Portal:Earth sciences
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The Earth Sciences Portal
Earth seen from Moon
Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres: the biosphere, hydrosphere/cryosphere, atmosphere, and geosphere (or lithosphere). Earth science can be considered to be a branch of planetary science but with a much older history. (Full article...)
Selected articles
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Yellowstone National Park is a national park of the United States located in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the 42nd U.S. Congress through the Yellowstone National Park Protection Act and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first national park in the U.S. and is also widely held to be the first national park in the world. The park is known for its wildlife and its many geothermal features, especially the Old Faithful geyser, one of its most popular. While it represents many types of biomes, the subalpine forest is the most abundant. It is part of the South Central Rockies forests ecoregion.
While Native Americans have lived in the Yellowstone region for at least 11,000 years, aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the park originally fell under the jurisdiction of the U.S. Department of the Interior, the first Secretary of the Interior to supervise the park being Columbus Delano. However, the U.S. Army was eventually commissioned to oversee the management of Yellowstone for 30 years between 1886 and 1916. In 1917, the administration of the park was transferred to the National Park Service, which had been created the previous year. Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than a thousand indigenous archaeological sites. (Full article...) -
Archaeopteryx (/ˌɑːrkiːˈɒptərɪks/; lit. 'old-wing'), sometimes referred to by its German name, "Urvogel" (lit. Primeval Bird) is a genus of bird-like dinosaurs. The name derives from the ancient Greek ἀρχαῖος (archaīos), meaning "ancient", and πτέρυξ (ptéryx), meaning "feather" or "wing". Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest known bird (member of the group Avialae). Older potential avialans have since been identified, including Anchiornis, Xiaotingia, and Aurornis.
Archaeopteryx lived in the Late Jurassic around 150 million years ago, in what is now southern Germany, during a time when Europe was an archipelago of islands in a shallow warm tropical sea, much closer to the equator than it is now. Similar in size to a Eurasian magpie, with the largest individuals possibly attaining the size of a raven, the largest species of Archaeopteryx could grow to about 0.5 m (1 ft 8 in) in length. Despite their small size, broad wings, and inferred ability to fly or glide, Archaeopteryx had more in common with other small Mesozoic dinosaurs than with modern birds. In particular, they shared the following features with the dromaeosaurids and troodontids: jaws with sharp teeth, three fingers with claws, a long bony tail, hyperextensible second toes ("killing claw"), feathers (which also suggest warm-bloodedness), and various features of the skeleton. (Full article...) -
The tornado outbreak of April 6–8, 2006, was a major tornado outbreak in the central and parts of the southern United States that began on April 6, 2006, in the Great Plains and continued until April 8 in South Carolina, with most of the activity on April 7. The hardest-hit region was Middle Tennessee, where several strong tornadoes devastated entire neighborhoods and left ten people dead. Some of the worst damage took place in Gallatin, Tennessee, and other communities north of Nashville also sustained significant damage.
There were 73 tornadoes confirmed across 13 states, with the bulk of them coming on the afternoon and evening of April 7 across the South, particularly in Tennessee. In total, 10 deaths were reported as a result of the tornadoes, and over $650 million in damage was reported, of which over $630 million was in Middle Tennessee. It was the third major outbreak of 2006, occurring just days after another major outbreak on April 2. It was also considered by some to be the worst disaster event in Middle Tennessee since the 1998 tornado outbreak. (Full article...) -
Yosemite National Park (/joʊˈsɛmɪti/ yoh-SEM-ih-tee) is a national park of the United States in California. It is bordered on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers 759,620 acres (1,187 sq mi; 3,074 km2) in four counties – centered in Tuolumne and Mariposa, extending north and east to Mono and south to Madera. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its granite cliffs, waterfalls, clear streams, groves of giant sequoia, lakes, mountains, meadows, glaciers, and biological diversity. Almost 95 percent of the park is designated wilderness. Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada.
