In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred...In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred within or near the Chuandian rhombic block have strike-slip mechanism. The orientations of maximum compressive stresses obtained from source mechanism are changed from NNW-SSN to NS in the areas from north to south of the block, and tensile stresses are mainly in ENE-WSW or NE-SE. In the eastern Tibetan Plateau, the orientations of maximum compressive stress radiate toward outside from the plateau, and the tensile stress orientations mostly parallel to arc structures. Near 28N the orientations of both maximum compressive stress and tensile stress changed greatly, and the boundary seems to correspond to the southwestern extended line of Longmenshan fault. Outside of the Chuandian rhombic block, the orientations of P and T axes are some different from those within the block. The comparison shows that the source mechanism of small-moderate events presented in the paper is consistence with that of moderate-strong earthquakes determined by Harvard University, which means the source mechanism of small-moderate events can be used to study the tectonic stress field in this region.展开更多
In this paper,characteristics of spatial and temporal variation of linear fitting goodness before some moderately strong earthquakes(Ms≥5.0)in the eastern part of China(east of longitude 180)are studied according to ...In this paper,characteristics of spatial and temporal variation of linear fitting goodness before some moderately strong earthquakes(Ms≥5.0)in the eastern part of China(east of longitude 180)are studied according to the famous Gutenberg-Richter’s relation expressed as lgN=a-bM,by using the moderate and small events that occurred in and around the source area.The results show that the linear goodness of fitting varies abnormally prior to these moderately strong earthquakes.In the early stage of the earthquake preparatory process,distribution of the energy released through small events in and around the source area is isostatic and the fitting goodness approximates 1,while the distribution of the energy turns to be isostatic before moderately strong earthquakes,leading to the obvious decrease of the linear goodness of fitting.This phenomenon could be a medium term anomaly and a medium term criterion for moderately strong earthquake prediction.展开更多
The moment tensor solutions of 51 small to moderate earthquakes occurred in the Capital Region in the year of 2004 are obtained by inverting the broadband waveform data. Accordingly, other source parameters, such as s...The moment tensor solutions of 51 small to moderate earthquakes occurred in the Capital Region in the year of 2004 are obtained by inverting the broadband waveform data. Accordingly, other source parameters, such as scalar seismic moments, moment magnitudes, double-couple （DC） components and compensated-linear-vector-dipole （CLVD） components, are determined as well as fault parameters and stress-axis parameters. The inverted results are evaluated by groups of numerical tests.展开更多
Based on digital seismic waveform data from Inner Mongolia Digital Seismic Network,the source spectrum parameters of 182 small and moderate earthquakes from January,2009to September,2016 are derived,and the seismic mo...Based on digital seismic waveform data from Inner Mongolia Digital Seismic Network,the source spectrum parameters of 182 small and moderate earthquakes from January,2009to September,2016 are derived,and the seismic momentmoment magnitude MW of the earthquakes are calculated.Theand the relationship between stress drop and magnitude are obtained using the linear regression method.It is clear that incorporating the moment magnitude into the seismic quick report catalog and the official earthquake catalog can enrich earthquake observation report content,thus providing better service for earthquake emergency and earthquake scientific research.展开更多
Illustration All the data in this catalog are chosen from the Preliminary Seismological Report of ChineseSeismic Stations (abbreviated to Monthly Report).The catalog includes the events of M≥4.7 inand near China and ...Illustration All the data in this catalog are chosen from the Preliminary Seismological Report of ChineseSeismic Stations (abbreviated to Monthly Report).The catalog includes the events of M≥4.7 inand near China and M≥6 all over the world.The Monthly Report is monthly complied by theNinth Section of Institute of Geophysics,CSB.展开更多
The uncertainty of potential seismic regions for moderately strong earthquakes has a great effect on the results of seismic hazard analysis in weak seismicity regions,so it is the basement of seismic zoning and seismi...The uncertainty of potential seismic regions for moderately strong earthquakes has a great effect on the results of seismic hazard analysis in weak seismicity regions,so it is the basement of seismic zoning and seismic hazard assessment for engineering sites by correctly dividing the potential seismic regions for moderately strong earthquakes.By taking Northeast and North China as examples,the authors compiled and systematically analyzed a large amount of basic data and then suggest the principles and methods of potential seismic regions for moderately strong earthquakes based on a great number of case studies.The practical division of potential seismic regions in the Changchun and Jilin areas shows that these principles and methods show better suitability.Moreover,the authors also discuss in this paper the progress obtained and put forward some problems that should be solved in the future.展开更多
This research aims at proposing to the technical manager of a hospital, a method for assessing the vulnerability of the hospital system in the case of a moderate earthquake. A primary case study on a hospital centre h...This research aims at proposing to the technical manager of a hospital, a method for assessing the vulnerability of the hospital system in the case of a moderate earthquake. A primary case study on a hospital centre has allowed us to define the methodological basis. Also, it concludes to the need for a systematic method due to the complexity of hospital system and the specific knowledge. This ＂screening method＂ exits but it is applicable to the context of a major earthquake, where the main objective is to save life, while ours is to guarantee the continuity of hospital services. Other aims are to adapt this method in order to introduce the concept of a moderate earthquake, to take into account the environmental interactions of the hospital system and to improve the knowledge base. Subsequently, a software tool has to be developed to facilitate the implementation for the technical manager.展开更多
基金The National Key Basic Research Program under the Project "Mechanism and Prediction of Continental Strong Earthquake"(G1998040700) and Joint Seismological Science Foundation of China (100108).
