According to the detailed study of the historical earthquake records and causative structure of the Minxian M6 1/2 earthquake in 1573 A.D., we have found that the most grievous disaster area lies nearby the Minxian co...According to the detailed study of the historical earthquake records and causative structure of the Minxian M6 1/2 earthquake in 1573 A.D., we have found that the most grievous disaster area lies nearby the Minxian county seat （Minzhou county at that time ）. So, we have identified the extremely seismic area of the 1573 A.D. The Minxian M6 1/2 earthquake was located in Minxian city, the intensity of the meizoseismal region is Ⅷ - Ⅳ, the epicenter is 34.4°N, 104.0°E, the location precision is Ⅱ and the deviation of location is less than or equal to 25km. Tectonically, this area lies in the transition region of stress transfer and structural transform between the east Kunlun fault and the northern margin of the west Qiuling fault. The differential activity of the Lintan-Dangchang fault zone is obvious, and only parts of the segment put up Holocene activity. There are landslides and rock bursts of different sizes in the meizoseismal region. By integrated analysis, we conclude that the Minxian-Dangchang segment of the Lintan-Dangchang fault is the seismogenic structure of the 1573 A.D. M6 1/2 Minxian earthquake, in Gansu Province.展开更多
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
According to historical records,in July of 1590 A.D.,a destructive earthquake occurred near Lintao county in Gansu Province,in which "… city walls and houses collapsed,and countless people and domestic animals w...According to historical records,in July of 1590 A.D.,a destructive earthquake occurred near Lintao county in Gansu Province,in which "… city walls and houses collapsed,and countless people and domestic animals were killed".In the same month,Binggou town in eastern Qinghai Province(now northeastern Ledu county),was also damaged by an earthquake.These two earthquakes were listed as two different cases in the published earthquake catalogues,recorded separately as the Lintao M_S5.5 earthquake with epicentral intensity Ⅶ in Gansu Province and the Ledu M_S5.0 earthquake with epicentral intensity Ⅵ in Qinghai Province.However,based on comprehensive analysis of research on historical records and field investigations,it is concluded in this paper that these two earthquakes could be the same one with magnitude 6.5 and epicentral intensity Ⅷ～Ⅸ.Its epicenter was in the Maxian Mt.,which is located in southeastern Yongjing and its seismogenic structure might be the mid-western segments of the north fringe fault zone of Maxian Mt.of Lanzhou.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
研究历史地震事件是认识地震活动规律、分析发震构造的重要途径之一。1568年5月25日(隆庆二年四月十九日申时),在西安东北高陵地区发生一次强烈地震,造成各类建筑物倒塌毁坏"尽如平地","人畜伤亡甚众"。此前的地震...研究历史地震事件是认识地震活动规律、分析发震构造的重要途径之一。1568年5月25日(隆庆二年四月十九日申时),在西安东北高陵地区发生一次强烈地震,造成各类建筑物倒塌毁坏"尽如平地","人畜伤亡甚众"。此前的地震目录将这次地震命名为陕西西安东北地震,震级为6级,极震区烈度为Ⅸ。文中通过对历史地震资料的再考证及野外调查,认为该次地震的极震区位于在泾河以北的泾阳县东南的永乐镇、高庄镇北部至高陵县及其东南姬家乡、张卜乡一带,并命名为陕西高陵地震,烈度为Ⅸ+(Ⅸ～Ⅹ)度,估算其震级可达7级。同时,对震害进行了细致分析并重绘制了该地震的等震线图,得到其极震区的位置,同时发现其等震线长轴为NWW向,与渭南-泾阳断裂相吻合。该断裂为全新世活动正断层,沿断裂地貌保留了部分断错阶地陡坎,断层剖面中可见砂土液化、张性构造裂缝等新活动遗迹,最晚活动时间为(180±30) a BP至(1 600±30) a BP之间。文中分析认为1568年陕西高陵7级地震的发震构造为渭南-泾阳断裂,该断裂与渭南塬前断裂、华山山前断裂共同构成渭河盆地东南缘的重要边界活动断裂带。展开更多
基金This research was sponsored bythe sub-project entitled "Active Tectonic Framework and Assessment of Tendency of Seismic Riskinthe Key Earthquake Risk Regionsin Gansu,Sichuan and Qinghai Provinces"under the"Special project of emergent intensive observation of earthquake situation onthe north-south earthquake zone"of China Earthquake Administration and the Joint Earthquake Science Foundation of CEA under grant number 604018.Contribution number :LC20060042 of Lanzhou Institute of Seismology,CEA.
