unstable

Some officials said the two-storey building caved in because its foundation was unstable.

Rescue operations had been challenging due to the unstable structure of the building.

“We can’t have a stable democracy with an unstable climate, and we can’t have a stable climate unless we have a democracy, And so we have to fight both together.”

It is located on the geologically unstable "Ring of Fire" - so called because of the high number of earthquakes and volcanoes that occur here.

The two-storey building had an unstable foundation and could not support the weight of the construction of two more floors, the disaster mitigation agency said.