(a.) Gradually accelerating the movement.

accelerando aggravation beefing-up blowing up blowup concentration condensation consolidation deepening double time double-quick double-quick time drive enhancement exacerbation exaggeration explosion festination forced march forwarding getaway hastening heating-up heightening hurrying impetus information explosion intensification magnification pickup population explosion quickening redoubling reinforcement speeding speedup step-up strengthening thrust tightening