Earthquakes can seem strangely unfair.
Countries such as Japan, Indonesia, Türkiye, Chile and the Philippines experience damaging earthquakes relatively often, while many other parts of the world can go decades without a major one.
Why?
The answer is not that the ground beneath earthquake-prone countries is simply "weaker."
It has much more to do with where those places sit on Earth's moving tectonic plates, how faults accumulate stress, and what is happening deep beneath the surface.
To understand why earthquakes cluster in certain parts of the world, we first need to understand something remarkable about the planet beneath our feet:
Earth's outer surface is constantly moving.
Earth Is Not One Unbroken Shell
When you look at a globe, Earth's surface appears continuous.
It isn't.
The planet's rigid outer layer is broken into enormous sections called tectonic plates.
These include the:
African Plate;
Eurasian Plate;
North American Plate;
South American Plate;
Pacific Plate;
Antarctic Plate; and
Indo-Australian Plate,
along with several smaller plates.
These plates fit together somewhat like pieces of a gigantic, irregular puzzle.
But unlike an ordinary puzzle, the pieces are moving.
According to the United States Geological Survey's explanation of plate tectonics, tectonic plates move slowly over geological time, generally at rates measured in centimetres per year.
That may sound insignificant.
But when enormous sections of Earth's crust push against one another for decades or centuries, tremendous stress can accumulate.
Eventually, something has to give.
That sudden release of energy is what produces many earthquakes.
What Actually Causes an Earthquake?
Rocks in Earth's crust are constantly subjected to forces.
Along a fault, blocks of rock may be trying to move past one another but become temporarily stuck because of friction.
The tectonic plates don't necessarily stop moving just because the fault is stuck.
Stress continues to build.
Eventually, the accumulated stress becomes greater than the friction holding the rocks in place.
The rocks suddenly slip.
Energy stored in the rocks is released and travels outward through Earth as seismic waves.
Those waves cause the shaking we experience as an earthquake.
A useful analogy is bending a stick.
You can apply force gradually without seeing much happen at first. But the stress is accumulating. Eventually, the stick reaches a point where it can no longer accommodate the force and suddenly breaks.
Earthquake faults behave differently from sticks, but the analogy helps explain how a gradual process can produce a sudden event.
What Is a Fault?
A fault is a fracture or zone of fractures in Earth's crust where blocks of rock have moved relative to one another.
Not every fault is constantly producing earthquakes.
Some faults move slowly.
Others may remain apparently quiet for very long periods while stress accumulates.
This is one reason the absence of a recent earthquake does not automatically mean an area has no earthquake hazard.
Geologists study faults, historical earthquakes, rock deformation and plate movement to understand seismic hazards.
Why Do Plate Boundaries Have So Many Earthquakes?
Most of the world's earthquakes occur near the boundaries between tectonic plates.
That is because plate boundaries are where enormous pieces of Earth's lithosphere interact.
There are three basic ways they can interact.
1. Plates Can Move Apart
At divergent boundaries, tectonic plates move away from one another.
As the plates separate, magma from below can rise and contribute to the formation of new crust.
This occurs prominently along mid-ocean ridges.
Earthquakes at divergent boundaries are often relatively shallow.
One famous example is the Mid-Atlantic Ridge, which runs through the Atlantic Ocean.
Iceland sits directly on this tectonic boundary, helping explain why the country experiences both significant volcanic and earthquake activity.
2. Plates Can Collide
At convergent boundaries, plates move toward one another.
Sometimes one plate is forced beneath another in a process known as subduction.
These environments can generate some of the largest earthquakes on Earth.
They can also produce volcanoes and, when major movement occurs beneath the ocean, potentially generate tsunamis.
Japan is located near the interaction of several tectonic plates.
Indonesia also lies within an extremely active tectonic region.
Their geography is therefore fundamentally different from that of countries situated far from highly active plate boundaries.
3. Plates Can Slide Past Each Other
At transform boundaries, plates move horizontally past one another.
The movement is rarely perfectly smooth.
Fault sections can lock, allowing stress to accumulate before suddenly slipping.
The San Andreas Fault in California is one of the world's best-known examples.
The Pacific Plate and North American Plate move horizontally relative to one another along this fault system.
Why Is the Pacific 'Ring of Fire' So Active?
If you look at a global map of earthquakes and volcanoes, one region immediately stands out.
A huge zone of activity surrounds much of the Pacific Ocean.
It is commonly called the Ring of Fire.
The name does not describe an actual ring. Instead, it refers to a broad horseshoe-shaped region containing numerous plate boundaries, subduction zones, volcanoes and earthquake-producing faults.
Countries and territories around this zone include parts of:
Japan,
Indonesia,
the Philippines,
New Zealand,
Papua New Guinea,
Russia,
Alaska,
the western United States,
Mexico,
Central America,
Peru,
and Chile.
