One of the key reasons for Federation was to achieve a united defence force which could better protect Australia. Around the 1880s, the Australian colonies had become increasingly concerned over the close proximity of foreign powers.
Split and merge into it. Answered by The Community. Making the world better, one answer at a time. Dissolved gases trapped in the magma provides the force that causes magma to erupt to the surface. Magma is molten material before it reaches the surface and is lava.
As magma moves beneath a volcano prior to an eruption, it often generates earthquakes, causes the surface of the volcano to swell, and causes the amount of gases emitted by the volcano to increase.s magma moves beneath a volcano prior to an eruption, it often generates earthquakes, causes the surface of the volcano to swell, and causes the amount of gases emitted by the volcano to increase.