地震分析软件SAC
C-1. 针对IzmitMw7.4和 DuzceMw7.1地震，写出完成以下功能的命令操作
# lunch sac
# read the vertical-component data recorded by station BV
# plot the data
# read all three component data recorded at station BV
# plot multiple data in one page
# zoom in at 0 - 7 s relative to the waveform reference time (typically the origin time)
# you have to plot it again to reflect the change
# zoom in at 2 s before P, and 4 s after S arrivals
# enforce that y axis has the same scale
# you have to plot it again to reflect the change
# quit sac
C-2. 把SAC数据写回磁盘，写出完成以下功能的命令操作
cp DATA/*.BV.*z* CYC.BP # make a backup of the vertical data
sac # lunch sac
read DATA/*.YJ.BV.EHZ.SAC# read the data file YJ.BV.EHZ.SAC
plot # plot it out
remean # remove the mean
w DATA/*BV*Z*.SAC # overwrite the data back to the disk (using the original name YJ.BV.EHZ.SAC)
w DATA/temp.SAC # Write the data back to the disk using a new name temp.sac
quit #quit sac
rm DATA/temp.SAC # clean up what just created.
cd DATA ls # restore the original data
C-3.列出SAC头文件，写出完成以下功能的命令操作
sac # launch sac again
read DATA/*.YJ.BV.EHZ.SAC # read the data YJ.BV.EHZ.SAC
LISTHDR # list the SAC header
LISTHDR evla evlo stla stlo # list the SAC header evla evlo stla stlo
C-4.对地震记录进行旋转，写出完成以下功能的命令操作
DATA/YJ.BV.EHN.SAC # read the north component seismogram
CHNHDR EVLA 0 EVLO 90# change the incident and azimuth of the instrument to be north and horizontal
w YJ.BV.EHN.SAC # save the header (the above three lines are not needed if the headers are already in)
r DATA/YJ.BV.EHE.SAC # read the east component seismogram
CHNHDR EVLA 90 EVLO 90# change the incident and azimuth of the instrument to be east and horizontal
w YJ.BV.EHE.SAC # save the header (the above three lines are not needed if the headers are already in)
w YJ.BV.*Z.SAC # read two horizontal component seismograms
rotate to gcp # rotate to the "great circle path"
w *.*.BV.* # save the rotated data (first radial, second transverse)
r *.*.BV.* # read three-component seismograms (vertical, radial and transverse)
xlim pdw # zoom in
p1ot # plot them out, try to identify Love and Rayleigh waves
C-5．设计不同的滤波器计算FFT，写出完成以下功能的命令操作
r *.PKD.* # read the transverse-component data recorded at station PKD
rmean # remove the mean
bp 2:8 # apply two-way 2-8 Hz band-pass-filter to the data
w BK.PKD.HHT.SAC.bp # save the band-pass-filtered data as BK.PKD.HHT.SAC.bp
r BK.PKD.HHT.SAC.bp # read the original data again
p1ot # plot the band-pass-filtered data
cut on # cut the data
r BK.PKD.HHT.SAC.bp # read the data again
rmean # remove the mean
taper type hanning width 0.05 # apply a hanning window to the 0.05 width of the data
fft wmean amph # compute FFT
keepam # keep only the amplitude information (and throw the phase information)
p1ot # plot the amplitude spectrum
loglog # use the log-log plot
xlim on # set the x-axis plot range (Frequency)
p1ot # plot again in log-log scale
C-6.震相拾取，写出完成以下功能的命令操作
cut on# cut the data
r *.BV.*.SAC# read three component data recorded at station BV
p1ot # plot the data
ch a undef # remove the original P and S arrival pick
apk VALIDATION ON # use the auto picker
p1ot # see the auto picker result
ppk om # use the manual picker
ppk v3 # pick all 3 component together with the same time, turn the annoying bell off
wh 4 #to save the picked arrival, you can use the command "wh". But this command could mess up the data if you have used the cut command. So be careful
C-7.编写一个SAC宏文件，完成以下功能
sac # launch sac
read *.BV.*.SAC # read all three component data recorded at station BV
mul 4 5 6# multiply data 4,5 ,6 respectivly
fft wmean amph # Fourier transform
quit # quit sac
