Which collapse pattern is least likely to contain voids?

• A. Pancake collapse
• B. V-shape collapse
• C. Lean-to collapse
• D. A-frame collapse

Answer: (A)

Understanding how different collapse patterns shape the debris field explains why one pattern is least likely to contain voids. In a pancake collapse, floors drop straight down and stack in near-flat, layered blocks. This creates a dense, compact mass with little space left inside, so large air pockets or voids are unlikely to form. Other patterns, like V-shaped or A-frame/lean-to collapses, tend to leave hollow spaces as the structure buckles, arches, or separates, creating internal cavities that can trap occupants or rescuers. So the pancake collapse best minimizes voids compared to the other patterns.