MY OWN KIND OF SPACE

                                                                   
                                                             VOLCANO

                          

 Volcanoes are awesome manifestations of the fiery power contained deep within the Earth. These formations are  essentially vents on the Earth's surface where molten rock, debris, and gases from the planet's interior are emitted. When thick magma and large amounts of gas build up under the surface, eruptions can be explosive, expelling lava,  rocks and ash into the air. Less gas and more viscous magma usually mean a less dramatic eruption, often causing  streams of lava to ooze from the vent.The mountain-like mounds that we associate with volcanoes are what remain after the material spewed during eruptions  has collected and hardened around the vent. This can happen over a period of weeks or many millions of years.Volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gasesto escape from a magma chamber below the surface.Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle.^[1] Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates coming together. Volcanoes can also form where there is stretching and thinning of the crust's interior plates, e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism.^[2] Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth. Volcanoes are usually not created where two tectonic plates slide past one another.Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. One such hazard is that volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the highoperating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine. Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere (or troposphere); however, they also absorb heat radiated up from the Earth, thereby warming the upper atmosphere (or stratosphere). Historically, so-called volcanic winters have caused catastrophic famines..

                                            PARTS OF VOLCANO

Magma - Molten rock beneath Earth's surface.

Parasitic Cone - A small cone-shaped volcano formed by an accumulation of volcanic debris.

Sill - A flat piece of rock formed when magma hardens in a crack in a volcano.

Vent - An opening in Earth's surface through which volcanic materials escape.

Flank - The side of a volcano.

Lava - Molten rock that erupts from a volcano that solidifies as it cools.

Crater - Mouth of a volcano - surrounds a volcanic vent.

Conduit - An underground passage magma travels through.

Summit - Highest point; apex

Throat - Entrance of a volcano. The part of the conduit that ejects lava and volcanic ash.

Ash - Fragments of lava or rock smaller than 2 mm in size that are blasted into the air by volcanic explosions.

Ash Cloud - A cloud of ash formed by volcanic explosions.

ACTIVE VOLCANOES - are those that have erupted over the last 10,000 years and                                                      and still continue to erupt. The Philippines has 21 active                                                           volcanoes, including the famous Mt. Mayon, which is                                                                probably the most active.

INACTIVE VOLCANOES - are those do not erupt as of today but have a potential                                                              to do so. Mt. Pinatubo in Pampanga, for example, was                                                              considered an inactive volcano until 1991, when it                                                                     erupted. It's eruption is now recorded as the second                                                                 largest eruption in the 20th century. Mt. Makiling,                                                                     Mt. Mariveles, and Mt. Apo are examples of inactive                                                                 volcano.

                  

                            TYPES OF VOLCANOES

                             COMPOSITE VOLCANO

Composite volcanoes are built by multiple eruptions, sometimes recurring over hundreds of thousands of years, sometimes over a few hundred. Andesite magma, the most common but not the only magma type, tends to form composite cones. Although andesitic composite cones are built mostly of fragmental debris, some of the magma intrudes fractures within the cones to form dike or sills. In this way, multiple intrusive events build a structural framework of dikes and sills that knits together the voluminous accumulation of volcanic rubble. Such a structure can stand higher than cones composed only of fragmental material. Composite cones can grow to such heights that their slopes become unstable and susceptible to collapse from the pull of gravity.Famous examples of composite cones are Mayon Volcano, Philippines, Mount Fuji in Japan, and Mount Rainier, Washington, U.S.A. Some composite volcanoes attain two to three thousand meters in height above their bases. Most composite volcanoes occur in chains and are separated by several tens of kilometers. There are numerous composite volcano chains on earth, notably around the Pacific rim, known as the "Rim of Fire".

                                 SHIELD VOLCANO

Shield volcanoes are the largest volcanoes in terms of volume, and in diameter can be tens to hundreds of kilometers across, or more. A shield volcano gets its name from its appearance. It is large in terms of area, but much flatter than the other two types of volcanoes. Viewed from above, it looks like a warrior's shield: slightly raised in the center, with long, gently-sloping sides.

                          CINDER CONE VOLCANO

Cinder cones are simple volcanoes which have a bowl-shaped crater at the summit and only grow to about a thousand feet, the size of a hill. They usually are created of eruptions from a single opening, unlike a strato-volcano or shield volcano which can erupt from many different openings.They are usually made of piles of lava, not ash. During the eruption, blobs ("cinders") of lava, blown into the air, break into small fragments that fall around the opening to the volcano. 

                     

                         VOLCANIC ERUPTION

An eruption occurs when magma, along with several materials, is ejected into the volcano's vent. Genrally, some of the effects observed during an eruption include earthquakes, release of ash clouds that results in the darkening of the sky, lahar (mudflows created when lava mixes wirth water) and flash floods, acid rain, and tsunamis, especially if the volcano is located near the coastline. 

REFLECTIONS:

A. Which concept on the topic did you find easy to understand? What made them interesting? 

- I easily understand because of its explanations and definitions.Its interesting because of its shape .

B. What were your personal discoveries or learnings while studying the topic?

-The types of volcanoes

C. Which area or concept do you like to expound more?

- The other types of volcanoes and the volcanic eruption.