Its geology is characterized by granite and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and tilted to form its unique slopes, which increased the steepness of stream and river beds, forming deep, narrow canyons. About one million years ago glaciers formed at higher elevations. They moved downslope, cutting and sculpting the U-shaped Yosemite Valley. (Full article...) -
Hurricane Gloria was a powerful tropical cyclone that caused significant damage along the East Coast of the United States and in Atlantic Canada during the 1985 Atlantic hurricane season. It was the first significant tropical cyclone to strike the northeastern United States since Hurricane Agnes in 1972 and the first major storm to affect New York City and Long Island directly since Hurricane Donna in 1960. Gloria was a Cape Verde hurricane originating from a tropical wave on September 16 in the eastern Atlantic Ocean. After remaining a weak tropical cyclone for several days, Gloria intensified into a hurricane on September 22 north of the Lesser Antilles. During that time, the storm had moved generally westward, although it turned to the northwest due to a weakening of the ridge. Gloria quickly intensified on September 24, and the next day reached peak winds of 145 mph (233 km/h). The hurricane weakened before striking the Outer Banks of North Carolina on September 27. Later that day, Gloria made two subsequent landfalls on Long Island and across the coastline of western Connecticut, before becoming extratropical on September 28 over New England. The remnants moved through Atlantic Canada and went on to impact Western Europe, eventually dissipating on October 4.
Before Gloria made landfall, the National Hurricane Center issued hurricane warnings at some point for the East Coast of the United States from South Carolina to Maine. Hundreds of thousands of people evacuated, and the hurricane was described as the "storm of the century." In general, Gloria's strongest winds remained east of the center, which largely spared locations from North Carolina to New Jersey, and the passage at low tide reduced storm surge. Hurricane-force winds and gusts affected much of the path, which knocked down trees and power lines. This left over 4 million people without power, causing the worst power outage in Connecticut history related to a natural disaster. Fallen trees caused six of the storm's fourteen deaths. (Full article...) -
Mary Anning (21 May 1799 – 9 March 1847) was an English fossil collector, dealer, and palaeontologist. She became known internationally for her discoveries in Jurassic marine fossil beds in the cliffs along the English Channel at Lyme Regis in the county of Dorset, Southwest England. Anning's findings contributed to changes in scientific thinking about prehistoric life and the history of the Earth.
Anning searched for fossils in the area's Blue Lias and Charmouth Mudstone cliffs, particularly during the winter months when landslides exposed new fossils that had to be collected quickly before they were lost to the sea. Her discoveries included the first correctly identified ichthyosaur skeleton when she was twelve years old; the first two nearly complete plesiosaur skeletons; the first pterosaur skeleton located outside Germany; and fish fossils. Her observations played a key role in the discovery that coprolites, known as bezoar stones at the time, were fossilised faeces, and she also discovered that belemnite fossils contained fossilised ink sacs like those of modern cephalopods. (Full article...) -
Charles Robert Darwin (/ˈdɑːrwɪn/ DAR-win; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint presentation with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey.
Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped to investigate marine invertebrates. His studies at the University of Cambridge's Christ's College from 1828 to 1831 encouraged his passion for natural science. However, it was his five-year voyage on HMS Beagle from 1831 to 1836 that truly established Darwin as an eminent geologist. The observations and theories he developed during his voyage supported Charles Lyell's concept of gradual geological change. Publication of his journal of the voyage made Darwin famous as a popular author. (Full article...) -
Eruptions in the Lassen volcanic area in the last 70,000 years. Circle shows base of Mount Tehama. See timeline image.
The Lassen volcanic area presents a geological record of sedimentation and volcanic activity in and around Lassen Volcanic National Park in Northern California, U.S. The park is located in the southernmost part of the Cascade Mountain Range in the Pacific Northwest region of the United States. Pacific Oceanic tectonic plates have plunged below the North American Plate in this part of North America for hundreds of millions of years. Heat and molten rock from these subducting plates has fed scores of volcanoes in California, Oregon, Washington and British Columbia over at least the past 30 million years, including these in the Lassen volcanic areas.
Between 3 and 4 million years ago, volcanic-derived mud flows called lahars streamed down several major mountains that included nearby but now extinct Mount Yana and Mount Maidu to become the Tuscan Formation. Basaltic and later andesitic to dacitic flows of lava covered increasingly larger areas of this formation to eventually form the lava plateau upon which the park is situated. About 600,000 years ago, Mount Tehama started to rise as a stratovolcano in the southwestern corner of the park, eventually reaching an estimated 11,000 ft (3,400 m) in height. (Full article...) -
Bryce Canyon National Park (/braɪs/) is a national park of the United States located in southwestern Utah. The major feature of the park is Bryce Canyon, which despite its name, is not a canyon, but a collection of giant natural amphitheaters along the eastern side of the Paunsaugunt Plateau. Bryce is distinctive due to geological structures called hoodoos, formed by frost weathering and stream erosion of the river and lake bed sedimentary rock. The red, orange, and white colors of the rocks provide spectacular views for park visitors. Bryce Canyon National Park is much smaller and sits at a much higher elevation than nearby Zion National Park. The rim at Bryce varies from 8,000 to 9,000 feet (2,400 to 2,700 m).