The USGS explains the relationship between earthquakes and tectonic plate boundaries, which helps explain why seismic activity is concentrated around the Pacific.
This concentration is one reason countries such as Japan and Chile experience major earthquakes far more frequently than many countries in West Africa.
Why Does Japan Have So Many Earthquakes?
Japan sits in one of the most tectonically complicated regions on Earth.
Several major plates or plate systems interact around the Japanese islands.
Subduction occurs offshore, where oceanic crust descends beneath other plates.
This tectonic environment produces frequent earthquakes.
Japan's exposure has also influenced how the country designs buildings, develops earthquake-warning systems, conducts drills and prepares its population.
Earthquakes cannot be prevented, so countries with high seismic risk focus heavily on reducing what happens when the shaking starts.
Why Does Indonesia Have So Many Earthquakes?
Indonesia stretches across another highly active tectonic region.
Several tectonic plates interact around the archipelago, including major subduction zones.
This helps explain why Indonesia experiences both frequent earthquakes and extensive volcanic activity.
It also creates tsunami risk.
The devastating 2004 Indian Ocean earthquake occurred off the coast of northern Sumatra.
The undersea earthquake displaced an enormous volume of water and generated a tsunami that affected countries across the Indian Ocean.
This illustrates an important point:
An earthquake does not need to occur directly beneath a city to become a major disaster.
Its secondary effects can travel far beyond the original rupture.
Why Is Türkiye Also Earthquake-Prone?
Türkiye provides a different but equally important example.
The country lies in a tectonically active region where several plates and smaller crustal blocks interact.
Major fault systems, including the North Anatolian Fault and East Anatolian Fault, accommodate some of this movement.
Large populations and cities located near active faults mean that earthquakes can have severe consequences.
The devastating earthquakes affecting Türkiye and Syria in February 2023 demonstrated how the combination of a powerful earthquake, vulnerable buildings and large exposed populations can turn a geological event into a humanitarian catastrophe.
Does Africa Experience Earthquakes?
Yes.
Africa is not earthquake-free.
One of the continent's most important tectonic features is the East African Rift System.
This enormous zone extends through parts of eastern Africa and represents an area where Earth's crust is gradually stretching and pulling apart.
Countries around the rift can experience earthquakes as well as volcanic activity.
The system passes through or influences areas associated with countries including Ethiopia, Kenya, Uganda, Rwanda, Tanzania and others.
Over extremely long geological periods, continued rifting could dramatically change the geography of eastern Africa.
But this process occurs over millions of years, not within a human lifetime.
What About Nigeria?
Nigeria is generally considered to have a lower earthquake hazard than highly active plate-boundary countries such as Japan, Indonesia or Chile.
Nigeria lies within the African Plate and is relatively far from the world's most active plate margins.
But "lower risk" does not mean "earthquakes are impossible."
Nigeria has experienced earth tremors and seismic events.
Some have been felt in parts of southwestern and north-central Nigeria.
Earthquakes can occur within tectonic plates rather than only along their edges. These are known as intraplate earthquakes.
Old faults and zones of weakness in the crust can sometimes become reactivated when stresses act on them.
This is why even regions far from major plate boundaries may occasionally experience earthquakes.
AnjKreb has previously documented examples of major historical earthquakes around the world in List of Some Powerful Earthquakes in History.
That older record provides useful examples of just how widely earthquake magnitude and consequences can vary.
Can Earthquakes Happen Far From Plate Boundaries?
Yes.
Although plate boundaries account for much of global earthquake activity, earthquakes also occur within plates.
These are intraplate earthquakes.
They can happen when stresses reactivate ancient faults or other weaknesses in the crust.
Because some intraplate regions experience large earthquakes only rarely, communities may have little cultural memory of major seismic events.
Buildings may also have been designed with less consideration for earthquake resistance.
A rare earthquake can therefore still be consequential.
Why Are Some Earthquakes More Destructive Than Others?
Magnitude matters, but magnitude alone does not determine how destructive an earthquake becomes.
Several factors influence the consequences.
Depth
A shallow earthquake can produce stronger surface shaking near the rupture than a similar earthquake occurring much deeper underground.
Distance
Communities closer to the rupture generally experience stronger shaking, although local geology also matters.
Building quality
Poorly constructed buildings can collapse during shaking that better-engineered structures survive.
This is one of the biggest differences between an earthquake as a natural event and an earthquake as a disaster.
Population density
An earthquake beneath an uninhabited region may cause relatively little human loss.
A similar event near a densely populated city can be catastrophic.
Local soil
Soft sediments can sometimes amplify shaking.
Some water-saturated soils can also experience liquefaction, temporarily losing strength during intense shaking.
Time of day
An earthquake occurring when millions of people are sleeping indoors can produce different patterns of casualties from one occurring at another time.
