NASA's heartbeat detector FINDER helps in disaster relief after Mexico's 7.1-magnitude earthquake

A suitcase-sized NASA radar instrument, that can detect heartbeats, is helping disaster relief workers save lives of people trapped under rubble after a 7.1 earthquake stunned central Mexico, killing at least 139 people as buildings collapsed in plumes of dust. Thousands fled into the streets in panic, and many stayed to help rescue those trapped.

The technology called Finding Individuals for Disaster and Emergency Response (FINDER) was developed by NASA’s Jet Propulsion Laboratory (JPL) and the Department of Homeland Security’s Science and Technology Directorate in the US.

“Our hearts go out to the people of Mexico. We are glad to know our technology is being used to make a difference there,” said Neil Chamberlain, task manager for FINDER at JPL.

FINDER sends a low-powered microwave signal—about one-thousandth of a cell phone’s output—through rubble. It looks for changes in the reflections of those signals coming back from tiny motions caused by victims’ breathing and heartbeats.

In tests, FINDER has detected heartbeats through 30 feet of rubble or 20 feet of solid concrete.

It was also used in Puerto Rico last week to search for survivors of Hurricane Maria. While radar can not search through water, it is useful for detecting heartbeats through rooftops. People trapped in flooded buildings often run to the upper floors.

The technology evolved from JPL’s efforts to develop low-cost, small spacecraft radios, using signal processing developed to measure small changes in spacecraft motion.

FINDER is used alongside a variety of other techniques, including trained dogs, acoustic sensing devices and thermal imagers. All these techniques are usually deployed together.

When FINDER was deployed to Nepal after a major earthquake in 2015, it helped find four men trapped under a collapsed textile factory.

Scores of buildings collapsed into mounds of rubble or were severely damaged in in densely populated parts of Mexico City and nearby states. Mayor Miguel Angel Mancera said buildings collapsed at 44 places in the capital alone.

The quake is the deadliest in Mexico since a 1985 quake on the same date killed thousands. It came less than two weeks after another powerful quake left 90 dead in the country’s south.

Mancera said at least 30 had died in Mexico City, and officials in Morelos, just to the south, said 54 had died there.

At least 26 others died in Puebla state, according to state disaster prevention chief Carlos Valdes.

Governor Alfredo del Mazo said at least nine had died in the State of Mexico, which also borders the capital.

Mancera said that 50 to 60 people were rescued alive by citizens and emergency workers.

At one site, reporters saw onlookers cheer as a woman was pulled from the rubble. Rescuers immediately called for silence so that they could listen for others who might be trapped.

Mariana Morales, a 26-year-old nutritionist, 26, was one many who spontaneously participated in rescue efforts.  She wore a paper face mask and her hands were still dusty from having joined a rescue brigade to clear rubble from a building that fell in a cloud of dust before her eyes, about 15 minutes after the quake.

Morales said she was in a taxi when the quake struck, and she out and sat on a sidewalk to try to recover from the scare. Then, just a few yards away, the three-story building collapsed.

A dust-covered Carlos Mendoza, 30, said that he and other volunteers had been able to pull two people alive from the ruins of a collapsed apartment building three hours of effort.

“We saw this and came to help,” he said. “It’s ugly, very ugly.”

Alma Gonzalez was in her fourth-floor apartment in the Roma neighbourhood when the quake collapsed the ground floor of her building, leaving her no way out, until neighbours set up a ladder on their roof and helped her slide out a side window.

Gala Dluzhynska was taking a class with 11 other women on the second floor of a building on the trendy Alvaro Obregon street when the quake struck and window and ceiling panels fell as the building began to tear apart.

She said she fell in the stairs and people began to walk over her, before someone finally pulled her up.

“There were no stairs anymore. There were rocks,” she said.

They reached the bottom only to find it barred. A security guard finally came and unlocked it.

The quake caused buildings to sway sickeningly in Mexico City and sent people throughout the city fleeing from homes and offices, and many people remained in the streets for hours, fearful of returning to the structures.

Alarms blared and traffic stopped around the Angel of Independence monument on the iconic Reforma Avenue.

Electricity and cell phone service was interrupted in many areas and traffic was snarled as signal lights went dark.

The US Geological Survey said the magnitude 7.1 hit at 1:14 pm (2:15 p.m. EDT) and it was centred near the Puebla state town of Raboso, about 123 kilometres southeast of Mexico City.

Puebla Governor Tony Gali tweeted that there had been damaged buildings in the city of Cholula including collapsed church steeples.

Earlier in the day workplaces across the city held readiness drills on the anniversary of the 1985 quake, a magnitude 8.0 shake, which killed thousands of people and devastated large parts of Mexico City.