Paleoearthquake Of Majiamo In Tazang Fault

East Kunlun fault zone is an important fracture in the northeast of Qinghai Tibet Plateau.According to the difference of sliding rate and historical earthquake on both sides of Annemaqen Shan,we divide the fault zone into two parts,the eastern and the western.Sliping rate decreases gradient from west to east,and the rupture caused by historical earthquake in the past hundred years basically covers the western and a part of the eastern.With the continuous occurrence of strong earthquakes in the edge of Bayan La block,the study on seismic gap and seismic potential of East Kunlun fault,which is the north boundary of the block,are becoming more and more important.Maqu segment is in the east of east Kunlun fault,including Maqen-Maqu fault and Tazang fault,and it has big earthquake potential.We already have some research findings in geometrical distribution,sliding rate and paleoearthquake on Maqen-Maqu fault,and research in geometrical distribution and paleoearthquake on Tazang fault has some preliminary findings.In addition,due to the large difference of the slip velocity of the Tazang fault,it is impossible to obtain the reliable paleoearthquake parameters,which limits evaluation accuracy of earthquake potential in Maqu segment,especially Tazang fault.Paleoseismology is one of the key components for the research of active fault,which is important in areas like segmentation of active fault,active intensity contrast,dynamics study(Min Wei,1998).Therefore,it is necessary to study the paleoearthquake of the Tazang fault,and obtain the paleoearthquake parameters of the Tazang fault,which provides a basis for evaluating the seismic potential of the Tazang fault and Maqu segment.This paper mainly studies the paleoearthquakes of the Tazhong fault.3 profiles and 5 trenches in Majiamo,which identified 5 ancient earthquake events in the Majiaimo section: E1:18332~18247(BC),E2:10229~9584(BC),E3:9473~3963(BC),E4:3245~3032(BC),E5:1561~1879(AD).The paleoearthquake recurrence period is 4937 ± 533 a.Due to the existence of sedimentary discontinuities in different sections,the strata of the corresponding era are missing,so there may be paleoearthquake events that are not identified,and the actual recurrence period should be smaller.According to the data in this paper(lack of the Dongbei section),the probability of earthquake occurrence in the next 100 years of the East Kunlun fault is calculated.The probability of the earthquake occurrence of the East and West Datan and Maqu sections in the next 100 years is higher than that of other sections.We should strengthen seismic research in this section and the Dongbei section.