On the basis of the textual research on the historical earthquake data and the field investigation of Wudu earthquake occurred in 186 B.C., we suggest that the earthquake parameters drawn from the present earthquake c...On the basis of the textual research on the historical earthquake data and the field investigation of Wudu earthquake occurred in 186 B.C., we suggest that the earthquake parameters drawn from the present earthquake catalogs are not definite and amendments should be made. The heavily-damaged area of this earthquake should be located between Jugan township of Wudu County and Pingding township of Zhouqu County. Its epicenter should be in the vicinity of Lianghekou in Wudu County with a magnitude of about 7-7 1/4 and an intensity of about IX-X. The major axis direction of the heavily-damaged area should be in the WNW direction that is approximately consistent with the strike of the middle-east segment of Diebu-Bailongjiang active fault zone, and the origin time should match up to that of the latest paleoearthquake event [before （83±46） B.C.] obtained by the trench investigation. Certain seismic rupture evidences are still preserved on this fault segment. Therefore, we propose on the basis of comprehensive analysis that the causative structure of the M 7-7 1/4 Wudu earthquake in 186 B.C. should be in the middle-east segment of Diebu-Bailongjiang active fault zone.展开更多
Longxi earthquake was the only earthquake example, which ZHANG Heng＇s Seismometer had detected. Therefore this event attracted the attention of the academic circle and also served as crucial evidence to examine the r...Longxi earthquake was the only earthquake example, which ZHANG Heng＇s Seismometer had detected. Therefore this event attracted the attention of the academic circle and also served as crucial evidence to examine the rationality of the reconstructed model of the seismometer. But for a long time, owing to the fact that the Jincheng-Longxi earthquake on February 28, AD 138 was mistaken as the event went against the historical records, it was refuted by the researches of both in China and abroad. By making careful textual research of historical records, especially by analyzing the description of Longxi earthquake of Houhan Shu, by studying the historical background exposed by historical literatures at that time, ZHANG Heng＇s biography, his poems and place names of Han Dynasty, by comparing five earthquakes occurred in Qing Dynasty and their attenuation of seismic intensity, the conclusion can be drawn that the Longxi earthquake should take place on December 13, AD 134 （the third year of Yangjia reign）. As a rough assessment, the epicenter was in Tianshui area and the magnitude was about 7. Due to the political corruption and inability to scientifically explain earthquake phenomenon at the end of Eastern Han Dynasty, a tragedy occurred during the later years of ZHANG Heng＇s life that had direct relations with the earthquake successively occurred in AD 133 and AD 134 after invention of seismometer in AD 132. In order to analyze the ground motion at Lingtai caused by the event in AD 134, the digital broad-band seismic records of three Longxi earthquakes in recent years recorded by Luoyang seismic station are used. The numerical modelings are made from three aspects of seismic magnitude definition, digital broad-band seismograms and empirical Green＇s function method. The results have shown that the maximum horizontal displacement at Lingtai is between 6-8 mm, and the maximum acceleration is less than 10^-2 m/s^2. These results have played an important role in quantitative test of the scientific reconstruction model of ZHANG Heng＇s Seismometer.展开更多
基金National Natural Science Foundation of China (40372086)"Short-term and Imminent Tracing Research of Moder-ate-strong Earthquakes in the SN Seismic Belt" by China Earthquake Administration and Scientific Key Foundation Item of Gansu Province (2GS054-A44-015).
文摘On the basis of the textual research on the historical earthquake data and the field investigation of Wudu earthquake occurred in 186 B.C., we suggest that the earthquake parameters drawn from the present earthquake catalogs are not definite and amendments should be made. The heavily-damaged area of this earthquake should be located between Jugan township of Wudu County and Pingding township of Zhouqu County. Its epicenter should be in the vicinity of Lianghekou in Wudu County with a magnitude of about 7-7 1/4 and an intensity of about IX-X. The major axis direction of the heavily-damaged area should be in the WNW direction that is approximately consistent with the strike of the middle-east segment of Diebu-Bailongjiang active fault zone, and the origin time should match up to that of the latest paleoearthquake event [before （83±46） B.C.] obtained by the trench investigation. Certain seismic rupture evidences are still preserved on this fault segment. Therefore, we propose on the basis of comprehensive analysis that the causative structure of the M 7-7 1/4 Wudu earthquake in 186 B.C. should be in the middle-east segment of Diebu-Bailongjiang active fault zone.
基金Joint Seismological Science Foundation of China (104133)
文摘Longxi earthquake was the only earthquake example, which ZHANG Heng＇s Seismometer had detected. Therefore this event attracted the attention of the academic circle and also served as crucial evidence to examine the rationality of the reconstructed model of the seismometer. But for a long time, owing to the fact that the Jincheng-Longxi earthquake on February 28, AD 138 was mistaken as the event went against the historical records, it was refuted by the researches of both in China and abroad. By making careful textual research of historical records, especially by analyzing the description of Longxi earthquake of Houhan Shu, by studying the historical background exposed by historical literatures at that time, ZHANG Heng＇s biography, his poems and place names of Han Dynasty, by comparing five earthquakes occurred in Qing Dynasty and their attenuation of seismic intensity, the conclusion can be drawn that the Longxi earthquake should take place on December 13, AD 134 （the third year of Yangjia reign）. As a rough assessment, the epicenter was in Tianshui area and the magnitude was about 7. Due to the political corruption and inability to scientifically explain earthquake phenomenon at the end of Eastern Han Dynasty, a tragedy occurred during the later years of ZHANG Heng＇s life that had direct relations with the earthquake successively occurred in AD 133 and AD 134 after invention of seismometer in AD 132. In order to analyze the ground motion at Lingtai caused by the event in AD 134, the digital broad-band seismic records of three Longxi earthquakes in recent years recorded by Luoyang seismic station are used. The numerical modelings are made from three aspects of seismic magnitude definition, digital broad-band seismograms and empirical Green＇s function method. The results have shown that the maximum horizontal displacement at Lingtai is between 6-8 mm, and the maximum acceleration is less than 10^-2 m/s^2. These results have played an important role in quantitative test of the scientific reconstruction model of ZHANG Heng＇s Seismometer.
