South Korea’s Lotte World Tower, which was designed to be one of the tallest skyscrapers in the world upon completion, is being threatened by the sudden appearance of sinkholes in the area. The sinkholes, which are destroying streets in the surrounding residential area, come as a nearby lake has also begun to disappear, two problems that could delay construction of the skyscraper indefinitely.

The Lotte World Tower, first unveiled in 1995, is to reach more than 1,800 feet high when it’s finished in 2016 but, as crews get closer to that date, problems complicating the construction are becoming more serious. Multiple sinkholes were reported in the last two months in the Songpa neighborhood, the area in Seoul the Lotte World Tower calls home. One hole, the Associated Press said, is 1,640 feet from the construction site and measured 1.5 feet wide and nearly 8 inches deep.

Images of more serious sinkholes have gained traction on social media with each new discovery.

People in Seoul are alarmed by the increasing number of "sinkholes" appearing on streets http://t.co/mTKGwG0wv5 pic.twitter.com/JgeZ2DHY0q â€” The Korea Times (@koreatimes1) July 21, 2014

Sinkholes appear for a variety of reasons, human fault being one of them. The sudden cracks in the earth happen after years of dissolution just beneath the surface. Often, erosion is hastened by a sudden influx of water or outflow of water, depending on the type of rock underlying the soil in an area. A sinkhole made international headlines earlier this year when it swallowed eight corvettes that, just moments before, were sitting safely inside the National Corvette Museum in Bowling Green, Kentucky.

The questions for Korean officials are complicated by word a small lake not far from the Lotte World Tower site has seen its water level drop from 16.5 feet to 14 feet. Park Chang-khun, a civil engineering professor at Kwandong University, told the AP underground water was pooling in the sixth basement level of the Lotte building, with water displaced from the lake being pointed to as the likeliest suspect. The Lotte Group overseeing the tower’s rise has promised there is no danger, though those assurances have done little to sway public opinion.

“It has not guaranteed safety psychologically,” Park said. “Ordinary people would feel even more nervous when Lotte keeps saying it is safe architecture engineering wise.”

An environmental review aims to find out if the sinkholes and other oddities have in fact been caused by construction on the Lotte World Tower but, with more than half of the 123 stories complete, the undertaking is also being examined with the recent Sewol tragedy in mind. Approximately 300 people, most of them students, were killed in April when a South Korean ferry capsized, which prompted government officials to refocus on safety standards and accident preparedness.

Sinkholes have been a problem for South Korea in the past, with Korean news station Arirang TV reporting in the past five years alone, Seoul has seen 133 sinkholes develop.