LESSON-1 Flashcards
(21 cards)
What is a volcano?
An opening in the earth’s crust through which magma, ash, and gas erupts.
Volcanoes often form a hill or mountain as layers of rock and ashes build up from eruptions.
What is magma that reaches the surface through a volcanic vent called?
Lava
What type of volcano is Mount Pinatubo?
Active stratovolcano
What is the smallest active volcano in the world?
Taal Volcano
What are shield volcanoes primarily constructed from?
Basaltic and/or andesitic lava flows which were very fluid when erupted.
What percentage of all earthquakes occur around the Pacific Ocean basin?
About 80%
Where do volcanoes mostly form?
At divergent boundaries (mid-ocean ridges) or convergent boundaries (subduction ridges).
What is the movement of a convergent plate boundary?
Two tectonic plates move toward each other.
What defines an active volcano?
A volcano known to have erupted in recent times.
Give an example of an active volcano.
- Mount Mayon
- Taal Volcano
- Mount Kanlaon
What is a dormant volcano?
A volcano that has erupted in the last 2000 years but not recently.
Give an example of a dormant volcano.
Mount Pinatubo
What is an extinct volcano?
A volcano that is not expected to erupt again.
What are the phases of a volcanic eruption?
- Preparation Phase
- Eruption Phase
- Ending Phase
What happens during the preparation phase of a volcanic eruption?
The magma chamber is being filled with magma and steam or smoke can be observed.
What occurs during the eruption phase?
Pressure builds up inside the magma chamber, leading to an eruption as magma is pushed to the opening.
What happens during the ending phase of a volcanic eruption?
The magma chamber is empty, which may weaken the walls of the conduit and cause a collapse into a crater or caldera.
What is a shield volcano?
A type of volcano constructed almost entirely of fluid lava flows.
Fill in the blank: An _______ volcano is inactive but not extinct.
Dormant
Fill in the blank: The _______ is where tectonic plates move away from each other.
Constructive plate boundary
Fill in the blank: A volcano that is not expected to erupt again is called _______.
Extinct
