Question is, where the fuck is all that mass going??
Johannesburg has sink holes from old mining shafts that are under the city, but Bangkok?
Discussion
Some places, could be underground salt deposits with new water flows causing salt to dissolve. I think in Bangkok case more likely unconsolidated rocks like loose sands underneath. Put foundations down, dig holes, change underground water flows, mobilise sand grains, erosion. Water flows underground and depending on permeability and grain pore throat size, those flows can carry sediment
Straight to hell!!
Looks like a game glitching at first lol