The area is in portions of Garfield County and Kane County. (Full article...) -
Life in the Ediacaran Period as imagined by researchers in 1980.
The Ediacaran (/ˌiːdiˈækərən/; formerly Vendian) biota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (c. 635–538.8 Mya). These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.
The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, 575 million years ago. This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominated the Ediacaran fossil record, although relationships are still a matter of debate. (Full article...) -
Geologic time shown in a diagram called a geological clock, showing the relative lengths of the eons of Earth's history and noting major events
The geological history of the Earth follows the major geological events in Earth's past based on the geological time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.
Initially, Earth was molten due to extreme volcanism and frequent collisions with other bodies. Eventually, the outer layer of the planet cooled to form a solid crust when water began accumulating in the atmosphere. The Moon formed soon afterwards, possibly as a result of the impact of a planetoid with the Earth. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered from asteroids, produced the oceans. However, in 2020, researchers reported that sufficient water to fill the oceans may have always been on the Earth since the beginning of the planet's formation. (Full article...) -
The retreat of glaciers since 1850 is a well-documented effect of climate change. The retreat of mountain glaciers provide evidence for the rise in global temperatures since the late 19th century. Examples include mountain glaciers in western North America, Asia, the Alps in central Europe, and tropical and subtropical regions of South America and Africa. Since glacial mass is affected by long-term climatic changes, e.g. precipitation, mean temperature, and cloud cover, glacial mass changes are one of the most sensitive indicators of climate change. The retreat of glaciers is also a major reason for sea level rise. Excluding peripheral glaciers of ice sheets, the total cumulated global glacial losses over the 26 years from 1993 to 2018 were likely 5500 gigatons, or 210 gigatons per year.
On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions. Glaciers also exist in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand. Glacial bodies larger than 50,000 km2 (19,000 sq mi) are called ice sheets. They are several kilometers deep and obscure the underlying topography. (Full article...) -
Changes in surface air temperature over the past 50 years. The Arctic has warmed the most, and temperatures on land have generally increased more than sea surface temperatures.
Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global temperatures is driven by human activities, especially fossil fuel burning since the Industrial Revolution. Fossil fuel use, deforestation, and some agricultural and industrial practices release greenhouse gases. These gases absorb some of the heat that the Earth radiates after it warms from sunlight, warming the lower atmosphere. Carbon dioxide, the primary greenhouse gas driving global warming, has grown by about 50% and is at levels not seen for millions of years.
Climate change has an increasingly large impact on the environment. Deserts are expanding, while heat waves and wildfires are becoming more common. Amplified warming in the Arctic has contributed to thawing permafrost, retreat of glaciers and sea ice decline. Higher temperatures are also causing more intense storms, droughts, and other weather extremes. Rapid environmental change in mountains, coral reefs, and the Arctic is forcing many species to relocate or become extinct. Even if efforts to minimize future warming are successful, some effects will continue for centuries. These include ocean heating, ocean acidification and sea level rise. (Full article...) -
Ice core sample taken from drill
An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ice formed over a range of years. Cores are drilled with hand augers (for shallow holes) or powered drills; they can reach depths of over two miles (3.2 km), and contain ice up to 800,000 years old.
The physical properties of the ice and of material trapped in it can be used to reconstruct the climate over the age range of the core. The proportions of different oxygen and hydrogen isotopes provide information about ancient temperatures, and the air trapped in tiny bubbles can be analysed to determine the level of atmospheric gases such as carbon dioxide. Since heat flow in a large ice sheet is very slow, the borehole temperature is another indicator of temperature in the past. These data can be combined to find the climate model that best fits all the available data. (Full article...) -
The 1867 Manhattan earthquake struck Riley County, Kansas, in the United States on April 24, 1867, at 20:22 UTC, or about 14:30 local time. The strongest earthquake to originate in the state, it measured 5.1 on a seismic scale that is based on an isoseismal map or the event's felt area. The earthquake's epicenter was near the town of Manhattan.
