Finite-time singularity via multi-layer degenerate pendula for the 2D Boussinesq equation with uniform C^{1,frac{4{3}}-1-ε}cap L^2 force

We establish the existence of compactly supported solutions of the inviscid incompressible 2D Boussinesq equation with C^{1,frac{4{3}}-1-varepsilon}cap L^{2} force that develop a singularity in finite time. Importantly, the force preserves this regularity at the blow-up time. Moreover, the forces in the vorticity and density equations have compact support. The mechanism behind the blow-up is an accumulated hysteresis effect on the vorticity caused by an infinite chain of "degenerate" pendula and flickering density.