Preparedness
Building codes, emergency planning, public education, early-warning systems and emergency-response capacity can significantly influence outcomes.
What Is the Difference Between Magnitude and Intensity?
These terms are sometimes used as though they mean the same thing.
They do not.
Magnitude describes the size of an earthquake at its source and the energy released.
Intensity describes the strength of shaking and its effects at a particular location.
One earthquake therefore has a magnitude, but its intensity can vary from place to place.
A community close to the rupture may experience severe shaking while another hundreds of kilometres away barely notices the same earthquake.
Is the Richter Scale Still Used?
People frequently say an earthquake measured "7.0 on the Richter scale."
The Richter scale played an important historical role in earthquake science, but modern seismologists commonly use moment magnitude, written as Mw, particularly for larger earthquakes.
Moment magnitude estimates earthquake size using characteristics of the fault rupture, including the area that slipped, the amount of movement and properties of the rocks involved.
The USGS provides further explanation through its earthquake magnitude, energy release and shaking-intensity resources.
Is a Magnitude 8 Earthquake Just Slightly Stronger Than Magnitude 7?
No.
Earthquake magnitude scales are logarithmic.
That means the difference between magnitude 7 and magnitude 8 is much larger than the numbers make it appear.
An increase of one whole magnitude represents approximately 32 times more energy release.
So a magnitude 8 earthquake releases roughly 32 times as much energy as a magnitude 7 earthquake.
A magnitude 9 event releases vastly more energy again.
This is why seemingly small differences in earthquake magnitude can represent enormous differences in physical energy.
What Is an Epicentre?
When an earthquake begins underground, the point where rupture starts is called the hypocentre, or focus.
The epicentre is the point on Earth's surface directly above the hypocentre.
News reports often identify an earthquake by the location of its epicentre.
But an earthquake rupture can extend across a substantial fault area, particularly during very large earthquakes.
So thinking of a major earthquake as energy coming from one tiny point can also be misleading.
What Are Aftershocks?
A major earthquake changes the stress in surrounding rocks.
The crust then adjusts to its new state.
This can produce additional earthquakes known as aftershocks.
Aftershocks may continue for days, weeks, months or even longer after a large earthquake.
Most are smaller than the main earthquake, but they can still be dangerous.
Buildings already weakened by the initial earthquake may collapse during subsequent shaking.
Can Animals Predict Earthquakes?
Stories about animals behaving strangely before earthquakes have existed for centuries.
Animals may indeed respond to environmental changes humans do not immediately notice.
However, there is currently no scientifically reliable method of using animal behaviour to predict the precise location, time and magnitude of an impending earthquake.
A dog behaving strangely or birds suddenly moving should not be treated as an earthquake-warning system.
Can Scientists Predict Earthquakes?
Scientists can identify earthquake hazards.
They can map faults, measure plate movement, study historical earthquakes and estimate the probability of significant earthquakes occurring within particular regions over long periods.
What scientists currently cannot reliably do is say something like:
"A magnitude 7.4 earthquake will strike this city at 3:17 p.m. next Tuesday."
This distinction is important.
Forecasting long-term probability is possible. Precise earthquake prediction is not currently possible.
What About Earthquake Early-Warning Systems?
Early warning is different from prediction.
An earthquake early-warning system detects an earthquake after it has already begun.
Electronic signals travel much faster than the destructive seismic waves moving through the ground.
Sensors near the earthquake can therefore detect the initial waves and rapidly transmit warnings to locations farther away.
Depending on distance, people might receive several seconds or sometimes more warning before stronger shaking arrives.
That may not sound like much.
But even a few seconds can allow trains to slow, machinery to stop, medical procedures to pause and people to take protective action.
Can Human Activities Cause Earthquakes?
Not every earthquake is purely natural.
Certain human activities can alter stresses underground and induce seismic events.
Examples can include:
filling very large reservoirs;
mining;
withdrawing or injecting fluids underground;
geothermal operations; and
some oil and gas activities.
These are known as induced earthquakes.
Most induced seismic events are small, but some have been large enough to cause concern and damage.
This does not mean ordinary human activity is responsible for the world's major tectonic earthquake zones.
Plate tectonics remains the dominant explanation for global earthquake distribution.
Can Climate Change Cause Tectonic Earthquakes?
Climate change is not the reason Japan, Indonesia or Chile sit in highly active earthquake zones.
Those earthquake patterns are primarily controlled by plate tectonics.
Changes in glaciers, water loading and other surface conditions can affect stresses in Earth's crust in some circumstances, and scientists study these relationships.
But it would be misleading to describe ordinary large tectonic earthquakes as simply being "caused by climate change."
The underlying plate movements operate on geological processes that long predate modern climate change.
Can an Earthquake Cause a Tsunami?
