Volcanoes

• The study of the relief features of the Earth's crust is known as geomorphology
• diastrophism, large-scale deformation of Earth's crust by natural processes, which leads to the formation of continents and ocean basins, mountain systems, plateaus, rift valleys, and other features by mechanisms such as lithospheric plate movement (that is, plate tectonics), volcanic loading, or folding.
• The physical removal of rock or the wearing down of landmasses by geomorphic agents such as running water, glacial ice, and the winds referred to as erosion
• Weathering is the process by which rocks and other materials that are exposed to the Earth's surface and come into contact with the atmosphere decompose.
• Vulcanism, also known as volcanicity, refers to a variety of processes associated with the surface discharge of magma or hot water and steams, such as volcanoes, geysers, fumaroles, and hot springs. All of these processes are fueled by the underground's powerful heat source.
• A volcano is an opening on the earth’s surface through which molten material from beneath the earth can escape.
• geyser is a surface vent that periodically ejects a column of hot water and steam.
• hot spring, also called a thermal spring is a source of geothermally heated water rising to the surface of the Earth's crust.
• More than 75% of volcanos are located at circle of fire also known as the ring of fire
• Cone - the most striking part of the volcano, usually composed of mixtures of lava and pyroclastic material. Viscous and slow-moving granitic magna forms high-sided steep cones, while fast-moving basaltic magma creates low to almost flat cones.
• Vent -the opening through which an eruption takes place. This main part of a volcano supplies the magma from the underlying source to the top of the volcano. They can be straight or convoluted
• Magma chamber -the large underground pool of liquid rock found beneath the Earth's crust.
• Crater -a basin-like depression over a vent at the summit of the cone
• Caldera -a volcanic depression much larger than the original crater
• Lava- the rock or magma expelled from a volcano during an eruption. Its temperature upon ejection can reach up to 700°C, hence it flows until it cools and hardens.
• Dikes -the barrier or obstacles in a volcano. Dikes are found in igneous forms that, under great pressure, cut fractures or fissures across previously formed metamorphic, sedimentary, or igneous rocks.
• Sills -otherwise known as intrusive sheets; they are solidified lava flows that originally forced their way between and parallel to older layers of rocks.
• Conduit -a channel or pipe conveying liquid materials such as magma
• Flank -the side of a volcano
• Summit -the highest point or apex of a volcano
• Throat -the entrance of a volcano
• Ash cloud -expelled into the atmosphere; volcanic ash or ash cloud is composed of pulverized rock and glass created during the eruption
• Volcanic bombs the chunks of lava blasted into the air that solidify before reaching the ground. Their sizes may vary and can measure up to 64 mm in diameter.
• Pyroclastic flow -fast-moving currents of hot gases and rock traveling downhill from a volcano The gases can reach temperatures of more than 1000°C and can move up to a speed of 700 km/ hr. This includes pumice flow, ash flow, block and ash flow, glowing and erupting clouds called nuée ardente, and avalanche. In terms of size, particles with less than 2 mm in diameter are called ashes; those with 2-64 mm in diameter are called lapilli; while those bigger than 64 mm in diameter are called blocks and bombs
• Tephra fall -refers to fragmented material that consists of pumice, scoria, lithic materials, crystals, or a combination of the four
• Lahar -also called mudflows; they are a flowing mixture of volcanic debris and water. They are classified as primary or hot when associated with a volcanic eruption, or as cold lahar when they are caused by heavy rainfall.