图  1   Cove Fort-Sulphurdale地热区域的地质图(引自Steven，Morris，1983)

Solid lines represent faults，dashed lines represent concealed faults that may exist， and rocks of different geological times are indicated in different colors

Figure  1.   Regional geological map for the Cove Fort-Sulphurdale geothermal area(after Steven，Morris，1983)

图  2   Cove Fort-Sulphurdale地区的地震事件和台站分布 灰度代表地形高程(单位： km)，白色表示海拔高

Figure  2.   Seismic events and stations distribution map in Cove Fort-Sulphurdale Red dots denote seismic events and blue triangles indicate stations，grayscale represents the terrain elevation(in km)(white indicates high altitude)

图  3   震源机制反演得到的前９个最大目标函数的解，No.1和No.9 分别表示这９个解中最好和最差的解

Figure  3.   Solutions with the first nine largest objectivefunction values from focal mechanism inversion,where No.1 means the best solution and No.9 means the worst one among these nine solution

图  4   ８个台站的模拟数据（红色点线）与合成数据（蓝色实线）的波形匹配图 左图为P波匹配结果，图中绿色竖线表示P波理论初至时间，零时刻代表记录开始时刻，上、下两个“＋”或“－”分别表示合成数据和模拟数据的P波初动极性；右图为S波匹配结果，零时刻表示计算得到的S波开始时刻，最右侧数值表示横纵波振幅比信息，斜杠左边为合成数据的横纵波振幅比值，斜杠右边为相应的模拟数据的横纵波振幅比值．Δ 表示时移

Figure  4.   Wave form matching between modelled (reddottedlines) and synthetic(bluesolidlines)waveforms at eight stations The left column shows P waves and right column shows S waves.The green lines indicate the calculated first P arrival times.For P waves,zero time means the origin time,“+"or“-"signs indicate the first arrival polarities of P waves inthedata(upper)and those in the synthetics(lower).For the S waves,zero time means the S-wave arrival time predicted by the calculated travel time,the number to the left of the slash denotes the S/P ratio for the data,the number to the right of the slash denotes the ratio for the modelled waveform.Δ indicates the time shift

图  5   一个典型事件的垂向记录(a)及其频谱(b)

Figure  5.   A typical event used in the focal mechanism determination(a) and its spectrograms(b)

图  6   Cove Fort-Sulphurdale地区的一维层状P波和S波速度结构

Figure  6.   1D layered velocity structure of P and S waves for Cove Fort-Sulphurdale

图  7   No.235和No.313地震事件的震源机制解和波形匹配图． 图中说明同图 4

Figure  7.   Focal mechanism solution and waveform matching for the seismic events No.235 and No.313，respectively. The meanings of symbols are the same as those in Fig. 4

图  8   No.234和No.11地震事件的震源机制解和波形匹配图． 图中说明同图 4

Figure  8.   Focal mechanism solution and waveform matching for the seismic events No.234 and No.11，respectively. The meanings of symbols are the same as those in Fig. 4

图  9   20个地震事件的震源机制解

Figure  9.   Distribution of focal mechanisms of 20 seismic events(red dots)determined by the waveform matching method

图  10   Cove Fort-Sulphurdale地区20个地震事件的P轴(红色)和T轴(蓝色)分布  轴线长短表示倾角大小，线段越短表示倾角越大

Figure  10.   Distribution of P(red) and T(blue)axes determined from focal mechanisms of 20 seismic events in the Cove Fort-Sulphurdale area The length of axis indicates inclination with the shorter line representing greater inclination angle

图  11   P轴和T轴倾角统计图

Figure  11.   Distribution of inclination angles for P and T axes

图  12   CDP方法横波分裂分析流程图 (a)ME01A台站的部分原始三分量记录，阴影部分表示用于横波分裂分析的窗口长度；(b)互相关函数值关于快波极化方向和慢波时间延迟的分布图． “+”表示最大互相关函数值，其对应的快波极化方向和慢波时间延迟分别为54°和0.03 s；(c)极化方向确定后，互相关函数值随慢波时间延迟的分布图；(d)旋转到快、 慢波极化方向后的水平分量波形图；(e)经时间延迟校正后的快慢波波形图；(f)慢波时间延迟校正前(左)、 后(右)的质点运动轨迹图

Figure  12.   Shear wave splitting analysis flow chart using CDP method (a)Original three-component seismograms recorded on the station ME01A with the shadow part indicating the length of time window used in the shear wave-splitting analysis.(b)A contour plot of the cross-correlation coefficient values.The maximum cross-correlation coefficient value is indicated by the cross at the fast polarization direction(PD)54° and time delay(TD)0.03 s.(c)A plot of the cross-correlation coefficient values at the measured PD.(d)Seismograms rotated to the estimated fast and slow PDs.(e)Waveforms of the fast and slow components shifted with the measured TD.(f)The horizontal particle motion of the original seismogram(left panel) and that of the fast and slow components shifted with the measured TD(right panel)

图  13   横波分裂分析的所有地震事件的平均时间延迟(a)和各台站快波极化方向(b)

Figure  13.   The average time delay between fast and slow shear waves(a) and the average fast shear wave polarization direction(b)at each station from all of the analyzed events