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