Earthquakes and tsunamis in Peru: understanding and preparing

Why the ground shakes in Peru

The Earth’s surface is broken up into large rigid plates, the tectonic plates, which move a few centimetres a year. Off Peru, the Nazca plate, which carries the floor of the Pacific Ocean, moves east and meets the South American plate, which carries the continent. Being denser, it sinks beneath it: this is subduction. According to the Geophysical Institute of Peru (IGP), the two plates converge at an average rate of 7 to 8 centimetres a year (IGP report on the Pisco earthquake), without interruption for millions of years.

The plates do not slide smoothly. Where they touch, they stay locked for years or centuries, the rock deforms and stores energy, then gives way all at once: that is an earthquake. The same push deforms the edge of the continent: it is linked to the formation of the Andes, and it still moves faults in the Andean crust. Peru is part of the Pacific Ring of Fire, the ring of subduction zones around that ocean: according to the IGP, more than 80% of the world’s earthquakes are concentrated around the Pacific plate (IGP, September 2026).

Three families of earthquakes

The IGP distinguishes three main origins, which differ in both depth and effects.

Where the two plates meet. These are interface earthquakes, under the sea and under the coast, down to about 60 kilometres deep. They are the most frequent and can be the most powerful: the Pisco earthquake of 2007 began some forty kilometres down, off the coast. They are also the ones that can lift the seabed and trigger a tsunami.

Within the sinking plate. Beneath the continent, the Nazca plate keeps going down and deforms internally: these are intraplate earthquakes, or intermediate-depth earthquakes. The IGP places them down to 150 kilometres deep in the north and centre of the country, and down to 300 kilometres in the south. The magnitude 7.0 earthquake of 20 August 2026, in the Ayacucho region, is an example: its focus lay 108 kilometres underground (IGP). Less often, very deep earthquakes, between 500 and 700 kilometres, occur near the borders with Brazil and Bolivia.

In the crust of the Andes. The push of the plates also moves faults in the continental crust. These crustal earthquakes are usually shallow, less than 15 kilometres deep according to the IGP. Among the known faults, the institute mentions Tambomachay near Cusco, Huambo-Cabanaconde and Ichupampa in the Arequipa region, Huaytapallana and Altos del Mantaro in the Junín region, and the Cordillera Blanca in Áncash. The Chupaca (Junín) earthquake of 18 July 2026 was of this type: magnitude 5.4, only 9.5 kilometres deep.

Why depth changes everything

The deeper the focus, the further the waves travel before reaching the surface: they weaken, but spread over a larger area. A deep earthquake is therefore often felt very far away, with more moderate shaking directly above it. The 2026 Ayacucho earthquake was felt within a radius of about 450 kilometres, but the IGP recorded no damage or significant effects more than 200 kilometres from the epicentre. Conversely, a crustal earthquake of moderate magnitude can be violent over a small area, right above it.

As the IGP sums it up, distance and depth generally soften the shaking, but it is depth, the type of ground and the quality of buildings that ultimately decide how much damage is done.

Words and measurements

Sismo, temblor, terremoto

In English, earthquake, quake and tremor are used fairly loosely. In Peru, institutions use sismo in their reports. In conversation you mostly hear temblor, and terremoto for a violent, destructive earthquake. The dictionary of the Royal Spanish Academy treats them as synonyms, noting only that terremoto suggests a violent shock and temblor one of low intensity, or any earthquake in Latin America. No official magnitude marks the switch from one word to another: it is a matter of usage, not a scale.

Focus, epicentre, depth, aftershocks

The focus (or hypocentre) is the point underground where the rupture begins. The epicentre is the point on the surface directly above it. The depth is the distance between the two. For a large earthquake, that point is only the start: the rupture then spreads along a fault that can be more than a hundred kilometres long.

Aftershocks are the smaller earthquakes that follow a major one, in the same area, for days, weeks or longer. After the Pisco earthquake, the IGP recorded several hundred in the following days. They are not harmless: in Chupaca in 2026, a magnitude 5.0 aftershock brought down houses already damaged by the main earthquake.

Magnitude and intensity

These are two different measurements, often confused.

