Although earthquakes cause about 80% of tsunamis, almost all earthquakes lack sufficient energy to cause the sudden shift in the ocean floor needed to substantially displace enormous volumes of water.

A tsunami—Japanese for 'harbor wave'—can begin with a drop in sea level before rising, which has contributed to its mistaken categorization as a tidal wave, despite being unrelated to the moon's gravity.

Rather than being triggered by a massive displacement of water from a geological event, meteotsunamis are caused by rapid changes in air pressure from fast-moving weather systems.

Tsunamis are a series of waves rather than a single one, and boats are safer from them in deeper waters, where tsunami waves are smaller.

Tectonic earthquakes are caused by tectonic plates sliding past one another at fault zones, deforming rock through friction as energy builds like a stretched rubber band.

Deep-sea trenches form when one tectonic plate subducts another underwater

Oceanic plates sink when colliding with less dense continental plates, bending the seafloor into steep depressions that can be almost 11 kilometers deep. Many of Earth’s strongest earthquakes occur at these plate boundaries, often featuring volcanic activity.

Wave tanks can be used to create and study the impacts of tsunamis by building tension in an underwater object before allowing it to slip and rapidly displace water.

Earthquakes of identical magnitudes are unlikely to cause equal damage because magnitude only measures energy released, and earthquake severity depends on environmental factors, such as local architecture and geological conditions.

Because seismic waves travel 100 times faster than tsunami waves—waves typically travel faster through solids than liquids—measurements of geological activity help tsunami detection systems provide early warnings.

The frequency of earthquakes and the distribution of their magnitudes have not changed significantly over long-term records, but technological improvements have enabled scientists to detect more of them as they occur.

The tallest tsunami in recorded history was 524 meters (1,720 feet) high—taller than the Empire State Building—and occurred in Lituya Bay, Alaska, in 1958 after an earthquake dislodged a rockface into the water.

Tsunamis can last for days as their successive waves hit a coastal area, with early warning systems indicating the likelihood of a tsunami's arrival on a scale from watch to advisory to warning.

Visualize the power and frequency of earthquakes across the moment magnitude scale, where a whole number increase corresponds to about 32 times more energy released.

Most volcanic activity occurs in submarine volcanoes on the seafloor

At divergent plate boundaries in mid-ocean ridges, volcanic activity produces new ocean crust as the seafloor spreads. These areas are home to underwater mountains with extensive biodiversity due to redirecting ocean currents and concentrating food for marine life.

View a tsunami travel time map to learn how many hours its waves are estimated to take to reach different parts of Earth when originating from a list of geologically active locations.

When oceanic plates sink beneath tectonic ones, they can generate magma

At converging oceanic-continental plate boundaries, the subduction of the oceanic plate introduces seawater that reduces the melting temperature of the overlying mantle. This causes it to melt into less dense magma, which can rise to fuel more volcanic activity.

Likened to a car backfiring or a faraway cannon fire, skyquakes have been reported worldwide in Earth's atmosphere without any obvious cause.

Research suggests a 95-kilometer-wide (59-mile-wide) asteroid impact could boil the Earth's oceans

Even a 1-kilometer-wide (0.62-mile-wide) asteroid can trigger earthquakes and tsunamis on impact with oceans. The overwhelming majority of asteroids that reach Earth are much smaller and burn up in the atmosphere before reaching the ground.

Explore an interactive time-lapse of reported tsunami events since 1850, with identified cause, recorded observations, known deaths, and other information available for each.

Some earthquakes can produce smaller tremors called boomerang earthquakes, which travel in the opposite direction and ripple back to the original earthquake's source.

38 thought-provoking facts about the ocean

Coral produces its own sunscreen, tsunamis move at 500 miles per hour, one of the loudest sounds ever recorded came from an ice quake, and other interesting facts collected from sources such as National Geographic and NASA.

View maps of seafloor topography, earthquakes, and volcanic activity, which scientists use to create outlines of Earth's tectonic plates.

A magnitude 25 earthquake would release enough energy to destroy the sun, while a particle of dust drifting onto a table would have a magnitude of about -15.

The moon's gravity exerts an overall pressure that displaces the oceans toward the opposite sides of Earth's equator, producing tides.

Rather than predicting them in advance, earthquake early warning systems detect tremors moments after they begin and send notifications that reach users before the seismic activity does.

View the 10 largest earthquakes ever recorded as of 2025, led by a 1960 magnitude 9.5 earthquake in Chile, which left about 2 million people unhoused.

The Ring of Fire, which spans 40,000 kilometers (24,900 miles) around the Pacific Ocean, is the most geologically active region on Earth.

