Video of the recent collapse at the Arecibo Observatory, taken from two different perspectives, show the dramatic moment when a main cable failed, causing the 740 tonne instrument platform to fall onto the large radio dish below.
The first of the two videos was taken from the Arecibo Observatory control room, where radio astronomers normally do their work. The camera was recently installed in this location to capture a collapse should it happen, Ashley Zauderer, program director for Arecibo Observatory at the National Science Foundation, told reporters today.
As the video shows, the platform did not fall straight down. It was more of a swinging action, as a main cable snapped from one of the three support towers. The video also shows the tops of the towers breaking off, some of which measure over 18.29 m in length, according to John Abruzzo, managing principal of Thornton Tomasetti, an engineering firm brought in to assess the situation following the recent failure of two cables at the famous facility.
The collapse involved some “very violent and unpredicted behaviour,” said Zauderer.
The second video is just as remarkable, as it was captured by an aerial drone. It just so happened that the drone was being used to inspect the top of Tower 4 when one of three remaining main cables snapped. Looking at the video, you can see three cables running parallel to one another. A fourth cable should’ve been there, but it failed earlier this month (you can actually see the frayed remains of the cable at top). Each cable consists of 170 wires, said Abruzzo. The middle of the three remaining cables is the one that failed, triggering a reaction that caused the entire structure to collapse. A fourth cable located above the trio is used to support the catwalk, and is not a main cable.
Incredibly, the drone operator was able to turn the camera around to capture an aerial view of the carnage below. In the distance, the top of tower 12 can be seen collapsing.
No one was hurt during this catastrophic failure, the exact cause of which is still being determined. Zauderer said all dangerous debris fell within previously designated restricted zones.
On a positive note, the nearby visitor’s centre did not sustain any serious damage. From here, the priority continues to be safety, mitigating environmental issues, and finding ways to support the staff at the facility and the people of Puerto Rico, said Zauderer. Built in 1963, the radio dish was recently slated for demolition, as repairs were deemed too dangerous.