Radiometric dating from hawaiian volcanoes

Volcanic Eruptions In general, magmas that are generated deep within the Earth begin to rise because they are less dense than the surrounding solid rocks.As they rise they may encounter a depth or pressure where the dissolved gas no longer can be held in solution in the magma, and the gas begins to form a separate phase (i.e.it makes bubbles just like in a bottle of carbonated beverage when the pressure is reduced).When a gas bubble forms, it will also continue to grow in size as pressure is reduced and more of the gas comes out of solution. If the liquid part of the magma has a low viscosity, then the gas can expand relatively easily.

Viscosity is an important property in determining the eruptive behavior of magmas.This will cause an explosive volcanic eruption and the production of pyroclastic material.Explosive Eruptions Explosive eruptions are favored by high gas content & high viscosity magmas (andesitic to rhyolitic magmas).gas emission from Lake Nyos in Cameroon killed more than 1700 people and 3000 cattle.The gases can also have an effect on the atmosphere and climate.

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