Typically, you add system flexibilty to reduce strain-based loads and increase stiffness (e.g. add supports) to reduce response due to loads that must satisfy equilibrium - the force-based loads. Since your issue is with the wind & seismic loads, I guess you should be looking at adding supports in the horizontal direction.

This has all been said before. I add it again here to take the opportunity to ask how you established your turbine load limits for those wind and seismic loads.