1. RAIN IN THE FINE ASH of Pompeii turned it into something like plaster, beauti
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Question
1. RAIN IN THE FINE ASH of Pompeii turned it into something like plaster, beautifully preserving the shapes of bodies. Herculaneum, ten miles away and on Vesuvius’s windward flank, was buried by glowing avalanches of tephra and hot gases (known in geology as nuées ardentes). Notably absent was flowing lava. If there was any in the 79 eruption, it stopped high on the mountain. After seventeen or eighteen centuries, archeologists might arrive to scrape away indurated ash or mud, but digs do not happen in basalt. The eruption on Heimaey began in fields close to a farm called Kirkjubaer, in a setting so beautiful that to think of it is painful for people who returned to the island. The hay meadows and pastureland were a little more than a hundred feet above the sea, to which they sloped gently, everywhere presenting a view of nearby islands, of the reassuring mainland, and, on bright days, of the not so affirmative Hekla. The farmer of Kirkjubaer sold milk in town. On the night of the eruption, he shot his cows, left the farm, and went to the mainland. He never came back.
2. Thorbjorn went to Heimaey specifically to measure lava temperatures, but mainly to be on the scene. He saw the classic pattern the eruption was following. The lava curtain drew in from the two ends and began to concentrate in the place where the volcano would grow.
Through this two paragraph, explain volcanic eruption, crustal movement, the rock formation, plate movement, lava. And what is relations between the two paragraph and these word.
Explanation / Answer
Volcanic eruption: When a very large amount of lava (melted rocks), dust, gases and water vapours are thrown out of the volcano, this process is called volcanic eruption. Such type of volcano is called an Active volcano. The dust may remain suspended for a number of days in the atmosphere while the heavier particles settle down quickly as volcanic ash in the nearby areas.
Crustal movement and plate movement: Crust is the outermost layer of the earth. It is divided into a no of parts known as plates and floats on the layer of molten magma on top of aesthenosphere ( the topmost layer of the mantle). There are seven large plates and many small plates. Due to thermal convectional currents in the earth's internal heat hotter magma flows towards the top and cools down and again sinks. Due to this movement of magma, the crustal plates on the top also move. This movement is called crustal movement.
The rock formation: Rocks are solid aggregates of one or more minerals. There are three types of rocks
Igneous rocks: This type of rock is formed by the cooling of hot lava. They are formed either in the earth crust or on the earth surface when the magma flows out, cools and solidifies. Examples of igneous rocks are basalt, obsidian, pumice, rhyolite, scoria etc.
Sedimentary rocks: These are formed by deposition and subsequent solidification of sediments in some place like in a water body. These include sandstone, siltstone, shale etc. Coal is also a type of organic sedimentary rock.
Metamorphic rocks: They are formed by metamorphosis of upper two types of rocks, by the action of extreme heat and pressure which change the physical and chemical structure of these rocks. Examples include gneiss, slate, marble, schist, and quartzite.
One thing to note is that one type of rock can be converted into another type under favourable conditions, like metamorphic rocks may change to igneous if the melt under high temperature.
Lava: Magma is molten rocks inside the earth crust. When this magma comes out of crust then it is called lava.
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