Families fled their homes as 25 houses collapsed into a canal as the bank crumbled away in Samut Prakan on Thursday night.
No casualties were reported.
Police were called to the canal-side community in tambon Bang Phli about 9pm.
They saw a row of houses which had fallen into Khlong Bang Hia. Residents had earlier begun fleeing their homes, removing what belongings they could.
Residents said an earth embankment along the canal and a flood embankment along a nearby 400-rai pond began to subside on Monday evening. A subcontractor began to repair the earth embankment.
The subsidence became very severe on Thursday night, residents said. The earth embankment broke and water from the canal flooded into the nearby pond, which was about 100 metres deep.
The canal soon ran dry and the bank began to crumble, pulling down houses built along the canal-side. Twenty-five houses collapsed.
A local official said complaints had earlier been made about soil being dug out of the pond and taken away for sale.
