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EarthquakesEarthquakes are geological events caused by rocks beneath Earth's surface becoming overwhelmed by mechanical stress and moving suddenly. Mechanical stress comes from the gradual movement of tectonic plates—massive pieces of crust and upper mantle that have drifted for billions of years—which can squeeze, stretch, or twist rocks. Once rocks experience stress beyond a critical point, they fracture and release energy built up while under stress. Earthquakes originate at the focus or hypocenter, where energy is released in all directions as seismic waves. They are felt most intensely at the epicenter—the surface above the focus. Seismologists measure the size of an earthquake on the moment magnitude scale, where each whole-number increase, such as from 4.0 to 5.0, represents a 32-fold increase in released energy. Analyzing these waves has allowed scientists to learn about Earth's interior, identify tectonic plate boundaries, and develop warning systems for tsunamis.Explore Earthquakes

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Engineering tall structures requires managing wind, earthquakes, and other destabilizing factorsReinforced concrete, energy dampers, braced frames, flexible structures, and aerodynamic decks were among the methods implemented when building structures such as the Shanghai Tower, the Texas Super Skyscraper, and the South Rangitīkei Viaduct. Science Channel Boomerang earthquakes reverse direction and ripple back the way they cameComputer simulations show that rapid changes in friction along a fault where an earthquake has traveled for long distances can produce a smaller quake in the opposite direction. Data consistent with the phenomena has only been recorded a handful of times from 2011 to 2023. Discover Magazine Enhanced geothermal power systems can trigger earthquakesThese systems inject fluid into rock to create cracks that allow deeper reservoirs of fluid to escape or to create networks where water can be deposited for heating. This injection can increase subterranean pressure and potentially trigger earthquakes, necessitating the use of sensors and moderated drilling technologies. Undecided with Matt Ferrell Explore an interactive map of historical volcanoes, earthquakes, and tsunamisThe Natural Hazards Viewer allows users to map the locations of major natural hazards from 2150 BCE to the present. Advanced filters allow for various refinement methods, including volcano morphology, earthquake magnitude, tsunami height, deaths, and damage. NOAA Earthquake early warning systems do not predict earthquakesSystems like ShakeAlert® use a network of hundreds of ground sensors to detect earthquakes moments after they begin. Since seismic waves travel about 5 km/s, individuals may be notified of earthquakes before they feel the seismic activity has reached them. Pacific Northwest Seismic Network View a map of the world’s major earthquakes from 1956-2022Such maps can help identify tectonic plate boundaries. The most significant earthquakes are characteristic of converging plates, such as those in the Circum-Pacific Belt and the Alpine-Himalayan Belt, where the Himalayas continue to grow. Visual Capitalist Earthquakes of identical magnitudes are unlikely to cause equal damageThe severity of earthquakes depends on factors beyond the energy released in a region, including local architecture and geological conditions, such as water-saturated soil behaving like quicksand. Secondary effects, such as landslides, floods, and fires, may also contribute. Smithsonian Magazine The Richter scale was only intended to quantify Southern California earthquakesThe scale, designed to rate the energy of the largest seismic waves released by an earthquake, was calibrated to the region’s crust and mantle properties. Since the 1970s, seismologists have instead used the moment magnitude scale, which considers all waves of released energy. Live Science View the 10 largest earthquakes ever recorded as of 2024In 1960, a magnitude 9.5 earthquake in Chile became the largest in recorded history, leaving about 2 million people homeless. Two of the largest occurred in back-to-back years in Alaska, with 9.2 and 8.7 quakes each generating tsunamis. USGS Tectonic earthquakes are caused by interactions of tectonic plates at fault zonesAt these locations, plates slide past one another, deforming rock through friction as energy builds like a stretched rubber band. Volcanic eruptions, the collapse of subterranean caverns, or underground nuclear explosions can also cause earthquakes. Caltech Science Exchange View maps of seafloor topography, earthquakes, and volcanic activityEarthquakes and volcanoes are most common at plate boundaries, where moving plates interact. Mapping the locations of these events creates outlines for the different tectonic plates on Earth, whose movements can be tracked via GPS satellites. National Park Service Why Turkey's earthquakes were so deadlyThe death toll from February 2023 has reached the tens of thousands, making it one of the deadliest natural disasters of the century. The intense seismic activity combined with poor and unregulated construction in many areas to drive fatalities.... Reuters Why starquakes may explain various phenomena associated with neutron starsFast radio bursts—repeated millisecond-long pulses of enormous energy from neutron stars—are emitted with a timing that resembles the earthquakes and aftershocks seen on Earth when geological activity releases energy from within the planet. Although pulsars should gradually spin more slowly as they lose energy from emitting jets of radiation, sudden increases may result from interior matter moving during