The earthquake had a maximum perceived intensity of VII (Very strong) on the Mercalli intensity scale. It caused minor damage, reports of which were confined to Kansas, Iowa, and Missouri, according to the United States Geological Survey. Felt over an area of 200,000 square miles (520,000 km2), the earthquake reached the states of Indiana, Illinois, and possibly Ohio, though the latter reports have been questioned. (Full article...) -
Amchitka (/æmˈtʃɪtkə/; Aleut: Amchixtax̂;[page needed]) is a volcanic, tectonically unstable and uninhabited
island in the Rat Islands group of the Aleutian Islands in southwest Alaska. It is part of the Alaska Maritime National Wildlife Refuge. The island, with a land area of roughly 116 square miles (300 km2), is about 42 miles (68 km) long and 1 to 4 miles (1.6 to 6.4 km) wide. The area has a maritime climate, with many storms, and mostly overcast skies.
Amchitka was populated for more than 2,500 years by the Aleut people, but has had no permanent population since 1832. The island has been part of the United States since the Alaska Purchase of 1867. During World War II, it was used as an airfield by US forces in the Aleutian Islands Campaign. (Full article...) -
Earth is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere. Most of Earth's land is at least somewhat humid and covered by vegetation, while large sheets of ice at Earth's polar deserts retain more water than Earth's groundwater, lakes, rivers and atmospheric water combined. Earth's crust consists of slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth has a liquid outer core that generates a magnetosphere capable of deflecting most of the destructive solar winds and cosmic radiation.
Earth has a dynamic atmosphere, which sustains Earth's surface conditions and protects it from most meteoroids and UV-light at entry. It has a composition of primarily nitrogen and oxygen. Water vapor is widely present in the atmosphere, forming clouds that cover most of the planet. The water vapor acts as a greenhouse gas and, together with other greenhouse gases in the atmosphere, particularly carbon dioxide (CO2), creates the conditions for both liquid surface water and water vapor to persist via the capturing of energy from the Sun's light. This process maintains the current average surface temperature of 14.76 °C (58.57 °F), at which water is liquid under normal atmospheric pressure. Differences in the amount of captured energy between geographic regions (as with the equatorial region receiving more sunlight than the polar regions) drive atmospheric and ocean currents, producing a global climate system with different climate regions, and a range of weather phenomena such as precipitation, allowing components such as nitrogen to cycle. (Full article...) -
A scene in Uttarakhand's Valley of Flowers National Park. In contrast to the rain shadow region of Tirunelveli, the park receives ample orographic precipitation due to its location in a mountainous windward-facing region wedged between the Zanskars and the Greater Himalayas.
The climate of India consists of a wide range of weather conditions across a vast geographic scale and varied topography. Based on the Köppen system, India encompasses a diverse array of climatic subtypes. These range from arid and semi-arid regions in the west to highland, sub-arctic, tundra, and ice cap climates in the northern Himalayan regions, varying with elevation. The northern lowlands experience subtropical conditions, with some areas at higher altitudes, like Srinagar, touching continental climates. In contrast, much of the south and the east exhibit tropical climate conditions, which support lush rainforests in these territories. Many regions have starkly different microclimates, making it one of the most climatically diverse countries in the world. The country's meteorological department follows the international standard of four seasons with some local adjustments: winter (December to January),spring(February to March),summer (April to June), South West monsoon (July to September) and North-east monsoon or autumn (October and November).
India's geography and geology are climatically pivotal: the Thar Desert in the northwest and the Himalayas in the north work in tandem to create a culturally and economically important monsoonal regime. As Earth's highest and most massive mountain range, the Himalayas bar the influx of frigid katabatic winds from the icy Tibetan Plateau and northerly Central Asia. Most of North India is thus kept warm or is only mildly chilly or cold during winter; the same thermal dam keeps most regions in India hot in summer. The climate in South India is generally warmer, and more humid due to its coastlines. However some hill stations in South India such as Ooty are well known for their cold climate. (Full article...) -
The 1949 Ambato earthquake was the deadliest earthquake in the Western Hemisphere in five years. On August 5, 1949, it struck Ecuador's Tungurahua Province southeast of its capital Ambato and killed 5,050 people. Measuring 6.4 on the Ms scale, it originated from a hypocenter 15 km beneath the surface. The nearby villages of Guano, Patate, Pelileo, and Pillaro were destroyed, and the city of Ambato suffered heavy damage. The earthquake flattened buildings and subsequent landslides caused damage throughout the Tungurahua, Chimborazo, and Cotopaxi Provinces. It disrupted water mains and communication lines and opened a fissure into which the small town of Libertad sank. Moderate shaking from the event extended as far away as Quito and Guayaquil.
