Kris Vanneste @ on
Auto-discretization in Strata: does it work correctly?
We have experimented with Strata to determine the transfer function at a site in Belgium using equivalent-linear modeling. We have compared the result with two similar tools: EERA and DEEPSOIL.
In Strata (version 3.69), we used a wavelength fraction of 0.2 and a maximum frequency of 25 Hz. Varying the wavelength fraction within the allowed bounds (0.1 – 0.35) did not change the result noticeably. The result was also very similar to that obtained with DEEPSOIL (which has no settings at all to control layer discretization). In EERA (an Excel implementation of SHAKE91), layer discretization has to be specified manually for each layer. If we subdivide the layers in a way that should be comparable to the parameters we used in Strata, we obtain different results. However, changing the subdivision of layers in EERA results in significant changes, with peaks shifting to lower frequencies as subdivision increases and vice versa. So far, we assumed EERA was wrong, and Strata and DEEPSOIL are right.
We noticed that in version 3.81 of Strata, there is an option to disable auto-discretization. So, we are wondering if there was a problem with this feature after all?
Thanks for your time, Kris Vanneste