starquakes. SciShow Space Rocks beneath the Atlantic Ocean are pushing the continents apartUnderwater volcano systems move continent-sized, puzzle-like slabs that make up Earth's surface at about the same rate as fingernails grow. But how do we know these slabs—tectonic plates—exist, and what happens when they collide? Click the title of this resource to find out. 1440 Tornadoes produce inaudible signals to humans hours before formingResearchers at the National Oceanic and Atmospheric Administration have found that tornado-producing storms generate specific sounds below the range of human hearing, much like the infrasonic signals produced by earthquakes and avalanches. Although difficult to distinguish from wind noise, scientists hope to build systems that use these signals to improve tornado forecasting. IEEE Spectrum Many believe a cataclysmic volcanic eruption is imminent at Yellowstone, though experts say it is unlikelyMike 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. Unexplainable Visualize the power and frequency of earthquake magnitudesAbout 150 medium earthquakes—magnitude 6.0—occur every year, resulting in moderate shaking and some property damage. While millions of earthquakes below category 2.0 occur yearly, fewer than one of category 9.0 or higher occurs on average. Visual Capitalist Reported earthquake magnitudes change as more data refines initial estimatesInitial magnitudes are based on limited information, while final magnitudes account for factors like fault size, rupture duration, and seismic wave behavior. Larger earthquakes have the most complex seismic wave activity and often require the most time to finalize recorded magnitudes. IRIS Earthquake Science Tsunamis are caused by sudden seafloor shifts displacing waterEarthquakes of magnitude 7.0 with hypocenters within 100 km of the seafloor can vertically shift large sections of the seafloor significantly. This seismic activity is more commonly found in subduction zones, where an oceanic plate sinks beneath a continental one. NOAA The Ring of Fire is the most geologically active zone on EarthSpanning 40,000 kilometers as it circles the Pacific Ocean, the region experienced about 90% of the world’s earthquakes and contains over 70% of its active volcanoes. The horseshoe-shaped belt features convergent, divergent, and transform plate boundaries. National Geographic Counterweights can dampen the impact of seismic activity on buildingsJapan’s Tokyo Skytree uses a free-moving central column inspired by ancient pagodas, while Taiwan’s Taipei 101 contains a 660-ton pendulum on its 92nd floor that swings out of sync with the building. Interesting Engineering An 800-ton shake table is the world's largest earthquake simulatorAfter the 1995 Kobe earthquake killed over 6,000 people, Japan created E-Defense to reproduce the force of earthquakes and test them against structures as tall as 10 stories, leading to changes in Japanese building codes to reduce collapse rates. Veritasium The movement of seismic waves reveals the structure of Earth’s interiorChanges in temperature, density, and composition alter the path of primary and secondary waves, impacting where they are detected along Earth’s surface. These deflections create shadow zones 104 degrees to 140 degrees away from the epicenter, where no waves are directly detected. SciencePrimer The four types of seismic waves are categorized as body or surface wavesPrimary (P) and secondary (S) waves are compression and shear waves, respectively, and travel through Earth’s interior, though secondary waves only move through solids. These waves’ energy is converted into rolling Rayleigh or horizontal Love waves at the surface. Pacific Northwest Seismic Network A magnitude 25 earthquake would release enough energy to destroy the sunSince Richter and moment magnitude scales rank earthquake energies logarithmically, theoretical magnitude values can cover an enormous range with no upper or lower mathematical limit. A particle of dust drifting onto a table would have a magnitude of about -15. xkcd's What If?The earliest earthquake detection device involved eight ball-wielding dragonsInvented in China in 132 CE, the seismoscope was an urn with dragons facing different directions. If an earthquake occurred, the dragon facing the direction of the tremor released its ball. Like modern seismographs, its mechanism may have involved a suspended weight. Michigan Technological University Differences in seismic wave speeds let scientists determine an earthquake’s locationBecause primary waves are faster than secondary waves, seismic stations will detect longer gaps between these waves’ arrivals the farther an earthquake is. Calculating the distance to the earthquake from three stations allows its origin to be triangulated. Earthscope Consortium Simulate geological activity at plate boundariesYou are given a planetary model with optional rock formation and your choice of the number of tectonic plates and their densities. Draw continents, assign forces and plate boundary types, and run the simulation across map types to observe earthquakes, volcanoes, and other geological activity. Concord Consortium The San Andreas Fault is an example of tectonic plates sliding past each otherThe 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. National Park Service Deep-sea trenches form when one tectonic plate subducts another underwaterOceanic 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. Woods Hole Oceanographic Institution Earth’s major tectonic plates make up 95% of its surfaceTectonic plates are pieces of Earth’s lithosphere, which consists of the crust and the solid, upper layer of the mantle. Segments of major plates can break and form minor or