GroundwaterGroundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table.
EarthquakeSudden movement of the Earth's crustEarthquake epicenters occur mostly along tectonic plate boundaries, especially on the Pacific Ring of Fire.An earthquake, also called a quake, tremor, or temblor, is the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves.
SubsidenceSubsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope movement.
Water tableThe water table is the upper surface of the phreatic zone or zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with groundwater, which may be fresh, saline, or brackish, depending on the locality. It can also be simply explained as the depth below which the ground is saturated. The portion above the water table is the vadose zone.
GlacierPersistent body of ice that moves downhill under its own weightGlacier of the Geikie Plateau in GreenlandThe Taschachferner in the Ötztal Alps in Austria. The mountain to the left is the Wildspitze (3,768 m), the second highest in AustriaThe Baltoro Glacier in Pakistan. It is 62 kilometres (39 mi) long, the fifth longest alpine glacier in the world.A glacier (US: ; UK: or ) is a persistent body of natural ice, a form of rock, that is constantly moving under its own weight.
Ice sheetLarge mass of glacial iceOne of Earth's two ice sheets: The Antarctic ice sheet covers about 98% of the Antarcticcontinent and is the largest single mass of ice on Earth. It has an average thickness of over 2 kilometers.In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacialice that covers surrounding terrain and is greater than 50,000 km (19,000 sq mi). The two current ice sheets are the Antarctic ice sheet and the Greenland ice sheet.
InfrastructureInfrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and private physical structures such as roads, railways, bridges, airports, public transit systems, tunnels, water supply, sewers, electrical grids, and telecommunications (including Internet connectivity and broadband access).
Earth's crustEarth's crust is its outer shell of rock, comprising less than one percent of the planet's radius and volume. It is the top component of the lithosphere, a solidified division of Earth's layers that includes the crust and the upper part of the mantle. The lithosphere is broken into tectonic plates whose motion allows heat to escape the interior of Earth into space.
EarthThird planet from the SunSurface equivalent doserate0.274 μSv/hAbsolute magnitude (H)−3.99AtmosphereSurface pressure101.325 kPa (at sea level)Composition by volume78.084% nitrogen (dry air)20.946% oxygen (dry air)≤1% water vapor (variable)0.9340% argon0.0430% carbon dioxide0.00182% neon0.00052% helium0.00017% methane0.00011% krypton0.00006% hydrogen Source:Earth is the third planet from the Sun and the only astronomical object known to harbor life.
VolcanoRupture in a planet's crust where material escapesAugustine Volcano (Alaska) during its eruptive phase on January 24, 2006A volcano is a vent or fissure in the crust of a planetary-mass object that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater.
Fault (geology)In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes.
ValleyA valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a very long period. Some valleys are formed through erosion by glacial ice. These glaciers may remain present in valleys in high mountains or polar areas.
RainForm of precipitationHeavy rainfall on a roofRain or rainfall is a form of atmosphericprecipitation composed of droplets of wateraerosols that have condensed from atmospheric water vapor and fall by gravity. Depending on the intensity, rain can be described as a drizzle (very light, sporadic rainfall), a shower (brief, moderate rainfall), a cloudburst (brief heavy rainfall) or a downpour (prolonged heavy or "torrential" rainfall).*As an Amazon Associate I earn from qualifying purchases.