图  1   5个地震台站(三角形)的分布

Figure  1.   Locations of five seismic stations (triangles) used in this study

图  2   地震事件和台站的分布

Figure  2.   Locations of earthquakes (squares) and seismic stations (triangles) used in this study

图  3   HEL台站得到的SKS震相分裂结果

(a) 滤波后的径向和切向分量波形， 灰色区域为所选取的时间窗； (b) 事件的反方位角分布； (c) 利用旋转相关法得到的归一化快慢波波形； (d) 利用旋转相关法得到的径向分量与切向分量的波形； (e) 利用旋转相关法得到的校正前后的水平质点运动图； (f) 互相关系数关于快波偏振方向φ和快慢波时间延迟δt的分布； (g) 利用最小能量法得到的归一化快慢波波形； (h) 利用最小能量法得到的径向分量与切向分量的波形； (i) 利用最小能量法得到的校正前后的水平质点运动图； (j) 切向分量能量关于快波偏振方向和快慢波时间延迟的分布

Figure  3.   An example showing measurement process of SKS waveform recorded by the station HEL

(a) Filtered radial and tangential components with shaded area showing selected time window； (b) Back-azimuth distribution of the event used； (c) Normalized fast and slow waveforms by rotation correlation (RC) method; (d) Comparison of radial and tangential components by RC method; (e) Particle motion before and after correction of anisotropy by RC method; (f) Distribution of correlation coefficients with respect to delay time δt and fast wave orientation φ; (g) Normalized fast and slow waveforms by minimum energy (SC) method; (h) Comparison of radial and tangential components by SC method; (i) Particle motion before and after correction of anisotropy by SC method; (j) Distribution of transverse energy with respect to delay time and fast wave orientation

图  4   有差异的SKS (a)和SKKS (b)震相对分析结果示例

(a) 第一列为SKS震相校正前(虚线)、 后(实线)的质点振动图， 图中给出了相应的横波分裂参数； 第二列为滤 波后的地震记录径向(虚线)和切向分量(实线)， 灰色阴影表示选用的时间窗， 竖直虚线表示横波震相的理论到 时， 图中还给出了台站名和对应的地震事件时间； (b) 相同台站对应的SKKS震相信息， 图例说明与图(a)相同

Figure  4.   Waveform examples of discrepant SKS (a) and SKKS (b) phase-pairs

(a) Left panels are corrected (solid lines) and uncorrected (dashed lines) particle motion for the SKS phase with the measured splitting parameters shown， and right panels are filtered radial (dashed lines) and transverse (solid lines) seismogram components， where the shaded areas represent the selected time window and the vertical dased lines represent theoretical arrval time of seismic shear phases. (b) The corresponding SKKS phase following the same conventions， where the illustrations are the same as Fig.(a)

图  5   GyPSuM成像模型在2700 km深度的剖面

底图的S波层析成像结果引自Simmons et al(2010). 黑色细线连接同一个有差异的SKS-SKKS震相对， 白色细线 连接同一个无差异的SKS-SKKS震相对； 黑色条棒的方向和长度分别代表快波偏振方向和快慢波时间延迟

Figure  5.   Results plotted on GyPSuM model at depth 2700 km

Blue and orange circles denote the phases for discrepant pairs. All nondiscrepant pairs are shown as white circles. Thin lines connect SKS-SKKS pairs (black for discrepant pairs， white for nondiscrepant ones). Measured fast directions and delay times are represented by the orientation and length of black bars， respectively. All discrepant SKS-SKKS pairs plotted atop the GyPSuM tomography model (Simmons et al， 2010). The boundaries (red thick line) of the LLSVP are inferred from travel time analysis and waveform modeling results by He and Wen (2012)

图  6   GyPSuM成像模型在2600 km深度的剖面(S波层析成像结果引自Simmons et al， 2010)

All discrepant SKS-SKKS pairs plotted atop the GyPSuM tomography model (Simmons et al， 2010). The boundaries (red thick line) of the LLSVP are inferred from travel time analysis and waveform modeling results by He and Wen (2012)

Figure  6.   GyPSuM at depth 2600 km