Same seismogram for different stations at different location

[visruthac]

I am getting the same seismigrams for all the stations which are at different locations while using SPECFEM3D Cartesian for different 1D , 2D and 3D models I have tried. What could be the reason for this. How can I obrain the station specific seismograms?

In the EXAMPLES folder also, the seismograms given are the same for each staions.

[bch0w]

Hi @visruthac, this might depend on a few things, such as your source mechanism, station geometry, and station locations. SPECFEM outputs synthetics for each station listed in the DATA/STATIONS file.

Can you provide the source (CMTSOLUTION) and station (STATIONS) file that you are using for your simulation?

It would also be useful if you could note which example you are referring to when you mention all seismograms are the same.

[visruthac]

@bch0w Thank you for your reply.

If you consider the CMTSOLUTION and STATION file given in the EXAMPLES/homogeneous halfspace. I am getting the same seismogram at station for any component , say Z.

The reference seismograms given in the above folder also shows the same.

[bch0w]

That's interesting. I see that the stations are all placed in a line for that example, so for a homogeneous domain I might expect them to have similar waveforms. However, when I plot all the synthetic seismograms together, they do clearly show differences. Can you confirm this is what you're seeing?

Small Python script to plot the output seismograms in the OUTPUT_FILES directory

import numpy
import matplotlib.pyplot as plt

for i in [2,3,4,5]:
    fid = f"DB.X{i}0.BXZ.semd"
    data = np.loadtxt(fid)
    plt.plot(data[:,0], data[:,1], label=fid)
    plt.legend()
    plt.show()

[visruthac]

Hi @bch0w I realised that it was my mistake in reading the output files. Thank you for your help.