In the aftermath of the 8.3-magnitude earthquake that shook Chile Wednesday night, many Facebook users utilized “Safety Check,” a feature on the social media website used to give updates to friends during a disaster.
Facebook users with friends in the quake-prone nation –including residents of the Chilean capital, Santiago – were prompted to access Safety Check when they logged on. The feature displayed a list of Facebook friends near the disaster, divided into three categories: all friends in area, friends marked safe and friends not marked yet.
As each friend in the impacted area marked themselves “safe,” users connected to them were sent notifications. Friends could also mark others “safe,” in case that person was unable to access the social media website following the earthquake.
The social media website describes the safety feature as a way to “connect with friends and loved ones during a disaster” and adds, “If you're near a natural disaster, you can tell friends if you're safe and check to see if they're safe, too.”
According to this post from Facebook co-founder Mark Zuckerberg, Safety Check first launched in October 2014. Facebook previously used the Safety Check feature in late April 2015 to connect survivors of the deadly Nepal earthquake with their loved ones.
“Over the last few years there have been many disasters and crises where people have turned to the Internet for help. Each time, we see people use Facebook to check on their loved ones and see if they're safe. Connecting with people is always valuable, but these are the moments when it matters most,” Zuckerberg wrote.
Zuckerberg said the feature was inspired by the devastating, 9.0-magnitude earthquake and tsunami that hit Japan in March 2011.
The U.S. Geological Survey reported the epicenter of Wednesday’s earthquake was approximately 29 miles west of Illapel, a town of about 35,000 residents approximately 175 miles north of Santiago.
The massive quake forced more than 1 million residents to evacuate. Homes and businesses were damaged and rumbles were felt across the country and in other parts of South America.
At last count Friday morning, 12 people had been killed by the natural disaster. Chilean leaders said the death toll could rise as emergency crews are able to access the areas hardest hit by the earthquake.
In its wake, several coastal towns were flooded from small tsunami waves set off by the quake. Authorities issued a tsunami warning for the Andean nation's entire Pacific coast as residents sought safety on higher ground and inland regions. Those tsunami warnings were lifted Thursday.
Tsunami advisories were also in effect for Hawaii and parts of California following the quake.
The earthquake lasted for three minutes and caused buildings to sway in Santiago. Dozens of aftershocks then continued to jolt the country.
The natural disaster was the strongest tremor since the 8.8-magnitude earthquake and tsunami in 2010 that killed hundreds and caused heavy damage to the nation.
Santiago resident Carolina Barros Urzua had just gotten home from the Santiago Metro railway when the earthquake struck.
She said the three-minute duration of the earthquake was by far the worst part, and the abrupt shaking felt like it lasted an eternity.
“The sensation was horrible because the movement would not stop,” Barros Urzua told NBC 7 San Diego. “It was horrible. Thank goodness it’s over.”
Barros Urzua said many Santiago residents felt the quake was less intense than the deadly 2010 tremor.
This time around, electricity in the capital did not cut out, she said, though patchy service to landlines, cell phones and the Internet made communicating with loved ones difficult.
Barros Urzua was among the many Facebook users who marked herself “safe” on Safety Check.
Santiago resident Francisca Saavedra told NBC 7 the aftershocks were as frightening as the earthquake because they were very strong and consistent.
“The earthquake wasn’t very loud, but there was so much shaking,” Saavedra explained.
She said the tsunami warnings added to the concern and anxiety felt by many across the city.
Meanwhile, Santiago resident and mother of two Danisa Lonza Robledo also told NBC 7 the quake wasn’t as strong as the 2010 tremor, but very scary nonetheless.
“During the 2010 earthquake it really felt as if everything was going to fall,” Lonza Robledo explained. “This one was strong – but not as strong. Perhaps Chileans are just accustomed to big earthquakes by now.”
Lonza Robledo said she and her family were on the third-story of a residential building when the tremor hit.
"When we realized that it was getting stronger and not stopping, we went downstairs and went outside to the streets. We heard the windows on our building rattling, alarms sounding off and trees swaying violently back and forth. Everything was moving," she described.
Lonza Robledo said she tried to open a gate near her building, but couldn't immediately open it due to the constant motion moving the ground and objects all around her.
After a few minutes, she said the shaking began to subside. Then, she heard the sirens of ambulances rushing throughout her neighborhood.
Soon thereafter, the aftershocks rolled in.
Accustomed to the aftershocks, Lonza Robledo said she and her husband and children slept through most of them Wednesday night.
She said what kept her up and worried was her brother, who was near a community under a tsunami warning. Fortunately, he eventually got in touch with her to report that he was fine.
The earthquake came just two days before Sept. 18 – Chile’s Independence Day – a very significant and widely-celebrated holiday in the country.
Schools and businesses are closed throughout the nation for Sept. 18 each year, and Barros Urzua said many Chileans had traveled to coastal cities to celebrate the long holiday weekend.
“Many of these people planned to set up booths along the coast this weekend during the festivities,” she explained. “All of them were impacted.”
According to the U.S. Geological Survey, the earthquake occurred as the result of “thrust faulting on the interface between the Nazca and South America plates in Central Chile.”
The Nazca tectonic plate, which plunges beneath the South American plate and pushes the towering Andes cordillera to ever-higher altitudes, makes Chile one of the world’s most quake-prone regions.
The strongest earthquake ever recorded on earth happened in Chile: the infamous 9.5-magnitude quake in 1960 that killed more than 5,000 people.