Remember the 15-storey hotel built in six days? Well, this 12-storey apartment building lying down on the ground is not it. That would have been too perfect.
In fact, this apartment block was not built with pre-fab techniques and it's certainly not Level 9 Earthquake-resistant. It's just your typical brick and cement building.
They first build the block and then started to excavate an underground parking on the front. They placed the soil on the back of the building. When the rains came, the water eroded the slope in the front of the terrain while, at the same time, helped to filter the material on the back into the ground. This caused a 3000-tonne lateral pressure, which was too much for the building's weak pillars to resist. They snapped like chopsticks, and the building fell down like a chopped tree.
Luckily for them, it was too far away from the other buildings to cause a domino effect. [Thanks C Levi!]