Photo: CCTV News

The recent land subsidence in North China's Tianjin, which led to the evacuation of more than 3,000 residents from nearby high-rise buildings, was identified as a sudden geological disaster possibly caused by underground cavities below a depth of 1,300 meters, said geological experts on Thursday.

On May 31, multiple cracks as wide as a fist appeared on roads near a residential complex in Tianjin's Jinnan district. Some underground parking lots have experienced wall cracks and water seepage. Nearby residents were promptly relocated overnight to ensure their safety. As of June 3, a total of 3,899 residents from at least three 25-floor high-rise buildings were evacuated to nearby hotels, according to the district government.

Tianjin has invited over 20 experts from the Ministry of Natural Resources, the Ministry of Housing and Urban-Rural Development, and the Ministry of Emergency Management, as well as more than 10 professional teams from Beijing, Shanghai, Hebei, and local survey, mapping, monitoring, housing appraisal, and architectural design institutions to carry out on-site monitoring work.

Experts said that the possibility cannot be ruled out that the drilling activities of geothermal wells may have encountered deep geological structures, resulting in shallow soil erosion and subsequent phenomena such as ground subsidence in the affected area.

They further mentioned that from May 31st to June 2nd, the initial development of ground subsidence was rapid, with varying degrees of impact on high-rise buildings along the street. By implementing a series of measures such as grouting, the subsidence of the ground and buildings has significantly slowed down.

The experts emphasized the need to strengthen monitoring of the ground and buildings to prevent secondary disasters and conduct further investigation and assessment of the deep geological structures of the strata.

Global Times