新疆全区和分区地壳速度模型的分析

Study on crustal velocity model in Xinjiang and its subareas

首先分析了新疆地震台网长期使用的“3400走时表”,并拟合得到了符合该走时表的速度结构模型.然后对新疆地区2009年1月～2013年12月间记录的所有地震震相数据进行了速度拟合,并对速度的可靠性和稳定性进行了模拟分析.提出了根据地震密集区域划分和建立分区地壳速度模型的概念.采用以2014年新疆于田MS7.3地震为中心、半径为1°范围内、自2009年1月以来所有地震事件的震相数据,拟合了适合于于田的地壳速度模型,该模型在于田MS7.3地震的精定位和地震序列的震源深度确定中得到了应用.

Study of crustal velocity model is very important basic work.It has a long span of 16°from south to north,and 17° from east to west in Xinjiang.Three mountains and double basins,the special topography and complex geological structure have a great influence on the average crustal velocity model of the Xinjiang area.The paper analyzed the 3400 travel time table that has been used in Xinjiang,and obtained the most suitable velocity structure model of the travel time table after fitting.Then a velocity fitting was made by using all data of seismic phase from January 2009 to December 2013,and a simulation analysis of velocity reliability and stability followed.A concept that subarea crustal velocity mode of earthquake concentration area was proposed.Based on all the historical records of earthquake from January 2009 in the area within a radius of 1 ° with the Yutian MS7.3 earthquake as the center,crustal velocity model suitable for Yutian area is fitted.The model has been applied in the fine positioning of Yutian MS7.3 earthquake and the depth of earthquake sequence,and achieved very good results.The process can be used in similar studies.