This is a modification of gmsim_v16.1.1 based on developments during the work of Robin Lee in 2017/2018. This is the version used in Lee et al. (2019):
...
Due to limitations of the 3D velocity models used, the LF simulation results are not usually output at reference velocities which are equal to the true site velocities. This is the reason empirical CB14 site amplification is used ( in addition to accounting for nonlinear effects in soft soils). However, the reference velocity used previously was always 500m/s (corresponding to a basin site within a velocity model with a minimum velocity of 500m/s enforced). When rock sites are present, their reference velocities in the LF simulations from the 3D velocity model are usually above 500m/s, hence the use of a constant 500m/s is not necessarily appropriate. Therefore the Vs30ref Vs30ref values that should be used are at the ground surface grid points in the 3D velocity model where the waveforms are output.
...
The default (no arg) behavior is to use Vs30ref from the 3D velocity model.
Therefore the root_defaults.yaml file should look like the following for a 100m grid run, with no lfvsref set:
If you wanted to use To use 500m/s, you must set the lfvsref: 500.0 (or any other constant value) then it must be added under the bb heading in the version's root_defaults.yaml file.
e.g. Please only look at the appropriate line, there is guarantee that other parameters are correct.
Example for old implementation, constant Vs30ref = 500.
Example for new implementation. See that lfvsref is no longer an argument so it will use default behavior which is Vs30ref obtained from 3D velocity modelThis would correspond to gmsim_v16.1.1.