The moment magnitude, written Mw, is now the reference measurement for most earthquakes: it is based on the physical properties of the rupture (fault area, slip, rock stiffness). The Richter scale, created in 1935 for Californian earthquakes, popularised the idea of magnitude, but it is hardly used any more (USGS). The two do not always give the same figure: for the Pisco earthquake, the IGP calculated a local magnitude of 7.0 “on the Richter scale” and a moment magnitude of 7.9. The second describes an earthquake of that size better.

Two agencies can also publish slightly different values for the same earthquake: 7.9 for the IGP, 8.0 for the United States Geological Survey (USGS), again for Pisco. It is not a mistake, but two calculations from different data.

A scale that climbs fast

Magnitude is logarithmic. According to the USGS, each whole step corresponds to a ten times larger amplitude on a seismogram, the recording of the vibrations, and to about 32 times more energy released. A magnitude 8 earthquake therefore releases about a thousand times more energy (32 × 32) than a magnitude 6 one. That is why a magnitude “just a little higher” changes everything.

Three things should nevertheless be kept apart: the energy released at the source, the amplitude measured by an instrument in one place, and the damage, which depends on everything else. None of the three can simply be deduced from the other two.

Two earthquakes of the same magnitude, two different stories

Peru offers a striking example. On 15 August 2007, the Pisco earthquake, magnitude 8.0 according to the USGS, struck some forty kilometres deep, close to the coast; the USGS counts at least 514 dead and more than 39,700 buildings damaged or destroyed. On 26 May 2019, another magnitude 8.0 earthquake struck the north of the country, but about 110 kilometres deep, beneath the Amazon rainforest: the USGS reports two deaths, hundreds of damaged homes and two collapsed bridges in the Yurimaguas area. Same magnitude; different depth, distance from towns and buildings.

How many earthquakes? Frequency and comparisons

Recorded, felt, destructive

The number of earthquakes depends on what you count. Instruments record many more than people feel, and only a small share cause damage.

In Peru, the IGP’s National Seismological Centre (CENSIS) publishes a report for every notable earthquake located in the country or off its coast. It published 840 in 2025 and 798 in 2024, most of them between magnitude 3 and 5 according to its monthly bulletins (December 2025 bulletin). That is more than two a day on average. Some occur at sea, and an earthquake of that size is generally felt only near its epicentre.

In Switzerland, the Swiss Seismological Service (SED) records an average of three to five earthquakes a day in Switzerland and neighbouring countries, or 1,000 to 2,000 a year, but people feel only 20 to 30 a year; the SED points out that the number also depends on how dense the network of stations is (SED). So the two figures cannot be compared: Peru counts the earthquakes that are the subject of a report, Switzerland all those its instruments detect, however tiny.

What these figures do not tell you

An annual number of earthquakes for a whole country does not turn into a probability for a traveller. It does not say where, when or how hard the ground will shake during a two-week stay, and a large number of small earthquakes does not bring a big one closer or push it further away. What it does say is that in Peru, feeling a tremor is part of normal life, and that it is worth knowing how to react.

Peru, Chile, Japan and Switzerland

Comparing countries only makes sense on comparable points: where the earthquakes come from, the strongest known, and how each country prepares. A ranking of “safe” and “dangerous” countries would make none.

Preparedness varies as much as geology. Since 1 October 2007, Japan has issued nationwide earthquake early warnings, a few seconds before strong shaking (JMA). Peru is rolling out a system of this kind, still being brought into service in 2026 (see below). In Switzerland, the SED puts the probability of an earthquake of magnitude 6 or more next year at 1%, and points out that no region of the country is free of seismic hazard.

A few earthquakes that help to understand

These four earthquakes do not sum up the country’s history: each shows a different side of the phenomenon. Older magnitudes are estimates made after the event, from contemporary descriptions.

1746. On the evening of 28 October, a very strong earthquake ruins Lima: according to the official report of the time, quoted by the NOAA catalogue, it kills 1,141 people out of about 60,000 inhabitants. About half an hour later, according to the accounts compiled by NOAA, the sea floods Callao: almost the whole population of the port dies, and only about 200 people survive. For the magnitude, the same catalogue lists estimates ranging from 8.0 to 9.2: the gap comes from the methods, since no instruments existed. This earthquake lastingly changed the way Lima was built, with light upper floors of quincha, a frame of wood and reeds covered with mud (see the historic centre).

