The 8-km-high volcano Maat Mons is displayed in this perspective view of the surface of Venus, with the vertical scale multiplied by 22. Maat Mons is the highest volcano on the Planet Venus. The Volcano is above the mean planetary radius and is found at 0 5. Based on Magellan probe radar images. The Magellan spacecraft was a space probe sent to the planet Venus, the first post- Voyager unmanned spacecraft to be launched by NASA

The surface of Venus is dominated by volcanism and has produced more volcanoes than any other planet in the solar system. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Plate tectonics and hotspots Divergent plate boundaries At the A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is The Solar System consists of the Sun and those celestial objects bound to it by Gravity. It has a surface that is 90% basalt, and about 80% of the planet consists of a mosaic of volcanic lava plains, indicating that volcanism played a major role in shaping its surface. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures The planet may have had a major global resurfacing event about 500 million years ago,^[1] from what scientists can tell from the density of impact craters on the surface. Even though there are over 1,600 major volcanoes on Venus, none is known to be erupting at present and most are probably long extinct. ^[2] However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank. Radar is a system that uses electromagnetic waves to identify the range altitude direction or speed of both moving and fixed objects such as Aircraft, ships The Magellan spacecraft was a space probe sent to the planet Venus, the first post- Voyager unmanned spacecraft to be launched by NASA The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Maat Mons is the highest volcano on the Planet Venus. The Volcano is above the mean planetary radius and is found at 0 Volcanic ash consists of small Tephra, which are bits of pulverized rock and glass created by volcanic eruptions less than in diameter

Although many lines of evidence suggest that Venus is likely to be volcanically active, present-day eruptions at Maat Mons have not been confirmed.

Venus contains shield volcanoes, widespread lava flows and some unusual volcanoes called pancake domes and "tick-like" structures which are not present on Earth. A shield volcano is a large Volcano with shallow-sloping sides Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures A pancake dome is an unusual type of Volcano found on the planet Venus. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Pancake dome volcanoes are up to 15 kilometers (9 mi) in diameter and less than 1 kilometer (0. 6 mi) in height and are 100 times larger than those formed on Earth. They are usually associated with coronae and tesserae (large regions of highly deformed terrain, folded and fractured in two or three dimensions, believed to be unique to Venus). The pancakes are thought to be formed by highly viscous, silica-rich lava erupting under Venus's high atmospheric pressure. The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide

The "tick-like" structures are called scalloped margin domes. A scalloped margin dome is a volcanic dome that has experienced collapse and Mass wasting such as landslides on its perimeter They are commonly called ticks because they appear as domes with numerous legs. They are thought to have undergone mass wasting events such as landslides on their margins. Sometimes deposits of debris can be seen scattered around them.

Radar mosaic of two 65-km-wide (and less than 1-km-high) pancake domes in Venus's Eistla region. A pancake dome is an unusual type of Volcano found on the planet Venus.

On Earth, volcanoes are mainly of two types: shield volcanoes and composite or stratovolcanoes. A shield volcano is a large Volcano with shallow-sloping sides A stratovolcano, also called a composite volcano is a tall conical Volcano composed of many layers of hardened Lava, Tephra, and Volcanic The shield volcanoes, for example those in Hawaii, eject magma from the depths of the Earth in zones called hot spots. The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet In Geology, a hotspot is a location on the Earth's surface that has experienced active volcanism for a long period of time The lava from these volcanos is relatively fluid and permits the escape of gases. Composite volcanos, such as Mount Saint Helens and Mount Pinatubo, are associated with tectonic plates. Mount St Helens is an active Stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States Mount Pinatubo is an active Stratovolcano located on the island of Luzon In this type of volcano, the oceanic crust of one plate is sliding underneath the other in a subduction zone, together with an inflow of seawater, producing a gummier lava that restricts the exit of the gases, and for that reason, composite volcanoes tend to erupt more violently. Oceanic crust is the part of Earth's Lithosphere that surfaces in the Ocean basins In Geology, a subduction zone is an area on Earth where two tectonic plates meet and move towards one another with one sliding underneath the other

On Venus, where there are no tectonic plates or seawater, volcanoes are of the shield type. Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere Seawater is Water from a Sea or Ocean. On average seawater in the world's oceans has a Salinity of about 3 Nevertheless, the morphology of the volcanos of Venus is different: on the Earth, shield volcanoes can be a few tens of kilometres wide and up to 10 kilometres high (6. 2 mi) in the case of Mauna Kea, measured from the sea floor. Mauna Kea is a Dormant volcano in the Hawaiian Islands, one of five volcanoes which together form the Island of Hawaii. On Venus, these volcanos can cover hundreds of kilometres in area, but they are relatively flat, with an average height of 1. 5 kilometres (0. 9 mi).

Computer-generated perspective view of pancake domes in Venus's Alpha Regio. Alpha Regio is a region of the planet Venus extending for about 1500 kilometers centered at 22°S 5°E

Other unique features of Venus's surface are novae (radial networks of dikes or grabens) and arachnoids. A dike or dyke in Geology is a type of Sheet intrusion referring to any geologic body that cuts Discordantly ' across planar A graben is a depressed block of land bordered by parallel faults Graben is German for ditch. In Astrogeology, an arachnoid is a large structure of unknown origin and they have been found only on the surface of the Planet Venus. A nova is formed when large quantities of magma are extruded onto the surface to form radiating ridges and trenches which are highly reflective to radar. These dikes form a symmetrical network around the central point where the lava emerged, where there may also be a depression caused by the collapse of the magma chamber. A magma chamber is a large underground pool of molten rock lying under the surface of the earth's crust

Arachnoids are so named because they resemble a spider's web, featuring several concentric ovals surrounded by a complex network of radial fractures similar to those of a nova. It is not known whether the 250 or so features identified as arachnoids actually share a common origin, or are the result of different geological processes

Arachnoid surface feature on Venus

See also

• Volcanism on Io

References