6.5 Earthquake Strikes Guerrero, Tests Sheinbaum as Mexico City Evacuates

Sirens in the National Palace

The sirens started mid-sentence.

Inside Mexico City’s National Palace on the morning of Jan. 2, President Claudia Sheinbaum paused her first news conference of the year as the seismic alarm wailed over live television. “Uy, está temblando,” she said — “Oh, it’s shaking” — before calmly telling aides and reporters to evacuate.

Across the capital, office workers, hospital staff and families in high-rise apartments did the same, pouring into streets and plazas as the ground began to roll. More than 300 kilometers to the south, near the coastal town of San Marcos, Guerrero, the shaking was far more violent.

Quake hits Pacific coast; deaths and widespread damage in Guerrero

At 7:58 a.m. local time, a magnitude 6.5 earthquake struck off Mexico’s Pacific coast, killing two people, injuring at least two dozen and damaging thousands of structures across Guerrero state. The quake was felt in at least a dozen states and set Mexico City swaying for roughly half a minute, reviving memories of far deadlier disasters in 1985 and 2017.

Seismologists and civil protection officials said the event, while moderate compared with past catastrophes, offered an early test of Sheinbaum’s crisis leadership and underlined a stark divide between heavily protected urban centers like the capital and vulnerable rural communities along the coast.

The quake’s epicenter was located near Rancho Viejo and San Marcos, about 57 to 75 kilometers northeast of Acapulco, at a depth of around 35 kilometers on the boundary where the Cocos tectonic plate dives beneath the North American plate. The U.S. Geological Survey and Mexico’s National Seismological Service measured its magnitude at 6.5.

In the small community of Las Minas, part of San Marcos municipality, the shaking brought down the roof and walls of an adobe house, killing a woman in her 50s identified by local authorities as Felicitas Villalba de León. Guerrero Gov. Evelyn Salgado Pineda confirmed the death and said several other residents in the area suffered injuries.

“The municipality of San Marcos is the most affected,” Salgado said in a briefing, adding that damage had been reported in “at least 24 municipalities” across five regions of the state.

As damage assessments progressed over the following days, Guerrero’s civil protection agency and state officials reported that more than 3,800 structures — including homes, schools, health centers and public buildings — were damaged in those municipalities. San Marcos alone accounted for more than 1,500 affected homes, with hundreds classified as having severe or major damage.

Six schools in San Marcos were identified as having serious structural problems, requiring in-depth evaluation before classes could resume. A hospital in the state capital, Chilpancingo, suffered significant damage in part of its building and transferred some patients as a precaution.

Roads, water systems and services disrupted

Infrastructure also took a hit. Authorities reported landslides and rockfalls along stretches of the federal highway between Acapulco and Pinotepa Nacional, as well as on local roads near the coast and in the mountains.

In Acapulco, one of Mexico’s main beach destinations, damage to the Papagayo I, Papagayo II and Lomas de Chapultepec water systems temporarily cut piped water to large sections of the city.

Despite the disruptions, Salgado stressed that tourist areas remained open. “There are no reports of serious damage in Acapulco’s hotel zone. The city is operating normally,” she said, while acknowledging problems with water distribution and some affected neighborhoods.

Mexico City sways — and holds

In Mexico City, no major collapses were reported, but the quake was strongly felt because of the capital’s location atop the soft sediments of the former Lake Texcoco. Those lakebed clays can amplify seismic waves and prolong shaking — an effect that turned distant earthquakes into disasters in 1985 and 2017.

This time, the early warning system and strengthened building codes appeared to blunt the impact.

Mexico City Mayor Clara Brugada Molina said the city recorded 12 injuries linked to the quake, many from falls or panic during evacuation. A 67-year-old man in the Benito Juárez borough died after apparently suffering a cardiorespiratory event and falling on a stairwell while leaving his apartment building, authorities said.

Brugada reported that two structures were being monitored for possible risk of collapse and that inspection teams had reviewed 34 additional buildings and several houses. Five utility poles and four trees were knocked down, and at least 18 localized power outages were reported across the city.

In the historic center, firefighters extinguished a small fire at an electrical substation on Artículo 123 Street that witnesses described as an explosion linked to a short circuit during the shaking.

