**Questions?**: Clarification on Which Component the Source Term Is Applied to in specfem2D

[Haiqing-Fang]

Dear Team,

I would like to confirm how the source term is applied in the current configuration of specfem2D, specifically for a PSV problem.

We are using source_type = 1 (elastic force or acoustic pressure), and the parameter anglesource is set to 0.0.
In this case, I would like to know:

• Is the force applied to the Vx or Vz component during the update step?
• In the case of an SH problem, would the source be applied to the Ux or Uz component instead?
• Does anglesource = 0.0 correspond to a force in the x-direction?

Thank you very much for your help in clarifying this.

Best regards,