Term | Definition |
crust | the outer layer of the earth,it consists of oceanic and continental crust. |
core | is in the inner layer of the earth, consists of iron and nickel |
mantle | makes up over 75% of earths volume, consists of several layers of rock . |
lithosphere | is the name given to the crust and upper part of the mantle. |
asthenosphere | is the region just below the lithosphere. |
plates | are the large ridged sections that the lithosphere is divided up into. |
convection currents | are in the mantle and are the main cause of plate movements |
subduction | when one plate sinks below the other |
fault line | is the line along which the plates slide |
extinct volcano | are volcanos that haven't erupted in historical times |
active volcano | are volcanos that are currently erupting or showing signs of unrest |
dormant volcanos | are volcanos that haven't erupted in at least 600 years and are now quiet but have high probabilities that they'll erupt again |
vent | the passage that goes up through a volcano cone to allow lava to erupt onto the surface |
crater | is a steep sided depression found at the top of a volcano |
basic lava | is the lava that is high in silica, causes it to be runny |
acidic lava | is the lava low in silica, causes it not to be runny |
lahar | is when ash and dust gets mixed with rain water or melted snow during a volcanic eruption |
intrusive | features inside the earths curst |
extrusive | features on the earths surface |
fissure | is a long crack on the earths surface |