Science L4 4th Qrt Flashcards
What is an opening on the the Earth’s crust through which hot molten rock flows out from deep inside the Earth?
Volcano
What is a hot magma rock inside the Earth?
Magma
Magma that reaches the surface of the Earth. What is this?
Lava
What is the process that includes the movement of magma toward the surface of the Earth?
Volcanism
How many are the potentially active volcanoes around the world?
1,500
What occurs in belts that extend across continents and oceans?
Volcanoes
What is a major volcanic belt?
Ring of Fire
This comprises the many volcanoes that rime the Pacific Ocean. What is this?
Ring of Fire
What is the process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle?
Subduction
What forms along the mid-ocean ridges, which mark spreading boundaries?
Volcanoes
What are long, underwater mountain ranges that sometimes have rift valleys down their centers?
Ridges
What is a deep valley along spreading boundary?
Rift valley
Where may two oceanic plates collide?
Volcanoes
What is a string of volcanic islands called?
Island arc
This are the certain points within the mantle. What is this?
Hot spots
When magma from the hot spot reaches the surface, a ___-____ _______ is formed.
Hot-spot volcano
What is a volcano that had its last eruption more than 10 000 years ago and is not expected to erupt again in the foreseeable future?
Extinct volcano
What may supply magma to two or more volcanoes simultaneously?
Hot spot
What has many active volcanoes?
The Philippines
It is a major zone of active volcanoes formed by subducting plates encircling the Pacific Ocean. What is this?
The Pacific Ring of Fire
When magma from the mantle seeps through the crust, it forms within the crust a cavity called a _____ _______.
Magma chamber
What is the main duct or hole through which magma exits the volcano?
Central vent
What is a mountain or hill that forms the visible part of the volcano above the surface?
Volcanic cone
What is the top of the central vent through which most of the magma exit?
Crater
Magma seeps through the side of the volcanic cone forming ____ _____.
Side vents
What is an underground rock layer where water is collected?
Aquifer
What is a volcano that stops emitting heat, ash, and magma?
Inactive volcanoes
The empty magma chamber is a hollow cave and it usually cannot support to collapse into a hole called _______.
Caldera
When rain water fill up the caldera, it becomes a ______ ____.
Crater lake
What occur when then pressure exerted by the surrounding rocks on magma decreases as magma moves upward to the surface?
Volcanic activity
