Experts are warning of possible landslides and subsidence in parts of Chiang Dao district in Chiang Mai, as the ground in the area is saturated with water after two months of floods.
The alarm was sounded after a video uploaded to TikTok by @j_khamsan on Monday showed water welling up from the ground at several locations in tambon Muang Na, rendering some roads in the area impassable.
According to Kritsada Moonpa, a geologist at Chiang Mai University's Faculty of Science, the ground in many parts of Chiang Dao district is made out of limestone, which dissolves when exposed to water for an extended period of time.
When the floods hit the North two months ago, vast tracts of land in the area were submerged under water, which dissolved a lot of limestone in the ground and formed large caves filled with rainwater, he said.
When these caves filled up, excess water would seep through any openings in the ground.
As there is a layer of impermeable rock underneath the limestone-rich ground, the excess water often has no other way to go, dissolving even more limestone in the ground and raising the risk of land subsidence, he said.
At this stage, it is unclear how large these underground cavities are, so more exploration is needed, the geologist said.
He expressed concern as many structures in the district are at risk of collapsing due to land subsidence.
