View a gallery of diagrams for each volcano type with glossaries

Lava flow viscosity plays a significant role in the type of volcano formed

Thin, runny flows spread quickly before cooling, producing expansive layers that build over time into wide shield volcanoes. The ejection and fast hardening of thicker lava flows and pyroclastic material create steep slopes and the characteristic cone shape of composite volcanoes.

Volcanoes can be active, dormant, or extinct based on the recency of eruptions

Active volcanoes may be in the process of erupting or expected to erupt in the future, having done so within the past 11,650 years. Dormant volcanoes have no short-term eruption history, but are expected to erupt in the future, while extinct volcanoes lack the history and expectation.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

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

Eruption forecasting relies on probabilistic methods resembling weather forecasting

While some volcanoes erupt with predictable signs, such as surface deformation from the build-up of underground magma pressure, others release magma at inconsistent rates. Extensive monitoring is needed to identify less clear patterns and indicators of future eruptions.

Yellowstone National Park is situated atop an active supervolcano

Yellowstone showcases geothermal phenomena, including the famous Old Faithful geyser and the vibrant Grand Prismatic Spring. The park's unique geological and ecological features make it an exceptional destination for visitors from around the globe.

The composition of magma affects the explosivity of volcanic eruptions

Silicate-rich magma contains extensive molecular chains that trap dissolved gases like water and carbon dioxide. These gases build pressure until they violently escape, creating explosive eruptions. Low-silica magmas produce gentler eruptions categorized as effusive.

Explore case studies of each type of convergent plate boundary

At these boundaries, a collision of two oceanic plates produces a curved chain of volcanic islands, like those seen in the Caribbean. A continental-continental plate collision results in plates buckling upward, forming large mountain ranges.

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.

Vesuvius has erupted nearly 40 times since Pompeii

With a 17,000-year history and dozens of eruptions since 79 CE, Vesuvius sits atop volatile geological forces that make it an unusually explosive volcano. This explainer breaks down why the volcano remains dangerous today.

See Mount Vesuvius from space

Mount Vesuvius is one of the few active volcanos on Europe's mainland. See it from space in this photo from NASA's Earth Observatory. This natural-color image was taken on January 2, 2022, during a break in cloud coverage.

View examples of rift valleys, the product of surface divergent boundaries

At these boundaries, tectonic plates move apart, stretching and thinning Earth’s crust as long valleys are formed from smaller, interconnected valleys and troughs. Ongoing rifting and erosion can further sink the valley, becoming a rift lake if volcanic activity becomes inactive.

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.

With a height three times that of Mount Everest and an area roughly the size of Poland, the Martian shield volcano Olympus Mons is the largest volcano in the solar system.

The deadliest aspect of volcanic eruptions is often not lava, but pyroclastic flows—avalanches of ash, gas, and rock that can move more than half the speed of sound.

Extraterrestrial volcanoes spew material present during their formation

Unlike Earth's volcanoes that release lava, cryovolcanoes on distant moons erupt cold jets of water, ammonia, and other light gases present during the formation of their host planet. The movement of internal heat produced during formation is thought to drive icy plume movement.

The volcano threatening the Greek island of Santorini

Santorini is a popular tourist destination, known for its stunning white architecture and dreamy blue waters. Yet underneath the charming island is a potentially dangerous underwater volcano. Recent earthquakes have triggered nearly half of residents to evacuate, signaling heightened uncertainty about when the volcano could erupt. Researchers studying activity in the region plan to produce detailed hazard maps for Greek authorities to improve local safety and emergency planning.

View a colorful gallery of solar features, including coronal loops and filamentary prominences, curated by the National Solar Observatory.

Supervolcanoes can eject enough material to fill one-fourth of the Grand Canyon

Although extremely rare, their released material can trigger winters by blocking the sun and cooling the Earth’s surface for years. The Toba supereruption 74,000 years ago disrupted food chains and reduced the human population to a few thousand.

Cerulean eruptions result from sulfur being heated by molten rock

During eruptions, warm-colored lava at temperatures between 700 and 1,200 degrees Celsius (1,300 and 2,200 degrees Fahrenheit) burns minerals as they escape from underground reservoirs. In some volcanoes, such as Indonesia's Kawah Ijen and Ethiopia's Danakil Depression, abundant sulfur compounds that burn with blue flames appear to change the color of the melted rock.

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

Mapping the Tongan eruption impact

A team of scientists—with the help of an uncrewed boat remotely controlled from the UK—join forces to produce one of the clearest pictures to date of what took place underneath the water as an enormous volcano erupted near the Tongan mainland.

An overview of Venus, from its retrograde rotation to its volcanic surface

Boasting over 1,600 major volcanoes—more than any other planet in the solar system—Venus rotates in the opposite direction as Earth, potentially due to a major collision during its formation that flipped the planet upside-down. The planet's rotation also makes days on Venus last longer than its entire year.

Visualize the components of fireworks

This article provides animated diagrams depicting how different parts of fireworks function. The elements work together through timed mechanisms to produce desired effects.

Could we throw trash inside volcanoes?

Americans toss out about 239 million tons of garbage each year. Some have wondered whether we could toss some (or all) of it into volcanoes, where it could be destroyed. There are about 1,500 active volcanoes on Earth, and many are pretty remote, making logistics complex. This video investigates whether the idea checks out.

View a gallery of various auroral shapes

Auroras can be generally classified as discrete (well-defined shapes) or diffuse (hazy shapes), with light taking various forms, including curtains, arcs, pillars, and rays. Some auroras can also pulsate, particularly after intense periods of auroral activity are winding down.

