M7.7 earthquake damages buildings and roads across central Panama

What happened

The shaking lasted about a minute, according to AFP, and was felt across the country of about 4.5 million people. The USGS first estimated the magnitude at 8.0 and then revised it to 7.7. Health Minister Fernando Boyd named Herrera, Cocle and Los Santos as the most affected provinces, and the news site Colombia One added Veraguas. President Jose Raul Mulino called it a major disaster and travelled to Penonome to lead the response.

Damage was widespread. In Penonome, a church and a hotel were badly damaged. President Mulino said some roads had completely collapsed. The town of Tonosi, in Los Santos, could be reached only by air. Colombia One reported structural damage at seven schools, which must be inspected before they reopen, partial collapses at some hotels in Playa Blanca, and more than 100 damaged homes in the historic district of Panama City. A drinking water plant in Chitre was running at only 20 percent of capacity.

Other systems held up. The Panama Canal Authority said ships kept moving normally. The international airport at Tocumen closed for inspections and then resumed flights. A canal bridge shook strongly but stayed standing, and people evacuated tall buildings in Panama City. Classes were suspended nationwide. The local geosciences institute recorded more than 80 aftershocks in the first hours, one above magnitude 6, and Colombia One later reported more than 100.

Help began to arrive quickly. The United States said it was sending a 22-member urban search and rescue team that included structural engineers. The Development Bank of Latin America and the Caribbean announced an immediate donation of 250,000 US dollars and a financing facility of up to 50 million dollars. AFP noted that large earthquakes are rare in central Panama, as most occur in the western province of Chiriqui.

The engineering behind it

The USGS data explain why damage was severe. Its ShakeMap estimated a maximum intensity of about IX on the Modified Mercalli scale, which means violent shaking. The highest estimated ground acceleration was about 0.77 times the acceleration of gravity. The USGS says the focal mechanism shows left-lateral strike-slip faulting, in which the two sides of a fault slide past each other horizontally. Shallow earthquakes like this one release their energy close to the surface, so shaking near the epicentre is strong.

The USGS also runs a system called PAGER, which estimates likely losses within hours. For this earthquake, it gave a yellow alert for deaths and a red alert, its highest level, for economic losses. Its ground-failure model gave a red alert for landslides and an orange alert for liquefaction. These are model estimates, not counts, but they help governments and aid groups judge the scale of a disaster before full reports arrive.

The pattern of damage matches what engineers often see. Older buildings of unreinforced masonry, such as many churches and historic houses, are heavy and brittle. Their walls crack and fall when shaken sideways, because they have no steel to hold them together. Structures designed to modern seismic codes, with ductile reinforced concrete or steel frames, can bend and absorb energy without collapsing. This is a general engineering observation; the sources do not yet give the age or design of each damaged building.

Aftershocks add to the risk. The USGS has published an aftershock forecast for this sequence that runs for a full year, to October 2027. A building that survived the main shock with cracked walls or damaged joints may be much weaker than before, and a later aftershock above magnitude 6 can bring it down. This is why engineers inspect and mark damaged buildings before people return, and why temporary shoring is often placed under damaged walls and floors.

What it means in Nepal

Nepal knows this kind of event. According to the USGS, the earthquake of 25 April 2015 near Bharatpur was magnitude 7.8 at a depth of about 8 km, similar in size and depth to the Panama quake. The sources for the Panama story do not compare the two, and building types differ between the countries. But the engineering questions are the same: which buildings fail, why they fail, and how to design and strengthen them so they do not.

The Panama reports also show the idea of lifeline infrastructure. A damaged water plant, a cut road and closed schools can stretch a disaster out for weeks after the shaking stops. The town of Tonosi, reachable only by air, shows how one road failure can isolate a whole community. Designing roads, bridges, water systems and schools to keep working after an earthquake is a large part of reducing harm.

The US team that included structural engineers points to a third lesson. After a large earthquake, engineers inspect buildings quickly to decide which are safe to enter, which need repair and which must be closed. Colombia One reported that Panama's seven damaged schools must be inspected before they reopen. Findings from such inspections later feed into research and building codes. That reconnaissance work needs a clear understanding of how structures behave and fail, and calm judgement under pressure.