VOLCANOES

A volcanoes is a sudden and abrupt explosion in the crust of the earth through which magma, gas, smoke and solid material is ejected. The hot molten magma below the earth’s surface is brought to the surface as lava. Lava is a very high temperature, varying from 800 to 1300 Celsius and contains steam and several other gases. All these materials are ejection at greater pressure through a pipe which as it’s ‘Vent’ or ‘Neck’.

The lava forms a cone-like feature on the surface of the earth which is known as ‘Volcanic Cone’. The top of the cone has funnel-shaped or saucer-shaped depression which is known as the crater. The diameter of the crater may from a few meter to a few kilometers. Sometimes lava comes to the surface through joints on the sides of main cone and forms secondary cones.

The three types of materials including gases, liquids, and solids are ejection at the time of a volcanic eruption.

Gases. The gaseous substances are mainly composed of stream, products being hydrochloric acid, ammonium chloride, sulphur dioxide, hydrogen sulphide, hydrogen and carbon dioxide. Water vapour is the most important of all the gases VOLCANOES

A volcanoes is a sudden and abrupt explosion in the crust of the earth through which magma, gas, smoke and solid material is ejected. The hot molten magma below the earth’s surface is brought to the surface as lava. Lava is a very high temperature, varying from 800 to 1300 Celsius and contains steam and several other gases. All these materials are ejection at greater pressure through a pipe which as it’s ‘Vent’ or ‘Neck’.

The lava forms a cone-like feature on the surface of the earth which is known as ‘Volcanic Cone’. The top of the cone has funnel-shaped or saucer-shaped depression which is known as the crater. The diameter of the crater may from a few meter to a few kilometers. Sometimes lava comes to the surface through joints on the sides of main cone and forms

as it accounts for 60% to 90% of all the gases thrown out by a volcano. This water vapour causes heavy rainfall after condensation in the atmosphere.

Liquids. The liquid matter is the lava. The temperature of freshly ejected lava may range between (600 to 1200) Celsius. Water also comes out along with lava. The speed of lava flow depends upon its composition, mobility and the slope of the ground. Usually the movements is very slow and even a speed of 15 km per hour is rarely achieved. But sometimes the speed may be as high as 80 km per hour.

Solids. The lava in the vertical passage gets solidified. The next volcanic eruption through the pipe is accompanied by explosion of highly compressed gases throwing out block of solidified lava from inside the choked pipe. The solid material consists of fine ash and dust particles and angular fragments mostly of lava rock blow up from within the vent. If the diameter of the solid block thrown out by a volcano is more than 33 mm. it is known as volcanic bomb or blocks. At places volcanic bombs weighing 60 tons have seen but their number is small.