1970. On 31 May, a magnitude 7.9 earthquake strikes under the sea, a few tens of kilometres deep, off Chimbote. In the Callejón de Huaylas and on the coast, many adobe houses, often built on alluvial ground, collapse. In the Cordillera Blanca, the shaking breaks off part of the north summit of Huascarán: the avalanche of ice, rock and mud buries the town of Yungay. The NOAA catalogue counts 66,794 deaths for the whole event; the USGS study published in 1971 attributes more than 18,000 to the avalanche alone. A secondary effect can therefore, on its own, claim thousands of lives far from the epicentre (see Huaraz).

2001. On 23 June, a magnitude 8.4 earthquake ruptures the plate interface off the south of the country. The shaking damages many historic buildings in Arequipa, and landslides cut roads. On the coast, a local tsunami hits Camaná: the USGS counts at least 74 dead, 26 of them from the wave, and 64 missing in the Camaná and Chala area. According to a reference cited by NOAA, the wave reached the beach resorts of Camaná about a quarter of an hour after the earthquake.

2007. On 15 August, the Pisco earthquake lasts a long time: the IGP measured two successive ruptures, about 70 seconds apart, in a process lasting about 210 seconds in all. In Pisco, about 80% of homes are damaged, above all the adobe and quincha houses and churches. The ground liquefies in places along the coast, and the Pan-American Highway cracks. A tsunami reaches the south of the Paracas peninsula: in the hamlet of Lagunilla, three people who had not moved away from the beach die, although there was high ground less than 100 metres away, according to the observations compiled by NOAA.

Why the effects vary from place to place

In the same earthquake, two nearby places can experience very different shaking. Five factors combine:

• distance from the focus, which generally softens the shaking;
• the depth of the earthquake, as seen above;
• the ground, which may or may not amplify the movement;
• how long the shaking lasts: the longer it goes on, the more likely a fragile building is to give way;
• the building itself: its design, its materials and the quality of its construction.

The ground: amplification, liquefaction, landslides

When the waves pass from rigid rock into softer ground, such as sand, clay or fill, the movement can be amplified: this is local amplification. After the 2026 Chupaca earthquake, the IGP measured ground motion amplified more than two and a half times in some neighbourhoods, with damage concentrated on adobe houses, while nearby villages were barely touched. The head of the institute sums it up: two homes a few metres apart can experience completely different shaking and damage (IGP, August 2026).

Liquefaction mainly affects waterlogged sandy ground: during the shaking it loses its strength and behaves like a liquid for a while, so buildings sink or tilt. It was observed on the coast during the Pisco earthquake. In the mountains, tremors often trigger rockfalls and landslides: after the 2026 Ayacucho earthquake, the IGP recorded many collapses on the slopes around Coracora.

Lima

Lima and Callao face the zone where the plates meet. The Peruvian earthquake-resistant design standard places them in zone 4, the most demanding. The city has had strong earthquakes in the 20th century, notably in 1940, 1966 and 1974, all above magnitude 8 according to the NOAA catalogue. The IGP considers that the contact zone off the central coast has been building up energy since the 1746 earthquake and could produce a high-magnitude earthquake, followed by a tsunami; nobody can say when (IGP, September 2026).

The ground beneath the city is very varied. The Japan-Peru Centre for Earthquake Engineering Research and Disaster Mitigation (CISMID) at the National University of Engineering has mapped, district by district, the types of ground, their amplification factors and the areas that would flood in a tsunami: this is the seismic microzonation of Lima and Callao, carried out with the Ministry of Housing and combined into a single map in 2021 (CISMID).

That is why a neighbourhood cannot be judged by its reputation. The ground can change from one street to the next, and the same street may hold a recent building designed by engineers, an old adobe house and a building extended floor by floor without any study. And a new facade says nothing about the foundations or the steel reinforcement. To choose a neighbourhood on other criteria, see which neighbourhood to choose in Lima.

