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Title:: Anomaly of Fault Deformation and Characteristics of Strong Earthquakes in Yunnan Region

Author(s):: LIU Qiang¹; 2; CHEN Yan²; WANG Yong-an²; (1.School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,Anhui,China)(2.Earthquake Administration of Yunnan Province,Kunming 650224,Yunnan,China)

Keywords:: fault deformation; anomaly parameter R; strong earthquake prediction index; Yunnan region

摘要:: 运用1983～2009年云南地区跨断层短水准短基线观测资料,研究了该时段3组7次M≥6.5地震(澜沧—耿马M7.6、M7.2,孟连M7.3、武定M6.5、丽江M7.0,姚安M6.5、缅北M7.0)的形变前兆特征。以断层运动速率与基准值之比定义异常参数R,定量分析了异常与本区域强震的关系,提出强震预测指标。结果表明,R值出现异常后0.5～16个月,川滇菱块内发生M≥6.5或菱块外围400 km范围内发生M≥7.0,并表现出不同的异常特征。菱块外强震前比菱块内强震前R值异常出现时间早,异常持续时间较长; 菱块外强震前R为正值异常,菱块内强震前R为负值异常。研究结果对预测云南地区M≥6.5强震有一定的应用价值。

Abstract:: The deformation precursor characteristics of 7 earthquakes(Lancang M7.6,Gengma M7.2,Menglian M7.3,Wuding M6.5,Lijiang M7.0,Yao-an M6.5,North Myanmar M7.0)in 3 groups for M≥6.5 in the corresponding period were studied by using the crossfault deformation data from 1983 to 2009 in Yunnan region,and the relation between the anomalies and strong earthquakes in Yunnan region was analyzed quantitatively by taking the ratio of deformation rate to datum value as the anomaly parameter R value,and strong earthquake prediction indexes were brought up.The results show that M≥6.5 earthquakes in the interior or M≥7.0 earthquakes in outside area for ranging 400 km of Sichuan-Yunnan Rhombic Block occur in 0.5～16 months after the anomaly parameters R value,which displays distinguishing features.Anomaly parameter R appears earlier and longer for the time of duration outside than interior earthquakes of Sichuan-Yunnan Rhombic Block,and appears positive anomaly before outside strong earthquakes and negative anomaly before interior earthquakes.This paper is valuable for M≥6.5 strong earthquake prediction in Yunnan region.