“Fortunately, we do not have severe structural damage in the city,” Brugada said. She highlighted that about 98% of the capital’s public loudspeakers successfully broadcast the seismic alarm, giving residents from several to more than 30 seconds of warning before strong shaking arrived.

Federal response and aftershocks

At the federal level, Sheinbaum resumed her news conference after evacuating the National Palace and told reporters that the National Seismological Service had initially estimated the quake’s magnitude at 6.5, with an epicenter near San Marcos. She said she had spoken with Salgado and that, at first review, “hasta ahora parece que no hay daños graves” — so far, there did not appear to be serious damage — while cautioning that assessments were ongoing.

The National Civil Protection Coordination activated the National Emergency Committee, and the Defense Ministry and Navy deployed personnel under Plan DN-III-E and Plan Marina, their standard disaster response protocols. Teams were sent to survey damage, clear blocked roads and provide temporary shelter and supplies.

By midday on Jan. 2, seismologists had recorded more than 500 aftershocks. Within a week, that number had climbed past 1,000, and by mid-January the National Seismological Service reported over 2,100 aftershocks, the strongest with magnitudes around 4.5 to 4.7. No tsunami was generated, and Mexican and international agencies said only minor sea-level variations were possible along the immediate coast.

The Guerrero seismic gap — and what hasn’t changed

The quake struck along a particularly scrutinized section of Mexico’s Pacific margin known as the Guerrero seismic gap — a roughly 200- to 230-kilometer stretch between Acapulco and the Papanoa–Zihuatanejo area that has not experienced a major rupture of the subduction interface in more than a century.

Scientists have long warned that the gap could produce a “great” earthquake, potentially between magnitude 8.1 and 8.4, with serious consequences for Guerrero’s coast and for Mexico City, despite the distance. Researchers also have documented so-called slow slip events and the presence of fluids along the fault, which may release some accumulated strain without generating large, sudden quakes.

Experts quoted by Mexican media said the Jan. 2 earthquake, while located near one edge of the gap, did not significantly reduce the seismic hazard. The National Seismological Service emphasized that a single magnitude 6.5 event is too small to release the energy expected from the entire Guerrero segment.

A stark divide in seismic safety

The contrast between outcomes in Mexico City and San Marcos highlighted persistent inequalities in seismic safety.

In the capital, decades of tightened building codes, mandatory structural design standards and widespread retrofitting of public buildings have reduced the risk of catastrophic collapses, though older and informal structures remain a concern. The development of the Seismic Alert System of Mexico (SASMEX), which uses sensors along the Pacific coast to trigger alarms in the capital and other cities, now routinely gives residents precious seconds to move to safer places.

In much of rural Guerrero, many homes are still built of adobe or unreinforced masonry, often outside formal regulatory oversight. The only fatal structural collapse reported from the epicentral area was in such a dwelling. State authorities said thousands of damaged homes now need repair or reconstruction, raising questions about how and with what materials rebuilding will occur.

Schools and health centers — critical facilities in any disaster — also emerged as vulnerable points. Guerrero’s education officials said hundreds of campuses across dozens of municipalities reported some form of damage, necessitating engineering reviews before students can safely return to classrooms.

What comes next

The economic impact of the quake is expected to be modest at the national level, with international monitoring agencies issuing a low, or “green,” alert for overall losses. Locally, however, the costs of repairing homes, infrastructure and basic services are substantial, particularly for families and municipalities that were still recovering from a Category 5 hurricane that devastated parts of Guerrero’s coast in 2023.

For residents along the Costa Chica and in Mexico City, the Jan. 2 shaking was another reminder that they live in one of the world’s most seismically active regions. For Sheinbaum’s new administration, it was an early, real-time demonstration of how well Mexico’s warning systems, building standards and emergency protocols work — and where they still fall short.

As aftershocks continued to rattle the region in the days after the main quake, many families in San Marcos chose to sleep outdoors, wary of weakened walls and roofs. In Mexico City, people went back to offices that had swayed but stood firm, passing by the loudspeakers that had sounded the alarm that morning.

Seismologists say a much larger quake on the Guerrero gap remains possible. How many people survive that future event, they add, will depend on decisions made now — from enforcing building codes in small coastal towns to reinforcing aging structures in the capital and ensuring that early warning systems reach those living closest to the fault.