Thick layers of sediment may accumulate in the trench, and these and the subducting plate rocks contain water that subduction transports to depth, which at higher temperatures and pressures enables melting to occur and ‘magmas’ to form. The hot buoyant magma rises up to the surface, forming chains of volcanoes.Read More →
Non-explosive Eruptions Because the composition of magma is different in different volcanoes, the properties of the lava are different. In effusive eruptions, lava flows are relatively calm and do not explode out of the volcano. Does basic lava erupt explosively? Basaltic magma, which is high in temperature, very low onRead More →
Scoria is common in areas of recent volcanism, such as the Canary Islands and the Italian volcanoes. It is relatively low density due to its vesicles, bu it is not as light as pumice. Also differs from pumice in that it has larger vesicles with thicker walls. Is scoria plutonicRead More →
Since there are on average between 50 and 60 volcanoes that erupt each year somewhere on Earth (about 1 every week), some of Earth’s volcanoes may actually erupt within a few days or hours of each other. Where are the majority of volcanoes formed? The Ring of Fire, also referredRead More →
Volcanoes happen when magma rises to the surface of the earth, which causes bubbles of gas to appear in it. … This gas can cause pressure to build up in the mountain, and it eventually explodes. When the magma bursts out of the earth, it is called lava. What areRead More →
Activity within a plate is called intraplate activity. Most intraplate activity occurs at hotspots. Hotspot volcanoes erupt mostly on oceanic crust. What is an intraplate location? Intraplate pertains to processes within the plates. Those near the ocean boundary are at the boundary between two plates (interplate). … What causes intraplateRead More →
Volcanoes usually have a life of many thousands of years. Once a volcano has begun to erupt, it usually takes about ten years before that particular eruption comes to an end. What volcano probably will never erupt again? A dormant volcano is an active volcano that is not erupting, butRead More →
A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, earthquakes are common and magma (molten rock) rises from the Earth’s mantle to the surface, solidifying to create new oceanic crust. How convergent plates cause earthquakes? Convergent plate boundaries The plates move towards oneRead More →
Submarine volcanoes that do not reach sea level are called seamounts. Can there be lava in water? Sometimes, however, streams of lava pour into the sea with little or no steam, as if the lava were not hot at all. … Obviously, there’s a lot more water than incandescent lava,Read More →
As the plate sinks it heats up and dehydrates, water is released from minerals and cracks in the sinking plate. This water is hotter than the surrounding rocks and rises up into the mantle. The addition of these hot fluids lowers the pressure and causes the mantle rocks to melt.Read More →