云南地区地震目录最小完整性震级研究*

(1.云南省地震局,云南 昆明 650224; 2.新疆维吾尔自治区地震局,新疆 乌鲁木齐 830011; 3.中国地震局地球物理研究所,北京 100081)

地震目录; 最小完整性震级; 地震监测效能; 震级—频度分布

Research on Minimum Magnitude of Completeness for Earthquake Catalogue in Yunnan Region
LIU Li-fang1,LI Zhi-hai2,JIANG Chang-sheng3

(1. Earthquake Administration of Yunnan Province,Kunming 650224,Yunnan,China)(2. Earthquake Administration of Xinjiang Uygur Autonomous Region,Urumqi 830011,Xinjiang,China)(3. Institute of Geophysics,CEA,Beijing 100081,China)

earthquake catalogue; minimum magnitude of completeness; seismic monitoring capability; magnitude-frequency distribution

备注

通过对构造活动强烈、地震活动频度高、台站分布极不均匀的云南地区开展最小完整性震级MC研究,试图为地震危险性评估和台站科学布局等研究提供参考资料。基于云南区域地震台网发展阶段,利用基于G-R关系的交互式分析方法,研究了MC的空间分布特征; 采用多参数方法研究了云南8个地震区(带)的MC时间演化特征。结果 表明:云南区域台网不同发展时段MC的空间分布存在较大的非均匀性,大理—丽江—盐源区、元谋区、小江带等区(带)监测能力较好,澜沧—耿马区、思普区等区(带)监测能力较低。但云南“十五”区域数字地震台网运行以来,云南省MC可达ML1.5左右,其中大理—丽江—盐源区MC可控制在ML1.0~1.5,小江带MC约为ML1.5,腾冲—龙陵区MC可控制在ML1.0~2.0,澜沧—耿马区MC可控制在ML1.5~2.5,思普区MC约为ML1.0~2.0。云南地区8个地震区(带)MC时间变化特征分析结果表明,增加台站数量,优化台网布局,是提升云南地区地震监测能力的有效途径。

We study the minimum magnitude of completeness MC in Yunnan with intense tectonic movement,high frequent of earthquake activity and non-uniform distribution of seismic stations,which could provided useful information for seismic risk evaluation and scientific layout of seismic stations etc.. On the basis of development stage of Yunnan Regional Network(YRN),we studied the spatial distribution feature by using interactive analysis method based on the G-R relation and investigated temporal variation of MC in 8 seismic zone in Yunnan by means of multi-parameter description. The result shows that in different stage of YRN,MC is distributed inhomogeneously; the monitoring capability of YRN in Dali-Lijiang-Yanyuan zone,Yuanmou zone,and Xiaojiang earthquake belt is strong,but weak in Lancang-Genma zone,Simao-Pu'er belt,etc.. Since the running of YRN improved during the Tenth Five-year Plan(2001-2005),MC in Yunnan reached ML1.5 or so,ranged between ML1.0-1.5 in Dali-Lijiang-Yanyuan zone,ML1.5 in in Xiaojiang zone,ML1.0-20 in Tenchong-Longling,ML1.5-2.5 in Lancang-Genma,and ML1.0-2.0 in Simao-Pu'er. The temporal variation of MC for 8 seismic zones shows that adding stations and optimizing network are the effective ways for improving seismic monitoring capability in Yunnan region.