文摘In the paper, source mechanisms of 33 small-moderate earthquakes occurred in Yunnan are determined by modeling of regional waveforms from Yunnan digital seismic network. The result shows that most earthquakes occurred within or near the Chuandian rhombic block have strike-slip mechanism. The orientations of maximum compressive stresses obtained from source mechanism are changed from NNW-SSN to NS in the areas from north to south of the block, and tensile stresses are mainly in ENE-WSW or NE-SE. In the eastern Tibetan Plateau, the orientations of maximum compressive stress radiate toward outside from the plateau, and the tensile stress orientations mostly parallel to arc structures. Near 28N the orientations of both maximum compressive stress and tensile stress changed greatly, and the boundary seems to correspond to the southwestern extended line of Longmenshan fault. Outside of the Chuandian rhombic block, the orientations of P and T axes are some different from those within the block. The comparison shows that the source mechanism of small-moderate events presented in the paper is consistence with that of moderate-strong earthquakes determined by Harvard University, which means the source mechanism of small-moderate events can be used to study the tectonic stress field in this region.
文摘In this paper,characteristics of spatial and temporal variation of linear fitting goodness before some moderately strong earthquakes(Ms≥5.0)in the eastern part of China(east of longitude 180)are studied according to the famous Gutenberg-Richter’s relation expressed as lgN=a-bM,by using the moderate and small events that occurred in and around the source area.The results show that the linear goodness of fitting varies abnormally prior to these moderately strong earthquakes.In the early stage of the earthquake preparatory process,distribution of the energy released through small events in and around the source area is isostatic and the fitting goodness approximates 1,while the distribution of the energy turns to be isostatic before moderately strong earthquakes,leading to the obvious decrease of the linear goodness of fitting.This phenomenon could be a medium term anomaly and a medium term criterion for moderately strong earthquake prediction.
基金The International 973 Programs (2001CB711005 and 2004DFA06000) the Special Program of China Earthquake Administration (2004BA601B)
文摘The moment tensor solutions of 51 small to moderate earthquakes occurred in the Capital Region in the year of 2004 are obtained by inverting the broadband waveform data. Accordingly, other source parameters, such as scalar seismic moments, moment magnitudes, double-couple （DC） components and compensated-linear-vector-dipole （CLVD） components, are determined as well as fault parameters and stress-axis parameters. The inverted results are evaluated by groups of numerical tests.
基金sponsored by the Major Science and Technology Projects in Inner Mongolia Autonomous Region “Research,Development,Popularization and Demonstration of Earthquake Prediction and Early Warning Technology in Key Areas”
文摘Based on digital seismic waveform data from Inner Mongolia Digital Seismic Network,the source spectrum parameters of 182 small and moderate earthquakes from January,2009to September,2016 are derived,and the seismic momentmoment magnitude MW of the earthquakes are calculated.Theand the relationship between stress drop and magnitude are obtained using the linear regression method.It is clear that incorporating the moment magnitude into the seismic quick report catalog and the official earthquake catalog can enrich earthquake observation report content,thus providing better service for earthquake emergency and earthquake scientific research.
文摘Illustration All the data in this catalog are chosen from the Preliminary Seismological Report of ChineseSeismic Stations (abbreviated to Monthly Report).The catalog includes the events of M≥4.7 inand near China and M≥6 all over the world.The Monthly Report is monthly complied by theNinth Section of Institute of Geophysics,CSB.
基金This project was sponsored by the Joint Earthquake Science Foundation (91013), China, contribution No. 96A0007, Institute of Geophysics, SSB, China
文摘The uncertainty of potential seismic regions for moderately strong earthquakes has a great effect on the results of seismic hazard analysis in weak seismicity regions,so it is the basement of seismic zoning and seismic hazard assessment for engineering sites by correctly dividing the potential seismic regions for moderately strong earthquakes.By taking Northeast and North China as examples,the authors compiled and systematically analyzed a large amount of basic data and then suggest the principles and methods of potential seismic regions for moderately strong earthquakes based on a great number of case studies.The practical division of potential seismic regions in the Changchun and Jilin areas shows that these principles and methods show better suitability.Moreover,the authors also discuss in this paper the progress obtained and put forward some problems that should be solved in the future.
文摘This research aims at proposing to the technical manager of a hospital, a method for assessing the vulnerability of the hospital system in the case of a moderate earthquake. A primary case study on a hospital centre has allowed us to define the methodological basis. Also, it concludes to the need for a systematic method due to the complexity of hospital system and the specific knowledge. This ＂screening method＂ exits but it is applicable to the context of a major earthquake, where the main objective is to save life, while ours is to guarantee the continuity of hospital services. Other aims are to adapt this method in order to introduce the concept of a moderate earthquake, to take into account the environmental interactions of the hospital system and to improve the knowledge base. Subsequently, a software tool has to be developed to facilitate the implementation for the technical manager.