A nearby super volcano poses an even greater risk to Italy than Vesuvius

The Campi Flegrei supervolcano, with over half a million residents nearby, may be the region’s true threat. This BBC short shows how scientists monitor Campania’s volatile geology—and why people remain drawn to the landscape despite the danger.

The art and architecture of the devastated Pompeii

Long buried under feet of ash, the city of Pompeii's discovery millennia later sparked a world of imagination and tragedy. See a collection of paintings, buildings, and photographs from the city all in one easy-to-browse gallery.

Located on Ross Island in Antarctica, Mount Erebus is the southernmost active volcano on Earth and features a lava lake—one of eight known worldwide as of 2026—that erupts regularly.

In 2009, accidentally drilling into magma provided time capsules of volcanic glass

While drilling for geothermal energy in Iceland's Krafla Geothermal Field, magma encountered at a depth of 2,100 meters quickly formed glass upon making contact with drilling fluid. By trapping dissolved gases, volatile chemicals, and the physical characteristics of magma before cooling, the glass acts as a time capsule of ancient volcanic activity and magmatic conditions.

Clouds can be categorized into 10 basic types based on their height and composition.

Among the features of these types, cirrus clouds can display various colors at sunrise and sunset, while altocumulus clouds can produce a corona phenomenon around the sun or moon. Nimbostratus clouds are thick enough to block out the sun entirely.

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.

Human activities release 100 times the carbon dioxide of all volcanic eruptions

While gases released by volcanoes contribute to climate change, humans produce the carbon dioxide equivalent of a Mount St. Helens-sized eruption every 2.5 hours, or more than one Yellowstone eruption yearly, even though such supervolcanoes only erupt about every 100,000 to 200,000 years or more.

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

The average eruption cycle of the Yellowstone supervolcano is 735,000 years

Eruptions a little over 2 million, 1.3 million, and 630,000 years ago indicate that the eruption is not imminent, though the sample size is small. Recent analysis reveals magma pockets are not interconnected, reducing eruption risk.

Dirty lightning is a thunderstorm created from friction between rising and falling flows of ash and smoke during volcanic eruptions.

Scientists monitor volcanoes with a suitcase-sized observatory called SKATE

Short for Setup for the Kinematic Acquisition of Explosive Eruptions, the device is left to record heat, sound and visual data while volcanologists remain at a safe distance. The $58,000 tool is the successor to the FAMoUS (Fast Multiparametric Setup) prototype.

A simple pictorial explanation of ocean geography

Visualizing ocean geographical features, such as a coastal zone, continental shelf and abyssal plain. This article from the US Geological Survey also provides several links to diverse ocean facts.

Explore the collection of vivid frescoes Pompeii left behind

This gallery showcases remarkably preserved frescoes depicting food, daily life, landscapes, and myth. Tools abandoned during the eruption reveal how ancient artists worked, offering insight into Pompeii’s visual culture before Vesuvius buried the city in ash.

View galleries of images taken by the Voyager spacecraft, including close-ups of Uranus, Jupiter's Great Red Spot, Saturn's ring system, and Neptune's Great Dark Spot.

Explore what each organelle does within various types of cells

In "Cell Anatomy Viewer," users can explore interactive illustrations of animal, plant, fungal, and bacterial cells. Clicking on an organelle, such as a lysosome, the nucleolus, or the Golgi complex, provides descriptions of its characteristics and functions.

A volcanic island north of Sicily is the world's longest continuously active volcano

Stromboli has been releasing lava for at least 2,000 years, with the earliest recorded eruption dating back to 350 BCE. Its mild but ongoing bursts of bright lava have earned it the nickname, "lighthouse of the Mediterranean."

Explore a world map of Mars

The yellows spots scattered across the map indicate meteor impacts while the red regions represent volcanoes and their associated lava flows. The varying shades of brown indicate cratered highlands and midlands, which make up most of the southern hemisphere.

View a directory of more than 300 dinosaurs

This resource details each dinosaur's taxonomy, type, diet, and habitat, from Aardonyx to Zuniceratops. More well-researched dinosaurs include information on when they were discovered alongside their size, behaviors, and other noteworthy findings.

Explore a database of ancient graffiti

Take a look at thousands of pieces of graffiti from the walls of Herculaneum and Pompeii, including name tags, crude jokes, and crude drawings. The database, maintained by classical scholars, allows you to explore maps of the cities and images of the original inscriptions.

How powerful was the volcanic blast that destroyed parts of ancient Rome?

This article details how strong Mt. Vesuvius' powerful 79 CE blast may have been. Pompeii lay a bit further from the volcano's slopes than Herculaneum, a smaller seaside city. While Pompeii was mainly destroyed by ash and lapilli—glassy fragments of lava ejected during volcanic eruptions—Herculaneum was first hit by a scorching pyroclastic cloud of volcanic gas and other matter.

The three types of coral reefs—fringing, barrier, and atoll—are categorized by where they form.

Volcanologist survives 5 eruptions while living on Mount Vesuvius

As physicist Luigi Palmieri ducked around lava flowing down the slopes of Mount Vesuvius, he also solidified the field of volcanology. This article details his contribution to science through his dangerous ventures to the volcano that buried Pompeii...

Explore next-generation geothermal projects worldwide

This tool from the Clean Air Task Force allows users to see the location of geothermal power systems to depths of 12.5 kilometers (7.8 miles), where temperatures reach about 450 degrees Celsius (842 degrees Fahrenheit), including proposed, abandoned, and in-development projects.

Many believe a cataclysmic volcanic eruption is imminent at Yellowstone, though experts say it is unlikely

Mike Poland, a scientist at the Yellowstone Volcano Observatory, estimates the likelihood of the event at one in a million. He cautions, though, that the park poses other potential dangers, including steam explosions and earthquakes.