Yes, but not every earthquake does.
Large undersea earthquakes can generate tsunamis when they cause substantial vertical displacement of the seafloor.
That sudden movement displaces the water above it.
The resulting waves can travel across entire ocean basins.
Tsunamis can also be generated by volcanic activity, underwater landslides and certain other events.
The USGS provides an explanation of how earthquakes can generate tsunamis.
Why Can't We Stop Earthquakes?
The forces moving tectonic plates operate on a planetary scale.
Humans do not have a practical way to stop major tectonic plates from moving or safely release the enormous stresses accumulated across major faults.
Earthquake safety therefore focuses on a more realistic objective:
reducing vulnerability.
That means understanding where hazards exist, constructing safer buildings, strengthening vulnerable structures, improving emergency planning and teaching people what to do during shaking.
What Should You Do During an Earthquake?
Advice depends partly on where you are and the type of building around you.
A widely used safety recommendation when indoors is:
Drop. Cover. Hold On.
Drop to your hands and knees.
Take cover under a sturdy table or desk where possible.
Protect your head and neck.
Hold on until the shaking stops.
Avoid running outside through areas where glass, masonry and other materials may be falling.
People living in earthquake-prone regions should follow the specific emergency guidance issued by their local authorities.
Why Earthquakes Become Disasters
Perhaps the most important lesson from earthquake science is that an earthquake and an earthquake disaster are not exactly the same thing.
An earthquake is a geological event.
The scale of the disaster depends greatly on what humans have built above it.
A powerful earthquake in a sparsely populated region may kill no one.
A smaller earthquake beneath a densely populated city containing vulnerable buildings may kill thousands.
This is why earthquake preparedness is not simply a geology problem.
It is also an engineering, urban-planning, governance and public-safety problem.
Frequently Asked Questions
Where do most earthquakes happen?
Most occur around tectonic plate boundaries, with particularly intense activity around the Pacific Ring of Fire.
Why does Japan have more earthquakes than Nigeria?
Japan lies near several highly active tectonic plate boundaries and subduction zones. Nigeria is located within the African Plate and much farther from the world's major active plate margins.
Can Nigeria experience an earthquake?
Yes. Nigeria's overall earthquake hazard is lower than that of countries such as Japan or Indonesia, but intraplate seismic events and earth tremors can occur.
What is the biggest earthquake ever recorded?
The largest instrumentally recorded earthquake was the 1960 Valdivia earthquake in Chile, estimated at magnitude 9.5.
For examples of other historically powerful earthquakes, see AnjKreb's List of Some Powerful Earthquakes in History.
Does a magnitude 8 earthquake have twice the energy of magnitude 7?
No. The magnitude scale is logarithmic. An increase of one magnitude corresponds to roughly 32 times greater energy release.
Can scientists tell exactly when the next earthquake will happen?
No. Scientists can assess earthquake hazards and probabilities, but precise prediction of the time, place and magnitude of a major earthquake is not currently possible.
Are earthquakes becoming more common?
Modern instruments detect many earthquakes that people in previous centuries would never have recorded. Short periods containing several major earthquakes do not necessarily mean that global tectonic activity is permanently increasing.
The Bottom Line
Earthquakes happen more often in some places because Earth's crust is divided into moving tectonic plates, and much of the planet's seismic activity is concentrated where those plates interact.
Japan, Indonesia, Chile and other earthquake-prone countries happen to sit near particularly active plate boundaries.
Nigeria sits much farther from the major global plate boundaries, so damaging earthquakes are less frequent, although they are not impossible.
And the severity of an earthquake disaster depends on much more than geology.
Where people build, how buildings are constructed, how densely communities are populated and how well societies prepare can determine whether powerful ground shaking becomes a manageable emergency or a catastrophe.
Earthquakes may be natural.
Disaster risk is partly something societies can change.
References and Further Reading
United States Geological Survey (USGS) – The Science of Earthquakes
https://www.usgs.gov/programs/earthquake-hazards/science/science-earthquakes
USGS – Can You Predict Earthquakes?
https://www.usgs.gov/faqs/can-you-predict-earthquakes
USGS – Earthquake Magnitude, Energy Release and Shaking Intensity
https://www.usgs.gov/programs/earthquake-hazards/earthquake-magnitude-energy-release-and-shaking-intensity
USGS – Tsunamis and Earthquakes
https://www.usgs.gov/programs/earthquake-hazards/science/tsunamis-and-earthquakes
USGS – Earthquake Hazards Program
https://earthquake.usgs.gov/
British Geological Survey – Earthquakes
https://www.bgs.ac.uk/discovering-geology/earth-hazards/earthquakes/
Related on AnjKreb
List of Some Powerful Earthquakes in History
https://anjkreb.blogspot.com/2016/11/list-of-some-powerful-earthquakes-in.html
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