地理一trench,mid-oceanic ridge的問題

請問trench,mid-oceanic ridge同 地震帶, plate movement 有無關??
當然有啦, 呢D features 都係由plate movement直接形成既.

trench,mid-oceanic
ridge 果到係唔係 地震同火山發出o既地方??
Trench- plates 相撞既地方=subduction zone, 由於有好大既壓力, 摩擦, 所以有斷層, 有火山, 有強烈地震.

mid-oceanic ridge - plates 移離對方, 所以沒有大壓力, 沒有斷層, 反而係裂口, 溶岩冷卻形成新地層. 所以過程比subduction zone 為慢, 斯文安靜地進行. 有火山, 例如冰島, 但地震不算多.

咁trench,mid-oceanic ridge 果到 又到
direction of plate movements 有無關??
當然有關.
Trench : plates 相撞既地方; mid-oceanic ridge : plates移離對方.

如果trench,mid-oceanic ridge同
地震帶, plate movement 無關的話， trench,mid-oceanic ridge E 兩個發出o既地方會唔會導致D咩??
唔明你想講導致D咩? 可否具體d?

仲
有，我想問點樣睇direction of plate movement??
我only 知道 當oceanic plate 遇到
continental plate 時，就係move against
咁其他 move apart and lateral
movement 係幾時發生??
首先, plate movement 唔係取決於佢係 continental 定係 oceanic.

Plate movement 可以想像成一煲粥上面浮著一堆薄脆.
粥 = 地慢mantle; 薄脆 = 板塊plates.
不論係continental 定係 oceanic, plates 都係浮係 mantle 之上. 即係大大小小不同的薄脆, 有d輕身d就係continental plates, 有d重身d就係oceanic plates.

當你將粥煲滾, 粥發生對流 [地慢mantle係有對流架], 將靜止既薄脆推動. 薄脆比粥輕, 不會沉, 但會橫向漂移 [板塊plates因地慢對流而橫向漂移]. 薄脆之間會有不同的漂移方向和速度, 在粥面上, 有d移離對方, 有d撞埋一齊.


圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/2/27/Oceanic_spreading.svg/220px-Oceanic_spreading.svg.png

所以, 唔係但凡oceanic plate 就要撞 continental plate, 而係, 佢地剛啱比mantle推向咩方向, 而發生 碰撞convergent, 移離divergent, 或擦身而過slide past.

而重點, continental plate 比 oceanic plate 為輕. 薄脆相撞, 重d個塊咪比輕d個塊責住囉, continental plate 和 oceanic plate 相撞, oceanic plate咪攝係continental plate下面, ==> subduction 囉. 例如 Philippines plate 撞 Eurasia plate 出現 Philippines Trench.

continental 撞 continental, 就會起出高山, 例如Indian plate 撞 Eurasia plate 出現 Himalayas.

兩continental plates移離, 就會有ridge, 甚至製造出ocean. 例如 North American plate 移離 Eurasian plate, South American plate 移離 African plate, [注意4塊都係continental] 製造出一個Atlantic Ocean!!

圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Plates_tect2_en.svg/300px-Plates_tect2_en.svg.png

Plate tectonics 比較抽象, 又無咩實驗做到 [除左㷛粥] ^_^
睇多d資料, 發揮下你既想像力, 先容易明白架!
http://en.wikipedia.org/wiki/Plate_tectonics

the formation of trench and mid-oceanic ridge is due to plate movements
ocean trench:
-destructive plate boundary(2 plates converge due to compressional force)
-formed along the subduction zone
mid-oceanic ridge:
-constructive plate boundary(2 plates diverge due to tensional force)
-mid-oceanic ridge formed by continuous swelling of magma

trench and mid-oceanic ridge are usually places that occur earthquakes and volcanic eruptions
converging plate boundaries:Cirum-Pacific region(Ring of Fire)
diverging plate boundaries:mid-oceanic region

formation of earthquakes:
-2 plates collide/diverge/slide past
-rock fractures
-stress built up
-sudden release of pressure
-produce vibration in the crust

formation of volcanic eruptions:
-2 plates collide/diverge
-stress built up
-melting of subduction zone intensifies stress(constructive plate boundary)
-folding and faulting lead to earthquakes
-increase lines of weakness
-magma rises through the cracks

direction of plate movement:
-when the magma in the mantle is diverging, tensional force is produced, so 2 oceanic plates diverge
-when the magma in the mantle is converging, compressional force is produced, 1 oceanic plate and 1 continental plate diverge / 2 continental plates diverge/ 2 oceanic plates diverge
-there is only one place in the world that the plates slide past each other (San Andreas Fault in California:Pacific Plate is moving north-westwards past the North America Plate)