View a map of the world's major earthquakes from 1956 to 2022, which can be used to identify tectonic plate boundaries.

Predicting earthquakes is difficult because different rock types can withstand different amounts of stress before breaking and melt at different temperatures within Earth's interior, introducing uncertainty into predictive models.

Thunderquakes—seismic waves created when lightning strikes the ground—have enabled scientists to image underground environments near Earth's surface by detecting vibrations along subterranean fiber-optic cables.

From 1610 BCE to 2025 CE, at least 250 of the over 3,000 confirmed tsunamis were deadly, and the 2004 Indonesia tsunami was the deadliest, with over 227,000 casualties.

The four types of seismic waves—vibrations that carry energy generated by geological events, such as earthquakes—are categorized as body or surface waves.

Infrastructure built to limit tsunami damage includes channels to divert water, floodgates, and seawalls, such as the approximately 400-kilometer (249-mile) wall built in Japan after the 2011 Tōhoku earthquake and tsunami.

Scientists determine earthquake locations by comparing how long it takes different seismic waves to be detected at three stations around the world, from which an origin, or hypocenter, can be triangulated.

Scientists determined that tectonic plates moved the ocean floor by observing symmetric patterns of magnetic stripes on opposite sides of underwater volcano systems, which could only result from seafloor spreading.

How the Turkish earthquake created a 100-mile rupture

A February 2023 earthquake devastated parts of Turkey and Syria destroying entire blocks, with more than 50,000 people killed. A scientific analysis revealed a fault line with a 100-mile-long rupture, where separate tectonic plates moved more than...

Some tectonic plates move faster than their underlying convection currents

Like a chain slipping off a ledge, as tectonic plates sink, their weight can pull the rest of the trailing plate forward, accelerating their movement. Plates can also break apart and fall, creating a suction effect that drives movement, resembling leaves following a passing car.

NASA's GUARDIAN software uses changes in satellite navigation signals and AI-powered detection algorithms to anticipate tsunamis and provide real-time alerts to at-risk communities before the phenomena are detected by tidal sensors.

If, not when: An earthquake is destined to destroy the Pacific Northwest.

When the Cascadia fault line ruptures, it could be North America’s worst natural disaster in recorded history. Read a deep dive into the history of the region and the potential impact of the eventual seismic boom.

What makes the Earth shake?

Researchers are demystifying the science of earthquakes—from their origins deep within the Earth to the scales that measure their strength. This article, which was part of a series of weekly reports from Cornell University, serves as a guide to...

Explosive volcanic eruptions happen when magma pressure overcomes rock strength

Magma usually stays underground because of a balance between its upward pressure, the weight of the Earth’s crust above, and the crust’s rock strength. Landslides can reduce crust weight, while built-up gas pressure can strengthen magmastatic pressure.

Micro-seismic activity has been produced from people cheering or dancing at sporting events, concerts, and other large gatherings, but scientists can easily distinguish these vibrations from natural earthquakes using seismometers.

How the moon creates tides

Anyone who has visited large bodies of water virtually anywhere on Earth notices low and high tides occur at regular intervals, a process primarily driven by the moon’s gravitational pull. This explainer details how the motion of the Earth and Moon interact to create tides.

Just as light bends at different angles as it travels through different materials, seismic waves move in different directions through Earth's interior, revealing the presence of layers with varying properties.

Earth is constantly bombarded by material from space

Most of this matter is composed of small particles, with any smaller than 33 feet in diameter burning up in the atmosphere. Larger asteroids can reach the ground, and those larger than several thousand feet cause global damage, including earthquakes and tsunamis.

The San Andreas Fault is an example of tectonic plates sliding past each other

The transform boundary divides the opposing movements of the Pacific and North American tectonic plates, which create shear zones that distort and fracture rock. These movements produce shallow earthquakes as rocks are gradually displaced hundreds of miles.

Enhanced geothermal power systems can trigger earthquakes by injecting fluid into rock, increasing subterranean pressure.

The world's largest earthquake simulator is an 800-ton shake table facility in Miki, Japan, which was built to test the resilience of structures after the 1995 Kobe earthquake killed over 6,000 people.

Reported earthquake magnitudes often change because initial values are based on limited information, whereas revised magnitudes account for factors such as fault size, rupture duration, and seismic wave behavior.

Explore an interactive map of volcanoes, earthquakes, and tsunamis from 2150 BCE to the present.

Convection flows in Earth’s mantle drive the movement of tectonic plates

These processes transfer heat from Earth’s core to the surface via rising magma plumes, while cooler, denser rock falls into the mantle at rates similar to human fingernail growth. These rates are determined by combining seismic data with computer simulations to model Earth’s interior.