The coast, the Andes, the Amazon

On the coast, people live closest to the great interface earthquakes, and low-lying stretches of shoreline can be reached by a tsunami. Many towns there are built on alluvial ground and sand, more prone to amplification and liquefaction.

In the Andes, crustal faults and earthquakes in the sinking plate add to this. Adobe, still very widespread, and slopes, where rockfalls start, weigh heavily in the damage. The south also has active volcanoes, such as Misti above Arequipa, which the IGP monitors.

In the Amazon, strong shaking is less frequent, and the standard places, for example, the province of Maynas, which includes Iquitos, in zone 1, the least exposed. But deep earthquakes, like the one in 2019, can be felt strongly there and damage buildings.

None of these regions is “safe” or “dangerous” as a whole: within each, the ground, the slope, the distance to faults and above all the quality of the building make the difference.

Peru’s earthquake-resistant building standards

The National Building Regulations and standard E.030

In Peru, building rules are gathered in the National Building Regulations (Reglamento Nacional de Edificaciones, RNE), approved in 2006 and kept up to date by the Ministry of Housing; SENCICO, the public body for training and standards in the construction sector, publishes the texts. Its standard E.030 “Diseño Sismorresistente” (earthquake-resistant design) applies throughout the country to new buildings, to strengthening existing ones and to repairing those an earthquake has damaged.

This standard has just been amended: Ministerial Resolution 183-2026-VIVIENDA of 28 April 2026 approved a new version, prepared by a working group set up in 2024 and put out to public consultation in 2025 (MVCS). It classifies ground according to new criteria, requires the ground’s own vibration period to be measured for important buildings in zone 4, makes it compulsory to analyse the earthquake acting in two directions at once, revises the rules for buildings with thin reinforced-concrete load-bearing walls, and sets minimum requirements for microzonation studies.

A transitional provision, amended on 2 June 2026 by Resolution 217-2026-VIVIENDA, allows projects already under way on that date (technical file being prepared or approved, building permit applied for or granted, preliminary design submitted) to be completed under the previous text. A building handed over in 2026 or the following years may therefore have been designed under either version: not a defect in itself, but a question worth asking.

The standard divides the country into four seismic zones. Each has a reference ground acceleration, the one with a 10% probability of being exceeded in 50 years on rigid ground: 0.45 times gravity in zone 4, where Lima and Callao lie, and 0.10 in zone 1. It is a probabilistic estimate of ground motion, not a magnitude.

What the standard aims to achieve

The aim is written into article 2: to prevent loss of life, keep basic services running and minimise damage to property. In practice, the standard requires that:

• in shaking that is severe for the location, the structure does not collapse or seriously harm people, even if it suffers significant damage;
• in moderate shaking, it holds up with repairable damage;
• essential buildings, such as hospitals, remain operational after a severe earthquake; new hospitals in zones 3 and 4 must indeed rest on seismic isolators, bearings that decouple the building from the ground.

“Earthquake-resistant” therefore does not mean “undamaged”. The standard accepts that a building may be damaged by a severe earthquake, provided it does not collapse on its occupants. And it does not reason in magnitudes: a building is designed for the ground motion expected at its location, according to the zone, the ground and its use, not to “withstand a magnitude 8 earthquake”.

Three links matter equally: the ground survey, which sets the site parameters; the structural design, which the standard wants simple, symmetrical, continuous and able to deform without breaking; and the construction, which the standard explicitly ties to good building practice and rigorous structural supervision. A fine design badly built offers no protection.

A standard is not a guarantee

The existence of a standard says nothing about whether a particular building complies. According to the National Housing and Urban Planning Policy adopted in 2021, nearly 70% of the country’s homes were built without technical assistance (Andina). Many houses grow floor by floor, as the family’s means allow.

Neither age, nor price, nor neighbourhood, nor a new look is enough to judge. An old building may have been well designed and strengthened; a recent one may have been built without checks. Some defects can be seen, though: a floor clearly added later, a very open ground floor (garage, shop) under floors full of walls, what the standard calls a “soft storey” (piso blando), or cracks in columns and beams.

