Scientists at the Collm Observatory at Leipzig University registered an underground movement in the area measuring 1.0 on the Richter Scale, just six minutes before the first call to the emergency services on July 18.
An earthquake can be ruled out, the scientists told Der Spiegel magazine, but they suggested it would be feasible that an old mining tunnel collapsed, causing the landslide.
The area around Nachterstedt, in Saxony-Anhalt, was extensively mined for lignite, or brown coal, during the 19th century, meaning the ground was shot through with hundreds of tunnels.
Surveyors have been pulled back out of the Auf der Halde community, where the ground has sunk by a further 0.4 millimetres and is expected to also collapse.
Preparations are now being made for emergency measures to be taken should the remaining houses also fall into the Concordia Lake, which was created by flooding an old open-pit mine.
Officials say that because the houses contain considerable amounts of heating oil, steps may have to be taken to prevent pollution of the lake. This would consist of dumping chemicals onto any oil slick from planes.
At least €10 million is likely to be paid out to the people of Nachterstedt, as compensation for the fact that they are not able to return to their homes.