Iceland volcanoes are very fluid so all gases come out. If the fluid is stiff the gases cant come out and they choke; pyroccastic broken by fire. Volcanoes in i taly, they thought volcanoes were caused by coal. The not so pacific ocean: its floor is being cloched by surrounding continents. Australia is moving north and will be in modern tokyo. Ring of fire; dense volcanoes and earthquakes and tsumanis; sea floor lowered or raised after earthquakes. The deepest earthquakes 700 kilometres down, they maintain their integrity. The oceanic crust is made of basalt, large amount of sea water and sediments and melted we produce silicic magma. Deep water trenches is where the ocean floor is just going down to the subduction zone. New zealand is a small island, it is the tip of a much larger land mass, zealandia and it is almost a continent underwater. The teeth like marks indicate the direction of subduction www. notesolution. com.