microplates, whose total number varies based on ongoing geological activity. WorldAtlas The resulting climate change, not the asteroid impact itself, killed most dinosaursAlthough the Chicxulub impact caused widespread destruction through earthquakes and tsunamis, the subsequent nuclear winter, acid rain, and eventual greenhouse warming drove mass extinction. Roughly 70% of species, including all non-avian dinosaurs, went extinct. National Science Foundation Research suggests a 95-kilometer-wide (59-mile-wide) asteroid impact could boil the Earth's oceansEven 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. SciShow Portugal's 1775 earthquake is considered Europe's first modern natural disasterAn 8.5-magnitude earthquake off the Portuguese coast nearly destroyed Lisbon, killing thousands, creating 16-foot-wide fissures in the city, and triggering a massive tsunami. Historians credit it with jump-starting the Enlightenment in the region, with many thinkers seeking natural explanations. BBC Global Friction is the force that resists the sliding of surfaces along one anotherFriction always acts to resist movement and is determined by how rough the surfaces are and how hard they are pressed together. In the case of fluids, friction arises from the relative motion between adjacent fluid layers, which act like sliding surfaces. Science News Explores Santa Barbara once had a thriving Chinatown and JapantownIn the late 1800s, the city had an influx of immigrants from China and Japan, prompting the growth of areas dominated by their respective cultures. Earthquakes and world wars, as well as a push for Spanish Colonial architecture, led to their eventual decline. The Bottom Line UCSB Tree rings can reveal centuries of environmental change and natural eventsThe width and shape of tree rings reflect yearly growth conditions like rainfall or snowfall. Scars in the rings can record disruptions such as fires, avalanches, or earthquakes, explaining when and how those events occurred. USGS The volcano threatening the Greek island of SantoriniSantorini 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. BBC Should you get earthquake insurance?Standard home insurance doesn’t typically cover earthquakes. Even if you don't live in a state that's known for its earthquakes like California, it might be worth considering—although it's worth noting that only 13% of California residents have earthquake insurance. Learn more about earthquake insurance in this article. Kiplinger Earth is constantly bombarded by material from spaceMost 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. 1440 Roughly 25,000 workers died building the canalFor each mile of canal that was built, 500 workers lost their lives. The threats came from multiple fronts: mudslides, floods, earthquakes and disease-carrying mosquitoes. Workplace accidents became so common that artificial limb manufacturers competed for contracts with the canal builders. History Disposal wells for fracking wastewater have been linked to spikes in seismic activityA study of all such underground wells in the central and eastern US found that they were 1.5 times more likely to be associated with earthquakes than oil recovery wells. The link between fluid injection and earthquakes was strongest at disposal wells where fluid was injected quickly. Science Machu Picchu, 101Machu Picchu was built right on top of two intersecting fault lines, which makes it even more baffling how its temples and terraces have survived for more than 500 years—especially since no mortar was used to hold the precisely cut stones together. As this three-minute NatGeo video explains, this ingenious construction method allows the stones to bounce in place when earthquakes hit, shaking and rattling but rarely collapsing. National Geographic Society 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... Cornell University How the Turkish earthquake created a 100-mile ruptureA 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... Reuters How did the Inca build Machu Picchu?How did the Inca, a people without iron or steel, build a city that has withstood hundreds of years of earthquakes and inclement weather? Machu Picchu stands atop steep landslide prone slopes and active fault lines and gets up to 80 inches of rain... Discover Variations in rock types contribute to uncertainty in earthquake predictionsDifferent rock types can withstand different amounts of stress before breaking and melt at different temperatures within Earth’s interior, preventing uniform modeling. The planet’s uneven mass distribution also creates variations in gravitational force, complicating mantle movement. YouTube How we know what’s deep inside the Earth, despite never traveling thereWe'll likely never see the Earth's core, but we can make educated guesses about what it's like down there. Nearly as hot as the sun's surface and under impossibly high pressure, the inner Earths extreme conditions make it impossible to explore. Yet, seismic waves during earthquakes, volcanic eruptions, and light waves from the sun provide fascinating insights about our planet’s mantle, crust, and core. Discover Magazine 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. The New Yorker Reimagine damaged cultural sites from around the worldNeoMam art studios created animated GIFs restoring six endangered World Heritage sites to their original glory. These include Hatra, a fortified city in Iraq, and Nan Madol, an island site in the northwest Pacific. These landmarks are designated as at risk due to threats like earthquakes and conflict in the regions. Enjoy some of the beautifully restored landmarks with this brief article. Colossal

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