50th Anniversary of the Tangshan Earthquake: Five Little-Known Historical Details from Mao Zedong's Approval to Aftershocks 44 Years Later

Exactly 50 years ago, at 3:42 a.m. on July 28, 1976, a 7.8-magnitude earthquake struck Tangshan City in Hebei Province, China, claiming approximately 242,000 lives. That year, Zhou Enlai, Zhu De, and Mao Zedong passed away in succession, followed by a devastating earthquake. As a result, in Chinese collective memory and narratives, it is not merely seen as a natural disaster, but as a fateful historical footnote in a year filled with upheaval and transformation. However, the entanglement of this disaster with politics often obscures many of its details, and its true significance extends far beyond geology—its aftershocks even struck Tangshan again 44 years later—and is deeply embedded in the fabric of Chinese society. Today, China's nationwide 120 emergency medical system was established precisely in the aftermath of the Tangshan earthquake. Half a century has quietly passed. On the 50th anniversary of the Tangshan earthquake, we revisit five little-known details in remembrance.

Detail One: Aftershocks Still Occurred in 2020

On July 12, 2020, a 5.1-magnitude earthquake hit the Guye District of Tangshan, with tremors felt in Beijing and Tianjin. The China Earthquake Networks Center later confirmed this was an aftershock of the 1976 Tangshan earthquake, occurring 44 years after the main shock. That an earthquake’s aftershocks could last nearly half a century almost defies common understanding of seismic activity. For example, in frequently seismic Japan, aftershocks typically decay within days to weeks. Why did Tangshan’s aftershocks last so long?

The answer lies in a frequently overlooked fact: Japan lies on a tectonic plate boundary, whereas the Tangshan earthquake was not a plate boundary event but an intraplate earthquake, occurring on a previously unknown fault within the Eurasian Plate.

Pradeep Talwani, a seismologist at the University of South Carolina, lists Tangshan as a global case study of intraplate earthquakes in his book Intraplate Earthquakes, noting that the driving force comes from the Indian Plate pushing northward into the Eurasian Plate at about 5 cm per year. The stress generated by this collision transmits deep into the continental interior, placing northern China within this far-field stress zone.

Studies show that aftershocks from plate boundary earthquakes decay quickly, usually ending within weeks to months. In contrast, intraplate earthquake aftershocks decay extremely slowly and can last for centuries because the lithosphere within plates is stiffer, and the process of stress release along fault zones is much slower and more prolonged.

In other words, as an intraplate earthquake, the Tangshan event accumulated crustal stress very slowly, with the energy buildup process spanning thousands of years.

Seismologists have a rough empirical rule: aftershock duration is approximately one-tenth of the time it took to accumulate the main shock’s energy. Since the Tangshan earthquake accumulated energy over thousands of years, its aftershock activity could theoretically last over a century.

Besides the 2020 event, there have been 26 aftershocks of magnitude 5 or higher in the Tangshan region over the past 44 years. Experts predict such sporadic aftershocks will continue for a considerable time.

Detail Two: The Top Three Deadliest Historical Earthquakes All Occurred in China

Because Tangshan is not located on a plate boundary and was not considered a high-risk seismic zone, the city had virtually no earthquake-resistant construction concepts before 1976. When the earthquake struck, the epicenter was directly beneath the city at a shallow depth of only 12 km, making it an urban-direct earthquake.

As a result, about 97% of the city’s industrial and civilian buildings were destroyed, and approximately 242,000 people died.

Only two historically recorded earthquakes caused more casualties, and both occurred in China and were also intraplate earthquakes.

The first was the 1556 Shaanxi Huaxian earthquake, with the Ming Shi (History of Ming) recording “over 830,000 officials, soldiers, and civilians crushed to death,” making it the deadliest earthquake in recorded human history, a record still unbroken.

Second was the 1920 Ningxia Haiyuan earthquake, magnitude 8.5, killing about 260,000 people, known as the “Global Great Earthquake.” Third was the 1976 Tangshan earthquake.

The 1960 Chile earthquake, at magnitude 9.5, was the strongest ever recorded, yet caused only about 6,000 deaths.

The key difference lies in the fact that the three deadliest earthquakes in China were all intraplate events, occurring in areas without seismic experience and with dense populations, whereas Chile had higher seismic building standards and a sparser population, resulting in fewer casualties.

In the 21st century, two major earthquakes approached the scale of Tangshan: the 2004 Indian Ocean earthquake, with UN estimates of 229,000 deaths, and the 2010 Haiti earthquake, with 220,000 deaths.

Detail Three: There Was Actually a Forecast

The Tangshan earthquake struck in the early morning, catching sleeping residents off guard, a major factor in the high casualties. However, there was, in fact, a forecast.

