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...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～Ⅸ, 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 Qinling 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
20世纪20年代,青藏高原东北发生了两次8级以上强震,其中1920年12月16日发生的海原M8.5地震距今已经100年。海原断裂带作为青藏高原东北缘最活跃的断裂带之一,至今仍控制着该区域微震及中强地震活动。本文基于ISCE软件和StaMPS平台,以201...20世纪20年代,青藏高原东北发生了两次8级以上强震,其中1920年12月16日发生的海原M8.5地震距今已经100年。海原断裂带作为青藏高原东北缘最活跃的断裂带之一,至今仍控制着该区域微震及中强地震活动。本文基于ISCE软件和StaMPS平台,以2017年3月至2020年6月覆盖研究区的72景哨兵一号(Sentinel-1)SAR影像为数据源,采用PS-InSAR技术对海原断裂带进行时序形变监测,并以区域内GPS速度场进行校正,获取了其三年多来雷达视线向(Line of sight,LOS)的年平均形变速率。研究结果表明:①海原断裂带南北两盘形变速率差异明显,这与左旋走滑的运动性质相符;②毛毛山断裂、老虎山断裂西段处于闭锁状态,老虎山断裂中东段处于较为活跃状态,观测到蠕滑变形;海原地震破裂带部分断裂浅部处于愈合状态;③老虎山断裂中东段的蠕滑变形是青藏高原东北缘最为显著的区段,推断与1888年和1990年景泰的两次六级地震有关。展开更多
According to a new investigation in the northern Hexi corridor,the remains of two surface rupture zones were discovered on the southern margin fault of the Helishan. One rupture has a length of approximately 7km and t...According to a new investigation in the northern Hexi corridor,the remains of two surface rupture zones were discovered on the southern margin fault of the Helishan. One rupture has a length of approximately 7km and the other 10km. The two surface rupture zones might have been produced by the latest earthquake event. On the surface rupture is continuous scarp and free face caused by the rupture. The scarp is about 1 ～ 1. 5m high and on some sites,nearly up to 2m. According to the OSL results,the latest T1 terrace and higher flood plain forming in 3000a B. P. are dislocated by the fault. The above reveals the rupture age to be later than the T1 terrace. However,in the historical data and earthquake catalogue,we didn't find related information about the fault and surface rupture in this area. The 180 A. D. Biaoshi M8. 0 earthquake and the 756 A. D. Zhangye-Jiuquan M7. 0 earthquake are documented in historical data. It is inferred by textual research that the two earthquakes are related to the northern marginal fault of Yumushan in the south of the basin. Due to a lack of reliable evidence,there are still many arguments on this inferred conclusion. Thus we hold that the two surface rupture zones were produced by one of the two large earthquakes or other unrecorded historical event. The research on the activity and surface rupture of this fault can offer valuable information for the tectonic study and strong earthquake risk estimates of this region in the future.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
The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Xizang (Tibet) Plateau. The Maqu fault is the easternmost segment of the East Kunlun active fault. Bas...The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Xizang (Tibet) Plateau. The Maqu fault is the easternmost segment of the East Kunlun active fault. Based on three trenches, four Holocene palaeo-earthquake events are identified along the Maqu fault. The latest palaeo-earthquake event is (1730±50) ～ (1802±52) a BP, the second is (3736±57) ～ (4641±60) a BP, the third is (8590±70) a BP, and the earliest is (12200±1700) ka BP. The time of the first and second palaeo-earthquake events is more reliable than that of the third and last ones. As a result, the recurrence interval of the palaeo-earthquakes on the easternmost segment of the East Kunlun active fault is approximately 2400 a, and the palaeo-earthquake elapsed time is (1730±50) ～ (1802±52) a BP.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～Ⅸ, 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 Qinling 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.
文摘20世纪20年代,青藏高原东北发生了两次8级以上强震,其中1920年12月16日发生的海原M8.5地震距今已经100年。海原断裂带作为青藏高原东北缘最活跃的断裂带之一,至今仍控制着该区域微震及中强地震活动。本文基于ISCE软件和StaMPS平台,以2017年3月至2020年6月覆盖研究区的72景哨兵一号(Sentinel-1)SAR影像为数据源,采用PS-InSAR技术对海原断裂带进行时序形变监测,并以区域内GPS速度场进行校正,获取了其三年多来雷达视线向(Line of sight,LOS)的年平均形变速率。研究结果表明:①海原断裂带南北两盘形变速率差异明显,这与左旋走滑的运动性质相符;②毛毛山断裂、老虎山断裂西段处于闭锁状态,老虎山断裂中东段处于较为活跃状态,观测到蠕滑变形;海原地震破裂带部分断裂浅部处于愈合状态;③老虎山断裂中东段的蠕滑变形是青藏高原东北缘最为显著的区段,推断与1888年和1990年景泰的两次六级地震有关。
基金supported by the Joint Earthquake Science Foundation (B07007)the Foundation of Base Science of Institute of Geology,CEA (DFIGCEA0607122)the Foundation of State Key Laboratory of Earthquake Dynamics (LED0607)
文摘According to a new investigation in the northern Hexi corridor,the remains of two surface rupture zones were discovered on the southern margin fault of the Helishan. One rupture has a length of approximately 7km and the other 10km. The two surface rupture zones might have been produced by the latest earthquake event. On the surface rupture is continuous scarp and free face caused by the rupture. The scarp is about 1 ～ 1. 5m high and on some sites,nearly up to 2m. According to the OSL results,the latest T1 terrace and higher flood plain forming in 3000a B. P. are dislocated by the fault. The above reveals the rupture age to be later than the T1 terrace. However,in the historical data and earthquake catalogue,we didn't find related information about the fault and surface rupture in this area. The 180 A. D. Biaoshi M8. 0 earthquake and the 756 A. D. Zhangye-Jiuquan M7. 0 earthquake are documented in historical data. It is inferred by textual research that the two earthquakes are related to the northern marginal fault of Yumushan in the south of the basin. Due to a lack of reliable evidence,there are still many arguments on this inferred conclusion. Thus we hold that the two surface rupture zones were produced by one of the two large earthquakes or other unrecorded historical event. The research on the activity and surface rupture of this fault can offer valuable information for the tectonic study and strong earthquake risk estimates of this region in the future.
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The project wasjointlysupported bythefollow-up projectsof moderately strong earthquake prediction of the North-South earthquake zone of China Earthquake Administration,theJoint Earthquake Science Foundation of CEA (104073) and the National Natural science Foundation of China(40372086) .Contribution No.LC20060016 of Lanzhou Institute of Seismology of CEA
文摘The East Kunlun active fault is an important NWW-trending boundary fault on the northeastern margin of the Qinghai-Xizang (Tibet) Plateau. The Maqu fault is the easternmost segment of the East Kunlun active fault. Based on three trenches, four Holocene palaeo-earthquake events are identified along the Maqu fault. The latest palaeo-earthquake event is (1730±50) ～ (1802±52) a BP, the second is (3736±57) ～ (4641±60) a BP, the third is (8590±70) a BP, and the earliest is (12200±1700) ka BP. The time of the first and second palaeo-earthquake events is more reliable than that of the third and last ones. As a result, the recurrence interval of the palaeo-earthquakes on the easternmost segment of the East Kunlun active fault is approximately 2400 a, and the palaeo-earthquake elapsed time is (1730±50) ～ (1802±52) a BP.
