Tsunamis are caused by a massive volume of water being suddenly displaced, as occurs when the seafloor shifts due to geological events such as earthquakes.

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.

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.

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 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.

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.

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.

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.

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.

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.

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

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

How the moon creates tides

Storm surges, not winds, are the leading cause of hurricane-related fatalities

How do hurricanes form?

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.

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

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.

Why do flash floods occur?

Kelvin waves are planetary-scale redistributions of warm water and energy deep beneath the ocean's surface that can raise sea levels by several inches for weeks.

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.

The 'dirty side' of a hurricane is where the likelihood of tornadoes, storm surges, and flooding is greatest.

Thunder occurs when fast-flowing electricity heats and pressurizes air, causing it to expand and produce a shockwave at each point along the bolt at multiple frequencies.

In the US, flash floods—rapid floods that occur within six hours of rain—kill more people than tornadoes, hurricanes, and lightning.

Various types of tornadoes are distinguished by their shape, size, and location

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

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

38 thought-provoking facts about the ocean

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

Some tectonic plates move faster than their underlying convection currents

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.

Why is sea level rising?

Tropical cyclones, which include hurricanes and typhoons, consist of three main parts: the eye, the eyewall, and rainbands.

Quicksand—a mixture of sand with clay or silt soaked in water that gives way when enough pressure is applied—is denser than the human body, meaning you naturally float inside it.

The way hurricanes are categorized may mislead the public to their dangers

What makes the world's biggest waves?

As of 2026, the world's largest tropical cyclone was Typhoon Tip, whose size spanned the equivalent of half the continental US.

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.

After a landslide, repeat activity may follow the appearance of cracks, springs of water, or dirt, sand, and rocks tumbling down from scars—exposed portions of Earth where the initial landslide began.

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

The biggest ocean waves in the world, which regularly reach between 80 and 100 feet, are primarily caused by a 140-mile-long submarine canyon that reaches a maximum depth of 16,000 feet.

Tornadoes produce inaudible signals to humans hours before forming

Hurricane Helene dumped enough water to fill Lake Tahoe

Fast-changing conditions during their formation make tornado forecasting difficult

Massive blooms of microscopic algae called dinoflagellates produce the neon blue light seen in glowing 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.

Available data suggest that while hurricane frequency has not increased over the past century, average hurricane intensity has, a trend scientists attribute to rising air and ocean temperatures.

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

The moon is slowly contracting as its interior cools, creating moonquakes and lobate scarps—cliffs that are steep on one side and gently sloping on the other—as the moon's surface buckles.

Mapping the Tongan eruption impact

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.