Vulcanicity and Plate Movement
火山作用與板塊移動
The term ‘volcanology’ covers all the processes that molten rock material or magma rises into the crust, or is poured out on its surface, there to solidify as a crystalline or a semi- crystalline rock. And extrusive can be know as volcanic, that the volcanic vlucanicity, when associating with plate movement with reference to destructive plate margins, that the convergent plate margins.
火山作用是熔岩從上地幔流出地面。在地面冷卻形成不同的地形，如火山等。
Actually, most of the earth’s active and dormant volcanoes are associated with constructive, destructive, and some are related to transform plate margins. Although material in the mantle has a high temperature, it is kept in a semi-solid state because of the great pressure exerted upon it. However, if this pressure is released locally by folding, faulting or other movements at plate margins. Some of the semi-solid material becomes molten and rises, forcing its way into weaknesses in the crust, or onto the surface, where it cools, crystallizes and solidifies.
火山帶主要分佈在擴張性、擠壓性及穩定性板塊邊界。因為熔岩受壓，從地殼的裂縫向地面流出。
在環太平洋帶上，兩板塊碰撞。火山、離岸火山島孤在板塊邊界上形成。
Circum-Pacific is the ring around the Pacific Ocean basin. In South America, it includes Mountain Andes. In the Western Part of Pacific Ocean, the volcanic islands lie well offshore the North of Pacific Ocean to the Equator and form a chain of island called island arc. The islands include Alentians, Kurils, Japan, the Philippines, and other smaller islands. This island arc is the result of active volcanic activity. It is also called the ‘Ring of Fire’.
The mountain chain is formed at the Eurasian-Indonesian belt, it starts from the west of Alps and is across the Southern part of Europe and extends to the Himalayas. It is the inactive volcanic belt.
The crust is destroyed and mountain is built by the tectonic activities. The tectonic activities are active at the convergent zones that are produced by the compressing force. The radioactive energy is released in the earth’s core. The hot magma rises from the core to the upper mantle. The plates are pushed towards. The denser and thinner oceanic crust is drawn beneath under the continental crust. The edge of the oceanic crust is melted and the pressures increase. The magma flows out along the cracks while the plates collide. The volcanic island is formed along the divergent plate margins. At this subduction zone, the crust is destroyed and the volcanoes are formed. It implies that the plates are unstable.
因為地殼碰撞，大洋板塊向地幔俯衝，形成俯衝帶。因為岩漿受壓沿地殼的裂縫噴出，形成火山或火山島。
在建設性板塊邊界上，兩板塊分離移動。在大西洋中脊上，海底火山、火山島及熔岩流形成。
Due to the tension force, the plates become unstable. The eruption of volcanoes is the major processes and geologic phenomena that are found at the divergent plate margins. When the plates move apart. It is because the heat is released from the earth’s core. While the crust is cracked, the magma flows out from the fissure on the earth’ surface as lava. When the lava is cooled and solidified. After the several eruptions, the volcanoes are formed. At the Mid-Atlantic Ridge, the plates move apart. The magma rises from the mantle and flows out to the ocean floor. The chain of volcanic islands are found along the plate margins. As the plates move, the crust is fracturing. The transform faults are also found.
地殼受張力作用下，兩板塊分離移動。因為岩裝受壓，沿地殼的裂縫流出。因為熔岩受冷及凝固，形成火山島。在大西洋中脊上，地殼受壓破裂，有斷層出現。
Conclusion
Therefore, volcanoes are formed because the plates move apart or towards. It implies that the plates are not stable. The lands are destroyed or the new crusts are formed. The fracturing and folding are actively occurred.
火山及火山島在擴張性、擠壓性等板塊邊界上形成。這些板塊構造地形顯示出板塊在不穩定的情況下，板塊出現了移動，各種地形形成。
By Amethyst Cheung