According to investigative reporting by China Newsweek and Zhang Qingzhou’s book Tangshan Warning Record, one year before the Tangshan earthquake, a 7.3-magnitude quake hit Haicheng in Liaoning Province, and the China Earthquake Administration successfully issued a short-term forecast, greatly reducing casualties.

This success created a split within the China Earthquake Administration: one faction believed northern China still faced major seismic risks, with danger zones narrowing toward Tangshan and Luancheng; the other believed northern China no longer met the conditions for a major quake, and the latter view prevailed.

But abnormal signals in 1976 grew increasingly intense. In June, the State Seismological Bureau received 15 forecast reports—normally only 3 to 5 per month. By mid-July, the Beijing Earthquake Team reported the “seven clearest anomalies since the team’s founding,” Tangshan’s grassroots monitoring points detected abnormal radon levels in water, the temperature of Lengkou hot springs rose by 2°C, and rats emerged from their burrows in large numbers.

On July 14, two weeks before the Tangshan earthquake, the National Earthquake Mass Monitoring and Prevention Experience Exchange Conference was even specially held in Tangshan.

Wang Chengmin, head of the Beijing-Tianjin group at the Earthquake Bureau, orally warned, “Between July 22 and August 5, a magnitude 5 or higher earthquake may occur in the Tangshan-Luancheng area.” He later admitted this was a “rule-breaking act.” On the morning of July 27, Wang finally got to report to Deputy Director Zha Zhiyuan, who decided, “We’ll hold a meeting next week to discuss it.” At that moment, only 15 hours remained before the earthquake.

However, Wang Chunqing, head of the Qinglong County Science and Technology Commission in Hebei Province, heard this information at the July 14 meeting and immediately returned to report. County Party Secretary Ran Guangqi, combining it with local monitoring data, issued an emergency warning on July 25, bypassing the hierarchy. Store doors and windows were opened to prevent collapse injuries, and residents evacuated their homes.

Three days later, the earthquake struck. All 470,000 residents of Qinglong County survived without a single fatality. In 1995, the United Nations sent a delegation to verify the event, and in 1996, Ran Guangqi was awarded a commemorative medal.

Detail Four: The Last Document Mao Zedong Approved

After the earthquake, multiple countries and international organizations, including the United Nations, the UK, Japan, and the US, offered aid, all of which were politely declined. The Chinese government announced it would “decline external assistance.”

In 1976, China was at the tail end of the political campaign “Criticize Deng, Counter the Rightist Reversal Wind,” and Mao Zedong, aged 83, was seriously ill.

On the morning of the earthquake, buildings in Zhongnanhai also shook. According to The Biography of Mao Zedong, edited by the Central Party Literature Research Office, the last document Mao Zedong approved in his lifetime was the “Notification on Earthquake Relief in the Tangshan-Fengnan Area.” Over a month later, on September 9, Mao Zedong passed away.

The death toll was also announced after a long delay. The figure of 242,000 was not officially released by the State Seismological Bureau until November 1977, more than a year after the quake. Prior to that, overseas media had speculated “700,000.”

32 years later, in 2008, the Wenchuan earthquake occurred, and this time China accepted international aid. Rescue teams from Japan, Russia, Singapore, and South Korea successively entered the disaster zone. On September 25, 2008, the death toll of 69,227 and 17,923 missing persons was announced—over four months after the quake.

However, controversially, the Wenchuan death toll has not been updated since, and the 17,923 missing persons have not been counted as “presumed dead” in official statistics. Currently, the official figure for Wenchuan earthquake deaths remains at the September 2008 announcement.

Detail Five: Emergency Numbers Evolved from 555678 to 120

In 1976, Tangshan’s local medical emergency system was extremely weak, with no modern “unified emergency number” or radio dispatch system. After the quake, local medical facilities were almost entirely destroyed, and phones, roads, and hospitals collapsed simultaneously.

Post-quake emergency response had to rely on Beijing and Tianjin. Even the capital, Beijing, had only one emergency number: 555678. Behind it were a dozen or so old ambulances, with no radio dispatch. According to reports, 37-year-old emergency doctor Li Zonghao was the night shift supervisor, and calls flooded in, overwhelming the system.

Li was later sent to the front lines in Tangshan to conduct “triage.” He later recalled to Chinese media that the Tangshan earthquake caused over 3,000 paraplegia cases, many of which were not directly caused by the quake but by improper rescue efforts—well-meaning but medically untrained individuals “dragged” victims from rubble, and during transport, constant jolting turned preventable spinal injuries into permanent paralysis.

The Tangshan earthquake exposed massive institutional gaps. Local rescue and emergency systems were inadequate, and the national rescue system lacked unified coordination, leading to unnecessary losses in patient transport and treatment.