Focused on the current situation,monitoring system,technical management regulation,process,system composition,and information publication of the earthquake information release,we summarized the construction and develo...Focused on the current situation,monitoring system,technical management regulation,process,system composition,and information publication of the earthquake information release,we summarized the construction and development of China’s earthquake information release system and expected its future.In general,China’s earthquake information release systems is able to publish auto-results with MS≥3.0 from 1 to 3 minutes,M_S≥6.0 in global from 2 to 30 minutes,and formal results with MS≥3.0 in China from 8 to 30 minutes,MS≥6.0 in global from 20 to 60 minutes.These earthquake information is released by various channels such as short message,website,microblog,mobile application,etc.展开更多
1 SURVEY OF GLOBAL SEISMICITY A total of 5 strong earthquakes with M S≥7.0 occurred in the first half of 2018(from January 1 to May 31,2018)throughout the world,according to CENC(China Earthquake Networks Center),in...1 SURVEY OF GLOBAL SEISMICITY A total of 5 strong earthquakes with M S≥7.0 occurred in the first half of 2018(from January 1 to May 31,2018)throughout the world,according to CENC(China Earthquake Networks Center),including one with M S≥8.0(M W7.9),which occurred on January 23,2018 in Alaska(Fig.1).The 2018 M S8.0 Alaska earthquake was located in the north of the Circum-Pacific Seismic Belt.The mainshock was slip type and the rupture was unilateral along the NW direction,with maximum intensityⅩ.Features of global seismicity of M S≥7.0 in the first half year of 2018 are as follows.1.1 The Global Seismicity Was Similar to 2017 But Weaker Than Previous Years One earthquake with M S≥8.0 occurred in the first half of 2018.The global seismic strength stayed nearly the same compared with the earthquake with M S≥8.0 in 2017(Fig.2(a)).There were 5 earthquakes with M≥7.0 occurring in the world in the first half of 2018.The seismic frequency was similar to 2017,which had 8 strong earthquakes with M S≥7.0,but was significantly lower than the annual average of 19 strong earthquakes(Fig.2(b)).展开更多
The Gutenberg-Richter law (G-R law) of the magnitude-frequency distribution of earthquakes has been an important base in seismology for a long time. However, the actual magnitude-frequency distribution usually deviate...The Gutenberg-Richter law (G-R law) of the magnitude-frequency distribution of earthquakes has been an important base in seismology for a long time. However, the actual magnitude-frequency distribution usually deviates from the G-R law. Based on the experimental results of three different rock samples, which contain macro-asperity, compressional en-echelon fault and model-Ⅲ shear fault, the correlative coefficient (r) was calculated by fitting the sequences of the acoustic emissions with the G-R law in every scanning time window. We investigated the changes of the correlative coefficient, which describes the actual deviation of magnitude-frequency distribution of earthquakes from the G-R law within the specific scanning time window. According to the results of the rock samples containing macro-asperity and compressional en-echelon fault respectively, the value decreases prior to the rock fracture, meaning that the deviation of magnitude-frequency distribution from the G-R law tends to be larger. The result of the model-Ⅲ shear fault didn’t show obvious decrease before the final rock fracture. Actually, the studies of some earthquakes also show deviation before the occurrence of moderate earthquakes. The results obtained in this paper will provide us with some useful clues for studying precursors before the occurrence of moderate earthquakes with the data of regional earthquake activities.展开更多
基金the Network Center Seismic Network Department daily operation and maintenance funding support(1950411001)
文摘Focused on the current situation,monitoring system,technical management regulation,process,system composition,and information publication of the earthquake information release,we summarized the construction and development of China’s earthquake information release system and expected its future.In general,China’s earthquake information release systems is able to publish auto-results with MS≥3.0 from 1 to 3 minutes,M_S≥6.0 in global from 2 to 30 minutes,and formal results with MS≥3.0 in China from 8 to 30 minutes,MS≥6.0 in global from 20 to 60 minutes.These earthquake information is released by various channels such as short message,website,microblog,mobile application,etc.
文摘1 SURVEY OF GLOBAL SEISMICITY A total of 5 strong earthquakes with M S≥7.0 occurred in the first half of 2018(from January 1 to May 31,2018)throughout the world,according to CENC(China Earthquake Networks Center),including one with M S≥8.0(M W7.9),which occurred on January 23,2018 in Alaska(Fig.1).The 2018 M S8.0 Alaska earthquake was located in the north of the Circum-Pacific Seismic Belt.The mainshock was slip type and the rupture was unilateral along the NW direction,with maximum intensityⅩ.Features of global seismicity of M S≥7.0 in the first half year of 2018 are as follows.1.1 The Global Seismicity Was Similar to 2017 But Weaker Than Previous Years One earthquake with M S≥8.0 occurred in the first half of 2018.The global seismic strength stayed nearly the same compared with the earthquake with M S≥8.0 in 2017(Fig.2(a)).There were 5 earthquakes with M≥7.0 occurring in the world in the first half of 2018.The seismic frequency was similar to 2017,which had 8 strong earthquakes with M S≥7.0,but was significantly lower than the annual average of 19 strong earthquakes(Fig.2(b)).
基金This research was sponsored by the Joint EarthquakeScience Foundation,China (A07007)
文摘The Gutenberg-Richter law (G-R law) of the magnitude-frequency distribution of earthquakes has been an important base in seismology for a long time. However, the actual magnitude-frequency distribution usually deviates from the G-R law. Based on the experimental results of three different rock samples, which contain macro-asperity, compressional en-echelon fault and model-Ⅲ shear fault, the correlative coefficient (r) was calculated by fitting the sequences of the acoustic emissions with the G-R law in every scanning time window. We investigated the changes of the correlative coefficient, which describes the actual deviation of magnitude-frequency distribution of earthquakes from the G-R law within the specific scanning time window. According to the results of the rock samples containing macro-asperity and compressional en-echelon fault respectively, the value decreases prior to the rock fracture, meaning that the deviation of magnitude-frequency distribution from the G-R law tends to be larger. The result of the model-Ⅲ shear fault didn’t show obvious decrease before the final rock fracture. Actually, the studies of some earthquakes also show deviation before the occurrence of moderate earthquakes. The results obtained in this paper will provide us with some useful clues for studying precursors before the occurrence of moderate earthquakes with the data of regional earthquake activities.
