Research On The Characteristics And Correlation Of Ground Fissure And Earthquake Activities In Hebei Plain

The Hebei Plain is one of the most intense areas of ground fissure activities in China.At present,many experts and scholars have made a series of important achievements in the study of the distribution regularity and disaster-induced mechanism of ground fissure and earthquake in Hebei Plain.However,these studies have made ground fissures and seismicity as two isolated Geological disasters to carry out research and analysis,in situ cracks and seismicity related research little.and there are few studies on the correlation between ground fissure and earthquake activities.Available data and field investigation show that 80% of the Hebei Plain ground fissure for fault creep crack,The developmental degree?causative way and activity mode are closely related to the active fault,regional tectonic stress field and earthquake.Combined with the impact of the seismic belt in the Hebei Plain,the seismic activity is more frequent.Therefore,The research on the characteristics and correlations of ground fissures and seismicity in Hebei Plain is of great significance to the monitoring and early warning of ground fissures and earthquake disaster in Hebei plain.Firstly,On the basis of the investigation and data collection of the ground,the comprehensive collation and analysis of the fissures in the hebei plain as of 2016 were carried out.the paper plotted the distribution of the ground fissure in 1:500,000 Hebei Plain,systematically expounded the causes,plane and spatial distribution characteristics and activity characteristics of the ground fissure;Secondly,Based on the analysis of the integrity of the earthquake catalogs from 1970 to 2016 in Hebei Plain,the seismic activity characteristics of Hebei plain and typical areas were studied;Finally,Based on the temporal and spatial distribution characteristics and the activities characteristics of ground fissures and seismicity in Hebei plain,the correlations of ground fissures and seismicity are systematically discussed and analyzed.The study found:(1)By 2016,there are more than 837 fissures in the Hebei Plain,of which more than 80% are tectonic fissures,mainly concentrated in the period from 1985 to 2011,with mass characteristics.The ground fissure are mainly distributed in the northwest and central of Hebei Plain.and the basement structure is concentrated on the planar distribution.Mainly along the middle of the Jizhong sag and its junction with Taihang Mountain uplift,Yanshan uplift,More is corresponds to ground fissure ?active fault zone and seismic belt,and is often controlled by the active fault zone,partially cracks in contact with the lower-volt active faults,with sedimentary growth fault properties.(2)Hebei Plain in the Hebei plain earthquake belt,from 780 BC to January 2016,ML2.0 more than a total of 5694 earthquake,In the history of 1679 occurred in the three rivers Pinggu 8 earthquake,1830 Cixian 7 magnitude earthquake,and since March 8,1966 Xingtai 6.8 and March 22 Xingtai 7.2 earthquake,the Hebei Plain earthquake activity into an active period,followed by the 1967 Hejian City 6.3 Earthquake,1976 Tangshan City,7.8 earthquake.The above record earthquake shows that Hebei Plain area at this stage of the new tectonic activity is very strong,the seismicity showed high frequency,strength characteristics.(3)The relation between the ground fissure and earthquake in the research area is mainly reflected in the following two aspects: First,the earthquakes and the strong earthquakes show significant temporal and spatial consistency,specifically for the ground fissures and seismic activity of the spatial and temporal distribution of synchronization and unity,such as Xingtai,Tangshan,Hejian earthquake ground fissures.Second,tectonic creep ground fissure and microseismic activities show significant temporal and spatial differences,specifically for the ground and seismicity and spatial distribution of seismic activity is different and complementary,such as Handan ground fissure.(4)According to the spatial and temporal distribution of ground fissures and earthquakes,ground fissure and earthquake activities can be divided into three stages: 1966-1978 “north earthquake and south ground fissure” stage in Hebei Plain,in which 1966-1972 the early North earthquake south fissure phenomenon,accompanied by 1966 two large earthquake,large area cracks appeared in the southern Plains of Hebei,1973-1978 north earthquake and south ground fissure reached climax;1979-1988,“South earthquake and north ground fissures” stage,manifested in the July 1979 Liyang 6 earthquake,the May 1984 River Zhuo Sand 6.3 earthquake,and the northern Plains of Hebei in the cracks during the activity reached climax;Since 1989,“North earthquake and south ground fissure”stage;The performance of the southern Hebei province in 1990 in Zhao County Dingcun,1998 Dingcun,Zhao Village and other places to develop a large-scale ground fissures,and seismic activity is mainly concentrated in the north.Therefore,the comprehensive above,Hebei Plain can be summarized as " earthquake in the north,ground fissure in the south," and " earthquake in the south,ground fissure in the north," seismic activity area and the ground fissure activity center area alternating regularity.