabilistic seismic hazard analysis was performed for the city of Bridgetown, Barbados, West Indies. Hazard computations have been performed using the standard Cornell-McGuire approach based on the definition of appropriate seismogenic sources and expected maximum magnitudes, the authors take into consideration the possibility of large subduction interface earthquakes of magnitude 8.0-9.0 beneath the Barbados accretionary prism via application of a characteristic model and slip rates. The analysis has been conducted using a standard logic-tree approach. Uniform hazard spectra have been calculated for the 5% of critical damping and the horizontal component of ground motion for rock site conditions setting 5 return periods （95, 475, 975, 2,475 and 4,975 years） and spectral accelerations for 34 structural periods ranging from 0 to 3 s. The disaggregation results suggest that the magnitude-distance pair that dominates the hazard yields M 7.4 and 8.6 and a distance of 42.5 km in the Interface Subduction Zone beneath Barbados for the 475 and 975 years RP （return period）, respectively. An event with an M 8.0 at a distance of 107.5 km in the Intraplate Subduction Zone is the second scenario that dominates the hazard for both 475 and 975 years RP.
文摘A probabilistic seismic hazard analysis was performed to generate seismic hazard maps for Jamaica. The analysis was then conducted using a standard logic-tree approach that allowed systematically taking into account the model-based （i.e., epistemic） uncertainty and its influence on the computed ground motion parameters. Hazard computations have been performed using a grid of sites with a space of 0.05 degrees. Two different computation methodologies have been adopted： the standard approach based on the definition of appropriate seismogenic sources and the zone-free approach, which overcomes the ambiguities related with the definition of the seismic sources solely reflecting the characteristics of the earthquake catalogue. A comprehensive and updated earthquake catalogue for Jamaica has been compiled for the years 1551-2010 and new empirical relationships amongst magnitudes Mze-Ms and Mw-mb have been developed for the region. Uniform hazard spectra and their uncertainty have been calculated for the horizontal component of ground motion for rock site conditions and five return periods （95, 475, 975, 2,475 and 4,975 years） and spectral accelerations for 34 structural periods ranging from 0 to 3 s, and 5% of critical damping. The spectral accelerations have been calculated to allow the definition of seismic hazard in Jamaica according to the International Building Code 2012. The disaggregation analysis for Kingston Metropolitan Area suggests that the magnitude-distance pair that contributes most to the hazard corresponds to events with M 7.8 and M 7.0 in the Enriquillo Plantain Garden Fault and the Jamaican Faults at a distance of 28 km and 18 km for short and long period structures respectively corresponding to 2,475 years return period. However, for long period structures, a substantial contribution is found for a M 8.2 at a distance of 198 km in the Oriente Fault Zone.
文摘The earthqnake emergency material preparation demand analysis can provide the scientific basis for all levels of governments to conduct reasonable and unified configuration of the emergency preparation resources, in order to further optimize the earthquake emergency ability construction to provide reference. This paper takes Datong City of Shanxi Province as an example, using the earthquake risk evaluation method, adopting the deterministic method and probabilistic method to conduct earthquake danger analysis, combined with the earthquake emergency rescue case and the previous scholars＇ research achievements, in order to study and analyze the earthquake emergency material preparation demand in different earthquake dangers.
基金sponsored by Institute of Crustal Dynamics,China Earthquake Administration ( ZDJ2013-05 )the sub-project from the Ministry of National Science and Technique's project( 2011ZX05056-001-02)the Special Scientific Research Fund of Seismological Public Welfare Profession of China ( 200708055)
文摘The Lower Yangtze River-South Yellow Sea Seismic Zone,located at the southeast of the Northern China Seismic Zone, characterized by moderate-strong earthquakes, is an intensive earthquake zone,which is controlled by a series of faults within the Lower Yangtze River-South Yellow Sea Seismic Zone. This article counts and calculates the bvalue,V 4 and energy density value of medium-small earthquakes by taking full advantage of the latest data from regional seismic stations,reviews data of historical earthquakes and seismic structure,and discusses the relationship between spatial distribution of the b-value, historical strong earthquakes and spatial distribution of energy density of medium-small earthquakes,and further investigates the seismic activity of the Lower Yangtze River- South Yellow Sea Seismic Zone. This article obtains seismic activity parameters of the Lower Yangtze River-South Yellow Sea Seismic Zone as calculation parameters for probabilistic seismic hazard analysis,and discusses the trend of this seismic zone in the next one hundred years and deduces the potential seismic hazard region within this seismic zone,which provides references and methods for long-term prediction on seismic activity. The research results are significant to seismic zoning, seismic safety evaluation of engineering sites and long-term prediction of seismic activity.
