Random facts
The majority of volcanoes occur along?
Plate boundaries
If a volcano oozes out lava then it is most likely a?
As magma rises to the surface, the?
pressure on it decreases
What does high silica content mean for the magma and the explosion of a volcano?
High silica=high viscosity=gasses trapped=explosion
List all types of volcanoes:
Cinder Cone (scoria), Shield, Composite (strato), Caldera, and Lava Dome
A volcano occurs along a convergent plate boundary. Which type of volcano is it most likely?
stratovolcano
If a volcano has violent eruptions, then it is most likely a?
cinder cone
The largest of the igneous intrusions are called?
batholiths
What is the most violent type of volcano and why?
Composite or Stratovolcanoes are the most dangerous volcanoes to humans and animals because they are very explosive, producing toxic gas and flying volcanic fragments. Explosive volcanic eruptions, which are common to stratovolcanoes, pose serious threats to aviation travel.
Describe a pyroclastic flow
a high-density mixture of hot ash and rock fragments with hot gasses formed by a volcanic explosion or aerial expulsion from a volcanic vent.
When a volcano erupts and empties its magma chamber, and the weight above causes it to?
collapse and form a caldera
A volcano with an explosive eruption most likely has what kind of magma inside it?
Thick, viscous lava
The principal dissolved gases in lava are?
water and carbon dioxide
What type of gasses make a volcano deadly?
Carbon Dioxide can suffocate you and sulfur dioxide can cause acid rain
Describe a lahar
a wet, cement-like mixture of water, mud, and volcanic rock fragments that flows down the slopes of a volcano and its river valleys.
When magma rises up in the middle of a plate it forms a
hot spot
Which element makes lava more viscous?
silicon
Oceanic plates are less dense than continental plates. true of false
false
List characteristics of contour lines.
-Never cross, the closer together the steeper, closed depressions are marked with tick, every 5th is darker marking the interval
what are characteristics of Basalt:
Basaltic lavas are more fluid than andesites or dacites, which contain more silica.
Most of the volcanoes are located around the?
pacific ring
Which type of pyroclastic material is the largest?
bombs
The type of minerals dissolved in the magma/lava can affect the viscosity of the molten rock.
true or false
Describe the difference between a high silica and low silica magma
Magma rich with silica tends to have more dissolved gasses. Silica content affects how the silica flows. Magma rich in silica flow slower. Silica rich magmas tend to be explosive. Low silica magma flows freely.
What increase the speed of magma:
It increases with the temperature.