2014年10月2日青海乌兰5.1级地震震源机制、震源深度的确定*
李国佑1,姚家骏2

(1.青海省地震局,青海 西宁 810000; 2.中国地震局地球物理勘探中心,河南 郑州 450002)

乌兰5.1级地震; CAP方法; sPn震相

The Determination of Focal Mechanism and Focal Depth of the Wulan Earthquake,Oct.2,2014
LI Guoyou1,YAO Jiajun2

(1.Earthquake Administration of Qinghai Province,Xining 810000,Qinghai,China)(2.Geophysical Exploration Center of Chinese Earthquake Administration,Zhengzhou 450002,Henan,China)

Wulan MS5.1 earthquake; CAP method; sPn phase

备注

利用2014年10月2日青海乌兰5.1级地震震中周边宽频带波形资料,采用CAP方法反演了该地震的震源机制解和震源深度,结果表明:乌兰5.1级地震是一次逆冲型地震,最佳双力偶解为节面I走向279°、倾角48°、滑动角81°; 节面Ⅱ走向112°、倾角43°、滑动角100°,最佳矩心深度为15 km。采用波形互相关方法拾取Pn波,应用滑动时窗相关法识别sPn震相,通过sPn与Pn震相之间的走时差进一步确定本次地震的震源深度。

On October 2,2014,a MS5.1 earthquake occurred in Wulan,Qinghai province.Using the local broadband waveform data of available stations in regional seismic networks,the focal mechanism and focal depth were determined by the “Cut and Paste”(CAP)method at first.The best double couple solution is 279°,48°,81°for strike,dip and slip angles,respectively for one nodal plane,and 112°,43°,100° for another nodal plane,the estimated focal depth is about 15 km.In order to better constrain the focal depth,we further refined it with depth sPn phase by using the arrival-time differences between Pn and sPn phases,which were picked by the waveform cross-correlation and sliding-window correlation method.The difference between the two methods was within 0.5 meters.