[CIG-SEISMO] SPECFEM3D how to set magnitude of vertical force

[Andrea Colombi]

Hello,
I am trying to use specfem3D for a sort of unusual purpose compared to its
traditional use. I am replicating small scale laboratory experiments about
wave-propagation on metal-plate with scatterers and 3D features embedded
or attached to it. I have been working for a while and the results seems
overall good. One thing still remain not clear to me: how to set the right
force magnitude to the source?

The source I want to emulate acts in the vertical direction (perpendicular
to the plate, Z-axis) and it applies a load of the order of 0.1N. How can i
set this value? The code seems to ignore the moment tensor parameter when i
am using a point force and rather using the "FACTOR_FORCE_SOURCE".  I have
been following a recent discussion (september), which confirmed that by
tweaking the code myself i went to the right direction, I disabled the
original Ricker for the Heaviside. Those are the settings I have been using
in the constant.h file so far:


logical, parameter :: USE_FORCE_POINT_SOURCE = .true.

double precision, parameter :: FACTOR_FORCE_SOURCE = 1.d4
integer, parameter :: COMPONENT_FORCE_SOURCE = 3  ! takes direction in comp
E/N/Z = 1/2/3

and regarding the receivers:

logical, parameter :: EXT_MESH_RECV_NORMAL = .true.

I have no UTM projection active and the source is a Dirac pulse (or better
an Heaviside) as it is originally implemented in the code, i.e. reading the
netlib error function. Frequency are high (10Khz).
Thanks for the help and best regards

Andrea Colombi
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