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Which kinds of eruptions pose the greatest risk to humans?

Falling ashes pose the greatest threat to humans. The falling ashes from the explosive eruption can disrupt human activities to as far as hundreds of miles downhill. Tentatively, the ashes reduce visibility in air travel as well as damage jet engines during flights.

Which kind of eruptions poses comparatively low risk?

Phreatic eruption poses little danger as it does not exhibit magma it instead causes granulation of rocks

Why do pyroclastic flows travel faster and kill more people than do lava flows?

Pyroclastic flow are high speed avalanches that consist of rock fragments , hot ash as well as a gas that moves downwards during eruptions .As such the flow has a temperature that exceeds 1500 degrees and often move at speeds of 100-150 miles per hour. As opposed to viscous flow of lava flows that has a speed of 5-10 miles per hour, it would cause considerable damage on everything on its pathway.

What is the difference between a crater and a caldera?

The major difference between caldera and craters lies about the size and the formation process. As such, calderas collapses are associated with explosive volcanism. Tentatively, funnel shaped calderas are a result of flank collapse. On the other hand, craters are in most instances do not exceed more than a few hundred meters in diameter.

Why do explosive eruptions occasionally affect global climate?

The injection of sulfur dioxide into the atmosphere adversely affects the global change. As such, the aerosols result of reflection of the sun’s radiation, as a result cooling the Earth’s stratosphere. As such it reduces the earth’s temperature by up to half a degree for a period of one to three years.

Why is it not possible to assign a single melting temperature to a rock?

This is impossible as the rock composition adversely affects the melting point of the rocks. Tentatively, different minerals have different melting points as such it is impossible to assign a single melting point of a rock

 How does water affect the melting temperatures of a rock?

The existence of volatile phases in a rock under pressure may balance a melt fraction as such; the presence of water (0.8%) may effectively reduce the melting point by as much as 100 °C

When and how can a rock melt without increasing in temperature?

Rocks can melt at low temperatures in the presence of volatiles that include water and carbon dioxide. As the water saturates the lithosphere, water is forced out and it percolates into the rock adversely reducing its melting point. Undoubtedly, the sudden change in melting point causes the rock to melt.

How does fractional melting separate different minerals from one another?

Fractional melting takes place when minerals from the magma cool and crystallize out of the magma. As such, the crystals that melt the first will crystallize out first when the magma starts cooling. Tentatively, mafic mineral is seen to crystallize out first, followed by the felsic minerals.

What is the difference between fractional crystallization and fractional melting?

Fractional crystallization is a separation technique that depends on liquid-solid transition and it allows for multicomponent mixtures to separate into constricted fractions. Contrastingly, fractional melting takes place when the melt is constantly extracted from the residue during ascension process of the magma through the mantle.

How can magma form an igneous rock of one composition and a residual magma of another?

Magmas of various composition might mix with one another to form one com[poun , as the magma cools it may contain the same compound as such forming ignous rocks that has the same mineral composition.

What is the difference between a continues and a discontinuous reaction series?

Discontinuous series relies on one mineral plagioclase feldspar, while the sodium calcium exchange to Sodium occurs with respect to surrounding condition like temperature. On the other hand, continuous Bowen’s reaction is the reaction that of crystals with water occurs continuosly . Tentatively it relies on different mineral exchange with temperature as opposed to the discontinuous reaction.

What are some common kinds of plutons?



 How do plutons become visible at earth’s surface?

In the case where these plutons are formed on grounds that are susceptible to erosion , become visible after the surface has undergone intensive As such, after the ground has been exposed they thus become exposed.

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