Earthquakes in Ecuador stem from two major interrelated tectonic areas: the subduction of the Nazca plate under the South American plate and the Andean Volcanic Belt. The 1949 Ambato earthquake initially followed an intersection of several northwest–southeast-trending faults in the Inter-Andean Valley which were created by the subduction of the Carnegie Ridge. Strata of rock cracked as the earthquake ruptured the faults, sending out powerful shock waves. Today threats exist throughout the country from both interplate and intraplate seismicity. (Full article...) -
The ACFEL ice auger showing an ice core pushed up into the core remover barrel.
Ice drilling allows scientists studying glaciers and ice sheets to gain access to what is beneath the ice, to take measurements along the interior of the ice, and to retrieve samples. Instruments can be placed in the drilled holes to record temperature, pressure, speed, direction of movement, and for other scientific research, such as neutrino detection.
Many different methods have been used since 1840, when the first scientific ice drilling expedition attempted to drill through the Unteraargletscher in the Alps. Two early methods were percussion, in which the ice is fractured and pulverized, and rotary drilling, a method often used in mineral exploration for rock drilling. In the 1940s, thermal drills began to be used; these drills melt the ice by heating the drill. Drills that use jets of hot water or steam to bore through ice soon followed. A growing interest in ice cores, used for palaeoclimatological research, led to ice coring drills being developed in the 1950s and 1960s, and there are now many different coring drills in use. For obtaining ice cores from deep holes, most investigators use cable-suspended electromechanical drills, which use an armoured cable to carry electrical power to a mechanical drill at the bottom of the borehole. (Full article...) -
The Ediacaran ( /ˌiːdiˈækərən, ˌɛdi-/ EE-dee-AK-ər-ən, ED-ee-) is a geological period of the Neoproterozoic Era that spans 96 million years from the end of the Cryogenian Period at 635 Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last period of the Proterozoic Eon as well as the last of the so-called "Precambrian supereon", before the beginning of the subsequent Cambrian Period marks the start of the Phanerozoic Eon, where recognizable fossil evidence of life becomes common.
The Ediacaran Period is named after the Ediacara Hills of South Australia, where trace fossils of a diverse community of previously unrecognized lifeforms (later named the Ediacaran biota) were first discovered by geologist Reg Sprigg in 1946. Its status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. Although the period took namesake from the Ediacara Hills in the Nilpena Ediacara National Park, the type section is actually located in the bed of the Enorama Creek within the Brachina Gorge in the Ikara-Flinders Ranges National Park, at , approximately 55 km (34 mi) southeast of the Ediacara Hills fossil site. (Full article...) -
Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8·4H2O. It is rare and valuable in finer grades and has been prized as a gemstone for millennia due to its hue.
Like most other opaque gems, turquoise has been devalued by the introduction of treatments, imitations, and synthetics into the market. The robin egg blue or sky blue color of the Persian turquoise mined near the modern city of Nishapur, Iran, has been used as a guiding reference for evaluating turquoise quality. (Full article...) -
Hurricane Lili was the second costliest, deadliest, and strongest hurricane of the 2002 Atlantic hurricane season, only surpassed by Hurricane Isidore, which affected the same areas around a week before Lili. Lili was the twelfth named storm, fourth hurricane, and second major hurricane of the 2002 Atlantic hurricane season. The storm developed from a tropical disturbance in the open Atlantic on September 21. It continued westward, affecting the Lesser Antilles as a tropical storm, then entered the Caribbean. As it moved west, the storm dissipated while being affected by wind shear south of Cuba, and regenerated when the vertical wind shear weakened. It turned to the northwest and strengthened up to category 2 strength on October 1. Lili made two landfalls in western Cuba later that day, and then entered the Gulf of Mexico. The hurricane rapidly strengthened on October 2, reaching Category 4 strength that afternoon. It weakened rapidly thereafter, and hit Louisiana as a Category 1 hurricane on October 3. It moved inland and dissipated on October 6.