文摘According to the detailed study of the historical earthquake records and causative structure of the Minxian M6 1/2 earthquake in 1573 A.D., we have found that the most grievous disaster area lies nearby the Minxian county seat （Minzhou county at that time ）. So, we have identified the extremely seismic area of the 1573 A.D. The Minxian M6 1/2 earthquake was located in Minxian city, the intensity of the meizoseismal region is Ⅷ - Ⅳ, the epicenter is 34.4°N, 104.0°E, the location precision is Ⅱ and the deviation of location is less than or equal to 25km. Tectonically, this area lies in the transition region of stress transfer and structural transform between the east Kunlun fault and the northern margin of the west Qiuling fault. The differential activity of the Lintan-Dangchang fault zone is obvious, and only parts of the segment put up Holocene activity. There are landslides and rock bursts of different sizes in the meizoseismal region. By integrated analysis, we conclude that the Minxian-Dangchang segment of the Lintan-Dangchang fault is the seismogenic structure of the 1573 A.D. M6 1/2 Minxian earthquake, in Gansu Province.
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sponsored by the Active Faults Exploration and Seismic Risk Assessment in Lanzhou City,a National Tenth"Five-Year Plan"Significant Project,and Scientific and Technological Key Project in Gansu Province(2GS054-A44-015)Treatise No.of Lanzhou Institute of Seismology,CEA:LC20070037
文摘According to historical records,in July of 1590 A.D.,a destructive earthquake occurred near Lintao county in Gansu Province,in which "… city walls and houses collapsed,and countless people and domestic animals were killed".In the same month,Binggou town in eastern Qinghai Province(now northeastern Ledu county),was also damaged by an earthquake.These two earthquakes were listed as two different cases in the published earthquake catalogues,recorded separately as the Lintao M_S5.5 earthquake with epicentral intensity Ⅶ in Gansu Province and the Ledu M_S5.0 earthquake with epicentral intensity Ⅵ in Qinghai Province.However,based on comprehensive analysis of research on historical records and field investigations,it is concluded in this paper that these two earthquakes could be the same one with magnitude 6.5 and epicentral intensity Ⅷ～Ⅸ.Its epicenter was in the Maxian Mt.,which is located in southeastern Yongjing and its seismogenic structure might be the mid-western segments of the north fringe fault zone of Maxian Mt.of Lanzhou.
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.
文摘研究历史地震事件是认识地震活动规律、分析发震构造的重要途径之一。1568年5月25日(隆庆二年四月十九日申时),在西安东北高陵地区发生一次强烈地震,造成各类建筑物倒塌毁坏"尽如平地","人畜伤亡甚众"。此前的地震目录将这次地震命名为陕西西安东北地震,震级为6级,极震区烈度为Ⅸ。文中通过对历史地震资料的再考证及野外调查,认为该次地震的极震区位于在泾河以北的泾阳县东南的永乐镇、高庄镇北部至高陵县及其东南姬家乡、张卜乡一带,并命名为陕西高陵地震,烈度为Ⅸ+(Ⅸ～Ⅹ)度,估算其震级可达7级。同时,对震害进行了细致分析并重绘制了该地震的等震线图,得到其极震区的位置,同时发现其等震线长轴为NWW向,与渭南-泾阳断裂相吻合。该断裂为全新世活动正断层,沿断裂地貌保留了部分断错阶地陡坎,断层剖面中可见砂土液化、张性构造裂缝等新活动遗迹,最晚活动时间为(180±30) a BP至(1 600±30) a BP之间。文中分析认为1568年陕西高陵7级地震的发震构造为渭南-泾阳断裂,该断裂与渭南塬前断裂、华山山前断裂共同构成渭河盆地东南缘的重要边界活动断裂带。
