SH line-source near-field singularity
= SH line-source near-field singularity
{c}
{title2=$u\sim-F(t)\log r/(2\pi\mu)$}
Integrating the <shear-horizontal wave> equation with force $F(t)\delta^{(2)}(\mathbf x)$ over a shrinking circle gives $2\pi\mu r\partial_ru\to-F(t)$. Thus the local <displacement field> has the displayed logarithmic singularity. This is a fixed-time near-source limit, distinct from the wavefront limit underlying <SH ray-tube amplitude transport>.