The man was collecting building materials when the first floor collapsed underneath him.

这名男子正在捡拾建筑材料时，突然下方一楼开始倒塌。

A female suicide bomber detonated her explosives and a floor collapsed.

一位女性自杀式炸弹袭击者引爆绑在身上的炸药后一层楼发生倒塌。

Survivors describe buildings liquefying as the tremors hit, each floor collapsing onto the next.

幸存者描述说，发生地震时，建筑物就像熔化似的，一层一层往下塌陷。

They were burrowing under the floors of the buildings, undermining the floor so the floor collapsed.

他们在建筑的地板下打洞，破坏地板导致地板塌陷。