Where are Volcanoes located? Volcanoes are most commonly found along plate boundaries. The earth's crust is cracked and the pieces of the Earth's crust formed by the cracks are called tectonic plates.
The plates are continually moving (albeit very slowly, a few millimeters a year) and this movement helps to form volcanoes.
Vocabulary: Magma岩浆yán jiāng : the molten rock at earth's core.
Lava熔岩róng yán: the melted rock that comes out of a volcano.
Crater火山口huǒ shān kǒu: a circular-shaped depression at the top of a volcano formed by collapse from a large eruption.
Vent (Main vent and side vent) 喷口pēn kǒu: The hole where magma comes out of the volcano.
Magma chamber: Magma stored in a large area under a volcano.
Cone 锥形zhuī xíng: The shape of a volcano
Island: A piese of land surrounded by water. They can be of volcanic origin, as they are created by underwater volcanoes from which magma comes to the surface and solidifies.
Volcanic eruptions can create different types of volcanic mountains
1. Cinder cone 火山渣锥
Have a bowl shaped crater, steep sides, but is smaller that composite volcanoes.
Made of mostly loose, grainy cinders and very little lava.
Eruptions are often sudden and fast.
2. Shield volcano 盾形火山
Board with gentle slopes, large, with a large crater at the summit, characteristic of the eruption of fluid, basaltic lava.
Eruptions are generally slow.
3. Composite volcano(Stratovolcano) 复合火山
Large, symetrical, with steep sides.
Built with alternating layers of lava flow, ash, and cinder.
Characterized by a steep profile and periodic explosive and dangerous eruptions.
Three stages of Volcanoes-ACTIVE, DORMANT, AND EXTINCT 1. An active volcano is either erupting or showing signs that it is going to erupt, such as emitting gas. 2. A dormant volcano is not active, but it could become active again. 3. An extinct volcano is unlikely to erupt again.
The Ring of Fire The area encircling the Pacific Ocean is called the "Ring of Fire," because its edges mark a circle of high volcanic and seismic activity (earthquakes). Most of the active volcanoes on Earth are located on this circumference.