Questions to ask about a home

For a few nights in a hotel, it is enough to locate the exits and the safe zone on your floor. For a long let, a purchase or building work, a few questions are reasonable:

• Does the building have a building permit (licencia de edificación) and a completion certificate from the municipality?
• In what year was it designed, and under which version of the standard?
• Was a ground survey carried out, and by whom?
• Are the structural drawings signed by a civil engineer? Can you get a copy?
• Were floors added after the original construction, and under what permit?
• Where are the exits, the stairs, the safe zone and the assembly point?

Call in an independent civil engineer, registered with the Colegio de Ingenieros del Perú (CIP), before buying or renovating, if answers are missing, or if you see cracks in the structure. After an earthquake, the standard itself provides for a civil engineer to assess structures and decide whether they should be repaired, strengthened or demolished. For the rest of choosing a long-stay home, see staying several weeks in Lima.

Tsunamis

A wave unlike the others

A tsunami is a series of waves caused by the sudden displacement of a large mass of water, most often by an earthquake under the sea, sometimes by an eruption or an underwater landslide. It is not a big storm wave. Ordinary waves and swell are formed by the wind and only stir the surface; the tide rises and falls slowly, on a predictable timetable. A tsunami, on the other hand, sets the whole depth of the ocean in motion: out at sea it goes almost unnoticed and travels as fast as a jet airliner, then slows down and grows as it nears the coast (NOAA).

On land, it looks less like a breaking wave than a rapid rise of the sea, which surges far inland with violent currents, then pulls back. Several waves arrive, sometimes for hours, and the first is not necessarily the highest (NOAA).

When can an earthquake cause one?

An earthquake causes a tsunami when it suddenly lifts or drops the seabed over a large area. In Peru, it is above all the great interface earthquakes, under the sea and shallow, that can do so: those of 1746, 2001 and 2007 all produced one. A deep earthquake, like the one in 2019 or the Ayacucho earthquake in 2026, or an earthquake beneath the continent, does not move the ocean floor.

Near or distant origin

A near-source tsunami comes from an earthquake off the Peruvian coast. The shaking is felt, and the wave can arrive within minutes: in Camaná in 2001, about a quarter of an hour later. The earthquake itself is the first warning.

A distant tsunami comes from an earthquake on the other side of the Pacific. You feel nothing, but there are several hours to spare, and it is the official alerts that warn you. In July 2025, after a very strong earthquake off Russia, the Peruvian Navy issued a tsunami alert; the Ministry of Foreign Trade and Tourism asked visitors not to board boat trips and to stay away from the shore while the alert lasted (MINCETUR).

Terrain, inundation maps and alerts that change

The danger depends on the terrain. A beach, a low bay, a port or a river mouth are exposed; ground higher up much less so. In Lima, the Costa Verde beaches stretch out at the foot of the cliffs, and La Punta and part of Callao are low-lying: during the 2007 earthquake, the sea came several metres into some streets of Callao, according to the IGP. But no neighbourhood is “protected” as a whole: what counts is the height of the exact spot and the way to get there.

In Peru, the Navy, through its Directorate of Hydrography and Navigation (DHN), runs the National Tsunami Warning Centre (CNAT) and publishes inundation maps for coastal towns. Municipalities signpost evacuation routes (“ruta de evacuación”) to safe zones on high ground; INDECI also mentions buildings identified as suitable for vertical evacuation, where no high ground can be reached on foot.

An alert is not fixed. Just after an earthquake, its location and a provisional magnitude are known; the bulletins then become more precise as sea-level measurements come in. An alert can therefore be raised, kept or lifted within a few hours. People return to the shore only when the authorities allow it: the end of an alert does not always mean that all danger has passed (NOAA).

The natural signs that mean you should leave

With a near-source tsunami, there is sometimes no time to wait for an official message. The US National Weather Service (NOAA) describes three natural warning signs; any one of them is enough to act:

• strong shaking, making it hard to stand, or long shaking;
• unusual behaviour of the sea: a rapid rise, like a flood, or on the contrary a sudden withdrawal that exposes the seabed;
• a roar from the ocean, like a train or an aeroplane.

The sea does not always draw back before a tsunami: the first wave can arrive without any withdrawal. INDECI advises moving away from the sea after an earthquake until the possibility of a tsunami has been ruled out (INDECI).

