EXPLAINER: How is technology aiding Miami rescuers' search?

Search teams have been using drones, sonar, highly sensitive microphones and a range of other new and established technologies to help search for people in the oceanside condominium building near Miami that collapsed into a smoldering pile of rubble.

Will any of it help?

About 160 people were still unaccounted for Friday amid fears that the death toll of at least four could go much higher.

WHAT TECHNOLOGIES HAVE PROVEN USEFUL IN SUCH COLLAPSES?

The most common, time-tested technologies used to try to locate survivors in rubble are acoustic detection and sniffer dogs.

Aerial drones equipped with cameras and other sensors can be useful to get a close look at the collapse, especially in the earliest stages of a search to help rescuers know where it's safe to enter. Data from smartphones and telecommunications carriers can show if a missing person was in the area.

Joana Gaia, a professor of management science and systems at the University of Buffalo, said it's common for search teams to use radar and microwave signals that bounce off objects and can identify people and objects. She said it's similar to the technology in cars that beeps when you're close to hitting something backing up.

That can be more useful than cell phone data, which isn’t as exact, especially when speed is of the essence. In a disaster situation, data is only useful if it can be interpreted quickly.

“Responders are operating on a speed rather than accuracy standpoint,” she said. “They think ‘If I think a body is there I don’t care how accurate the signal is, I’m just going to try to go save the person.’”

WHAT ARE MIAMI RESCUERS USING NOW?

Search and rescue teams worked through the night hoping to detect any sounds coming from survivors.

The crews,...