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SPECFEM / specfem2d

SPECFEM2D simulates forward and adjoint seismic wave propagation in two-dimensional acoustic, (an)elastic, poroelastic or coupled acoustic-(an)elastic-poroelastic media, with Convolution PML absorbing conditions.
https://specfem.org
GNU General Public License v3.0
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Problem with the dominant frequency after looking at the frequency spectrum of the seismogram. #1169

Closed rashi-13 closed 1 year ago

rashi-13 commented 2 years ago

Hello

I have specified the dominant frequency (f0) as 27 Hz in the "SOURCE" file and source type as ricker wavelet (specified as source_type = 1) in the "./DATA/SOURCE" file .

I ran the solver and got the seismograms for one source and 24 receivers. I combined them and looked at the shot gather. Then i looked at the frequency spectrum of the shot gather and found the dominant frequency (Peak) at 37Hz.

Also, irrespective of changing f0 (dominant frequency) to 20Hz /30Hz /27 Hz, i am getting the same spectrum of the seismogram.

Am i making some mistake while running the solver? Do i need to look for some more parameters for the frequency?

Please help me out.

rashi-13 commented 1 year ago

i am closing this issue since i am able to figure out the problem myself.

It was the depth of the model where absorbing boundary conditions were applied and hence energy was not getting reflected back (hence no desired frequency corresponding to the given depth parameter).