What to do: before, during, after

Official Peruvian guidance separates two moments: protecting yourself during the shaking, then evacuating once it stops and you can do so safely. During national drills, INDECI asks people to stay in a safe zone for the first two minutes, then to evacuate in an orderly way to the outdoor safe zones and assembly points (INDECI, October 2026).

Before

• At your hotel or accommodation, locate the exits, the stairs and the “Zona segura en caso de sismo” signs, which show the place chosen by the establishment.
• Keep a small supply within reach: water, a torch, a charged phone, personal medicines, a copy of your passport. INDECI recommends that families keep an emergency backpack (water, tinned food, torch, battery radio, medicines, blankets).
• Note the emergency numbers: SAMU 106, fire brigade 116, police 105. See also everyday safety.
• By the sea, find the evacuation route and the nearest high ground as soon as you arrive.

During the shaking

After

• Expect aftershocks and do not go into a damaged building.
• If you smell gas, get out and raise the alarm; INDECI advises checking for gas leaks after an earthquake.
• Text rather than call: lines quickly become saturated, messages get through better (INDECI).
• Follow official information: the IGP for the earthquake, the Navy (DHN) for a tsunami, INDECI and local authorities for instructions. Let your family and friends know you are safe.

Drills. Peru holds national drills (simulacros) several times a year, announced in advance by INDECI; the third of 2026 was set for 13 October, at 20:00. If you are in the country during one of them, you will hear sirens and may receive a message on your phone: simply follow the instructions of the staff at your hotel or wherever you are.

Predicting, estimating, detecting, warning

These four words do not mean the same thing.

Predicting an earthquake would mean announcing its date and time, its location and its magnitude in advance. According to the USGS, no scientist has ever predicted a major earthquake, and nobody knows how to (USGS). The SED says the same for Switzerland: no one knows where or when the next strong earthquake will occur.

Estimating the probability is something else. From the history of earthquakes and the measured deformation of the ground, scientists calculate how strong the shaking a place is likely to experience over a long period could be. That is what standard E.030 does with its zones, and what the IGP does when it maps the areas where the plates are building up energy. These estimates are used to build and to prepare, not to set a date.

Detecting means recording an earthquake that has just happened. The IGP network locates earthquakes and publishes its first results within minutes.

Early warning means making use of the first seconds: sensors near the epicentre pick up the start of the earthquake, and a message goes out before the strongest shaking reaches places further away. It is not a prediction, and the closer you are to the epicentre, the shorter the warning, if there is any at all. Peru is building such a Peruvian Earthquake Alert System (SASPe): the IGP developed its sensors, using a technology called ALERT-IGP, and loudspeakers and sirens installed on the coast are to broadcast the alert. At the end of 2025, the head of the IGP said the project was still in development and was aiming for 2026; in 2026, sirens were used during the national drills. At the time of writing, we have found no official announcement that it has entered public service: do not count on it.

Finally, SISMATE is the system that allows INDECI to send messages to the phones in an area, even without credit or data. It is used for a tsunami, a huaico, an eruption or a flood. According to the IGP, the messages received after recent earthquakes gave information after the event; they were not early warnings.

A few misconceptions

“Small earthquakes release energy and keep the big one away.” No. A magnitude 6 earthquake releases about a thousand times less energy than a magnitude 8: it would take about a thousand of them to release the same energy. The IGP explicitly calls for “putting an end to this myth”: a moderate earthquake ruptures a tiny area compared with that of a great earthquake (IGP, August 2026).

“There hasn’t been a big earthquake for a long time, so one is imminent”, or the opposite, “so it won’t happen”. A long quiet period means energy is building up, not that a date is approaching. Nobody can turn that build-up into a calendar.

“A new building can withstand anything.” The standard aims to prevent collapse, not all damage, and a new building complies only if it was well designed and well built.

“The sea always draws back before a tsunami.” Not always: the first wave can arrive without the sea having retreated.

“At the first movement, you should run outside.” Not during the shaking: rushing down stairs or under facades is how people get hurt. Protect yourself first, evacuate afterwards.