The news that a powerful earthquake had struck southern Turkey first reached the eminent geologist in a pre-dawn video call from a phone number he did not recognize.

Barely awake, he answered to find himself face-to-face with a woman and her daughter trapped in the rubble of their collapsed home.

“Professor, please save us,” he recalled the woman saying. But the call cut out and he lost the number in the flood of calls he received that day. He never learned who the woman was or what had happened to her.

“I cried for two hours,” said the geologist, Naci Gorur, a retired professor who has made it his life’s work to warn Turks about the tremendous threat that earthquakes pose to their country and to implore them to prepare.

The woman had called after the first of the two powerful quakes that hit southern Turkey on Feb. 6 of this year, together killing more than 50,000 people in Turkey and 6,000 in neighboring Syria.

They were the deadliest quakes in Turkey’s modern history, and as the scale of the carnage became clear that day, Dr. Gorur lamented that so little had been done to prepare for a disaster that he and other scientists had long warned about.

“As geologists, we grew tired of saying and writing that this earthquake was coming,” he wrote. “No one reacted.”

Dr. Gorur’s response to the quakes was the most recent chapter in his personal, yearslong earthquake awareness campaign, which has earned him celebrity status in Turkey.

In a land with multiple active faults and a history of catastrophic quakes, Dr. Gorur has become the most prominent voice sounding the alarm about seismic threats and suggesting how society can mitigate them.

Instead of enjoying a quiet retirement, Dr. Gorur, 76, packs his schedule with earthquake-related meetings with business owners, utility managers and municipal officials. He appears on television so frequently that people recognize him on the street.

He blasts regular updates to his 2.2 million followers on X, formerly known as Twitter, explaining plate tectonics, advising Turks to have their homes inspected and retrofitted if needed, and telling them to press their government to build safer cities. He also issues warnings about faults that he fears could shift soon and set off violent tremors.

Since the February quakes, he has fielded a constant barrage of personal queries by phone, text and social media from Turks asking whether their towns are in danger and if they should relocate.

One recent message came from a student in southern Turkey who was struggling to sleep because he was so terrified that a new quake would topple his building.

Was another big earthquake on the way? the student, Abdulkadir Asana, 20, wrote. Should he abandon his city?

Dr. Gorur read the message aloud in the book-lined office of his Istanbul home and sighed heavily. He receives so many such queries that he struggles to keep up, he said. But he understood why so many strangers reached out.

“Because they are scared,” he said.

It was also because in the search for trustworthy information about earthquakes, many people did not trust the government, Turkey’s universities or its disaster relief organization, he said. So they turned to him, and he tried to help.

“It is to show people a way, so that they don’t die,” he said.

Despite his years of public warnings, he turned grim when asked how much difference his voice has made in increasing Turkey’s earthquake preparedness.

“I don’t think it has had much effect,” he said. “Neither at the level of the public nor at the level of local governments.”

He is particularly worried about Istanbul, Turkey’s largest city and economic engine, whose 16 million inhabitants he fears could face a debilitating quake sometime in the near future.

“Istanbul is not ready at all,” he said, predicting that collapsed buildings would leave tens of thousands of people buried under rubble and clog the city’s narrow roads, hampering rescue work and aid delivery.

“There would be chaos in Istanbul,” he said.

Dr. Gorur was born in the eastern Turkish city of Elazig. His father, a carpenter, died when he was 3 years old. His mother, who did not work outside the home, raised him.

As a child, he worked in the summers, he said, selling peppermint candies at the train station, straightening bent nails for a cobbler and renting comic books to other children.

In high school, he tutored other children. He won a spot in the mining faculty at a prestigious Istanbul university and followed a friend into the geology program. He later earned his doctorate from Imperial College London.

In 1999, he was teaching at Istanbul Technical University when a powerful quake struck Izmit, an industrial city east of Istanbul, killing more than 17,000 people.

In the aftermath, Dr. Gorur called on the government to do more to prepare for such disasters, by thoroughly surveying land before allowing construction and strictly enforcing building codes.

In his academic career, he played a critical role in groundbreaking research about the fault under the Sea of Marmara, on Istanbul’s southern coast, making it easier for seismologists to calculate earthquake probability. That included descending nearly 4,000 feet below sea level in a submersible craft.

“In normal life, I can’t even swim!” he said.

He retired in 2014 but continued to speak out. His daughter set up his Twitter account, expanding his reach.

While he regularly criticizes national and local authorities for not giving greater priority to earthquake safety, he avoids targeting specific individuals. The government’s engagement with him is limited.

But he remains perpetually disappointed by the response his warnings receive, making him a sort of Turkish Cassandra, sounding the alarm about impending doom to people who fail to act.

About 20 years ago, he warned his hometown that it was at risk from a nearby fault, he said. On that and future visits, the community welcomed him as a native son, but largely ignored his advice.

“They clapped for me and hugged me, but never took me seriously,” he said.

Then in 2020 — after many years of his warnings — a 6.7-magnitude quake hit the area, toppling buildings in dozens of towns and killing 41 people.

“When the earthquake took place, they started to believe me,” he said.

On Feb. 3 of this year, he warned on social media about pressure on faults in southern Turkey, near the border with Syria. He shared a map with yellow pins marking areas that could suffer damage in a quake — and was again frustrated by the lack of action.

Three days later, the two powerful quakes struck, heavily damaging some of the towns he had marked — and convincing some followers he could predict the future.

Dr. Gorur bats away any suggestion that he is clairvoyant, and dismisses the view of earthquakes as divine acts that humans can do nothing about.

“People don’t know anything about earthquakes,” he said. “Most of them think earthquakes come from God, it is destiny and you cannot get away from your destiny.”

In fact, he says, science can forecast where threats are increasing, even if it can’t predict exactly when a quake will occur.

“It is not earthquake guessing,” he said. “It is simply, perfectly logical.”

He responds to as many personal queries as he can, but he is often overwhelmed and instead posts advice on social media. He tells people to have their homes checked by reputable engineers and to shore them up or move into stronger buildings if they can.

But more important, he says, is to pressure the government to make quake safety a national priority and build Turkish homes and cities accordingly.

“As a part of society, they have to ask for quake preparedness,” he said.

Such an intense focus on potential catastrophes can be exhausting, he said, and his doctor, his wife and his children (he has an adult son and daughter and three granddaughters) tell him to take it easy.

But he feels obligated to keep speaking.

“I am being tested to raise the earthquake awareness of an entire nation and to save their lives,” he said. “I should not miss that opportunity.”