Lili caused extensive damage through the Caribbean, particularly to crops and poorly built homes. Mudslides were common on the more mountainous islands, particularly Haiti and Jamaica. In the United States, the storm cut off the production of oil within the Gulf of Mexico, and caused severe damage in parts of Louisiana. Lili was also responsible for severe damage to the barrier islands and marshes in the southern portion of the state. Total damage amounted to $925 million (2002 USD), and the storm killed 15 people during its existence. (Full article...) -
In 1257, a catastrophic eruption occurred at Samalas, a volcano on the Indonesian island of Lombok. The event had a probable Volcanic Explosivity Index of 7, making it one of the largest volcanic eruptions during the Holocene epoch. It left behind a large caldera that contains Lake Segara Anak. Later volcanic activity created more volcanic centres in the caldera, including the Barujari cone, which remains active.
The event created eruption columns reaching tens of kilometres into the atmosphere and pyroclastic flows that buried much of Lombok and crossed the sea to reach the neighbouring island of Sumbawa. The flows destroyed human habitations, including the city of Pamatan, which was the capital of a kingdom on Lombok. Ash from the eruption fell as far as 340 kilometres (210 mi) away in Java; the volcano deposited more than 10 cubic kilometres (2.4 cu mi) of rocks and ash. (Full article...) -
Map of Earth's 16 principal tectonic plates
Divergent:Extension zoneConvergent:Collision zoneTransform:Sinistral transform
Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called tectonics.
Tectonic plates also occur in other planets and moons.
Earth's lithosphere, the rigid outer shell of the planet including the crust and upper mantle, is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault): convergent, divergent, or transform. The relative movement of the plates typically ranges from zero to 10 cm annually. Faults tend to be geologically active, experiencing earthquakes, volcanic activity, mountain-building, and oceanic trench formation. (Full article...)
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Did you know (auto-generated)
- ... that English amateur geologist Charlotte Eyton wrote a number of papers and pamphlets on the geology of the Wrekin, a part of Shropshire, between 1862 and 1870?
- ... that the Apollo 12 Solar Wind Spectrometer detected a gas-ion shockwave produced by the impact of the Apollo 13 S-IVB stage on the lunar surface?
- ... that geologist Gilbert Wilson was the fifth Wilson at school, so he was known as "Quintus"?
- ... that Frederick Murray Trotter had a distinguished career as a field geologist despite losing a part of his skull and an eye to shrapnel during World War I?
- ... that life exists in every part of the biosphere, from the deepest parts of the ocean to altitudes of up to 64 km (40 miles) in the atmosphere?
- ... that the Iowa Colored Cowboys played softball for audiences of over a thousand people, in an atmosphere similar to a Harlem Globetrotters show?
- ... that the geology of the Ellsworth Mountains was explored by geologists using motor toboggans in 1961?
- ... that the Danish geologist Tove Birkelund received a gold medal for her early work on fossils of Scaphites in Greenland?
More did you know? -
- ... that New Zealand geologist Patrick Marshall (pictured) was the first who used the term "andesite line"?
- ...that the Earth's magnetic field is shaped roughly as a magnetic dipole, with the poles currently located proximate to the planet's geographic poles?
- ...In total, about 401 people have been outside the Earth's atmosphere as of 2004, and, of these, twelve have walked on the Moon?
- ...that the Apache-Sitgreaves National Forest is a 2 million acre (8000 km²) national forest which runs along the Mogollon Rim and the White Mountains in east-central Arizona and extending into New Mexico, United States?
- ...that the Himalaya mountain range is the world's highest mountain range?
- ... that the 1999 Chamoli earthquake in India, in which 103 people died, was also felt in the Baitadi, Dadeldhura and Kanchanpur districts in Nepal?
