Before the park was built, it was a residential area, in which there were many manually excavated wells. When building the park, these wells will be buried. After a period of time after construction, there is a collapse situation, which seriously threatens the safety of people's lives and property. It is necessary to concrete the known collapse wells and detect the location of other hidden wells contained in the area.

Field map

From the above inversion contour map, it can be seen that there is an anomaly in the near-sighted resistivity contour map attached at a known location of 32 meters, which is consistent with the location recorded on site. It is speculated that there is a suspected area around 12, 24 and 94 meters, which was later verified to be consistent by drilling.