Related portals
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The world's largest compass rose, drawn on the desert floor at Edwards Air Force Base in California, United States. Painted on the playa near Dryden Flight Research Center, it is inclined to magnetic north and is used by pilots for calibrating heading indicators. (Credit: NASA.) (from Portal:Earth sciences/Selected pictures) -
Incandescent Pahoeoe Fountain at Shield volcano, by J.D. Griggs, USGS (from Wikipedia:Featured pictures/Sciences/Geology) -
A 2002 eruption of Mount Etna, a volcano on the Italian island of Sicily, viewed from the International Space Station. (Credit: NASA, with image edits by User:Darkone.) (from Portal:Earth sciences/Selected pictures) -
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Pressure release of granite in the Enchanted Rock State Natural Area of Texas, United States. The photo shows the geological exfoliation of granite dome rock. (Taken by Wing-Chi Poon on 2nd April 2005.) (from Portal:Earth sciences/Selected pictures) -
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Weathered rocks at Joshua Tree National Park, by Mila Zinkova (from Wikipedia:Featured pictures/Sciences/Geology) -
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Atmospheric gases scatter blue wavelengths of visible light more than other wavelengths, giving the Earth’s visible edge a blue halo. At higher and higher altitudes, the atmosphere becomes so thin that it essentially ceases to exist. Gradually, the atmospheric halo fades into the blackness of space. (Credit: NASA's Earth Observatory.) (from Portal:Earth sciences/Selected pictures) -
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Astronauts aboard the Space Shuttle Discovery recorded this rarely seen phenomenon of the full Moon partially obscured by the atmosphere of Earth. The image was recorded with an electronic still camera at 15:15:15 GMT, Dec. 21, 1999. (Credit: NASA.) (from Portal:Earth sciences/Selected pictures) -
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Ant trapped in Baltic amber, by Baltic-amber-beetle (edited by AmericanXplorer13) (from Wikipedia:Featured pictures/Sciences/Geology) -
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Erg Chebbi (Arabic: عرج شبّي) is the sole Saharan erg in Morocco. It is 22 km long (North-South) and 5 km wide. Its dunes reach a maximum height of 150 meters. It is located roughly 40 kilometers south-east of Erfoud. The local center for tourists is the village of Merzouga. (Credit: Rosa Cabecinhas and Alcino Cunha.) (from Portal:Earth sciences/Selected pictures) -
2004 Indian Ocean Earthquake tsunami at 2004 Indian Ocean earthquake and tsunami, by Vasily V. Titov, NOAA (edited by Veledan) (from Wikipedia:Featured pictures/Sciences/Geology) -
Antarctica, the continent surrounding the Earth's South Pole, is the coldest place on earth and is almost entirely covered by ice. Antarctica was discovered in late January 1820. Too cold and dry to support virtually any vascular plants, Antarctica's flora presently consists of around 250 lichens, 100 mosses, 25-30 liverworts, and around 700 terrestrial and aquatic algal species. (Credit: NASA.) (from Portal:Earth sciences/Selected pictures) -
Specimen from a palaeontological site of Lebanon at Paleontology in Lebanon, by Mila Zinkova (from Wikipedia:Featured pictures/Sciences/Geology) -
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Mount Hood reflected in Mirror Lake, Oregon. (Credit: Oregon's Mt. Hood Territory.) (from Portal:Earth sciences/Selected pictures) -
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A true-color picture of Ireland, as seen from space, with the Atlantic Ocean to the west and the Irish Sea to the east. (from Portal:Earth sciences/Selected pictures) -
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This map shows the tracks of all tropical cyclones that formed worldwide from 1985 to 2005. The points show the locations of the storms at six-hourly intervals and use the color scheme shown on the right from the Saffir-Simpson Hurricane Scale. (Credit: Nilfanion.) (from Portal:Earth sciences/Selected pictures) -
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A thunderstorm is a form of severe weather involving lightning and thunder. Thunderstorms have had a lasting and powerful influence on mankind. Romans thought them to be battles waged by Jupiter. Thunderstorms were associated with the Thunderbird, held by Native Americans to be a servant of the Great Spirit. (Credit: John Kerstholt.) (from Portal:Earth sciences/Selected pictures) -
Cirrus clouds are composed of ice crystals and shaped like hairlike filaments. They are formed at an altitudes above 5000 metres (16,500 feet). The streaks are made of snowflakes that are falling from the cloud and being caught by the high level winds. The streaks point in the direction of the wind and may appear straight giving the clouds the appearance of a comma (cirrus uncinus), or may by seem tangled, an indication of high level turbulence. (Credit: Piccolo Namek.) (from Portal:Earth sciences/Selected pictures) -
Oceans cover almost three quarters (71%) of the surface of the Earth, and nearly half of the world's marine waters are over 3000 m deep. This global, interconnected body of salt water, called the World Ocean, is divided by the continents and archipelagos into the following five bodies, from the largest to the smallest: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean. Official boundaries are defined by the International Hydrographic Organization. (Credit: Alexandre Van de Sande.) (from Portal:Earth sciences/Selected pictures) -
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Mount Redoubt eruption, by R. Clucas (USGS) (edited by Janke) (from Wikipedia:Featured pictures/Sciences/Geology) -
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Winter is one of the four seasons of temperate zones. Meteorological winter is the season having the shortest days (which vary greatly according to latitude) and the lowest temperatures. (Credit: Richard Fabi.) (from Portal:Earth sciences/Selected pictures) -
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Glacier retreat is a type of glacial motion in which more material ablates from its terminus of the glacier than is replenished by flow into that region. In this region of the Bhutan-Himalaya, glacial lakes have been rapidly forming on the surface of the debris-covered glaciers and researchers have found a strong correlation between increasing temperatures and glacial retreat. (Credit: NASA & USGS.) (from Portal:Earth sciences/Selected pictures) -
Blairmorite, by Paul Glombick (edited by Bammesk) (from Wikipedia:Featured pictures/Sciences/Geology) -
Northern shore meadows of Sihlsee, an artificial lake near Einsiedeln in the Canton of Schwyz, Switzerland. (Credit: Markus Bernet.) (from Portal:Earth sciences/Selected pictures) -
An October 2002 eruption of Mount Etna, a volcano on the Italian island of Sicily, as seen from the International Space Station. Etna is the largest of Italy's three active volcanoes and one of the most active in the whole entire world. This eruption, one of Etna's most vigorous in years, was triggered by a series of earthquakes. Ashfall was reported as far away as Libya, 600 km (373 mi) to the south. (Credit: Expedition 5 crew.) (from Portal:Earth sciences/Selected pictures) -
Hurricane Katrina was the third most powerful storm of the 2005 Atlantic hurricane season. It first made landfall as a Category 1 hurricane just north of Miami, Florida on August 25, 2005, then again on August 29 along the Central Gulf Coast near Buras-Triumph, Louisiana as a Category 4 storm. This photograph of the eye of the hurricane was taken from a NOAA Hurricane Hunter aircraft on August 28, 2005. (Credit: NOAA.) (from Portal:Earth sciences/Selected pictures) -
Petrified log at Petrified Forest National Park, by Moondigger (from Wikipedia:Featured pictures/Sciences/Geology) -
The Richat Structure is a depression in the country of Mauritania, almost 50 km (30 mi) across. It was originally thought to be the impact of a meteorite. Now it is thought to be a symmetrical uplift (circular anticline or dome) that has been exposed to erosion. In this false-color photo, bedrock is brown, sand is yellow and white, vegetation is green, and salty sediments are blue. (Credit: Landsat 7.) (from Portal:Earth sciences/Selected pictures) -
Satellite image of Cyclone Gafilo, a powerful Category 5 tropical cyclone which struck Madagascar in March 2004, causing devastating damage. This was taken just before landfall, when the system was at its peak intensity about 333 km (207 mi) east of Madagascar, with sustained windspeed of 260 km/h (160 mph). At least 250 people were listed dead, with more missing, and 300,000 people were left homeless due to Gafilo. (Credit: Terra satellite, NASA.) (from Portal:Earth sciences/Selected pictures) -
Crystalline dolomite and magnesite, by Didier Descouens (from Wikipedia:Featured pictures/Sciences/Geology) -
Tsunami in Thailand at 2004 Indian Ocean earthquake and tsunami, by David Rydevik (from Wikipedia:Featured pictures/Sciences/Geology) -
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In the news
- 7 January 2025 – 2025 Tibet earthquake
- At least 126 people are killed and dozens of others are injured when a magnitude Mw 7.1 (Ms 6.8) earthquake strikes Tingri County, Shigatse, Tibet Autonomous Region, China. (Al Jazeera) (AP)
- 3 January 2025 – 2024–25 Ethiopian earthquakes
- Evacuations are ordered in central Ethiopia due to increasing volcanic tremor and other unrest at the Mount Fentale stratovolcano, which last erupted in the 19th century. (Reuters)
- 3 January 2025 –
- Air quality technology company IQAir reports that Hanoi, Vietnam, has the worst air pollution of any city on Earth, with levels of hazardous small particles, known as PM2.5, measured at 266 micrograms per cubic metre. (Reuters)
- 25 December 2024 –
- A Turkish court sentences the owner and architect of the Grand Isias Hotel in Adıyaman to more than 18 years in prison for negligent homicide after 72 people died when the hotel collapsed in the 2023 earthquakes. (DW)
- 17 December 2024 – 2024 Port Vila earthquake
- A 7.4 magnitude earthquake strikes Vanuatu's capital Port Vila, with at least fourteen people killed and more than 200 others injured. (RNZ)
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