Under our Feet
What is the level between the crust and the mantle?
Between the Richter and the MM scale, which one is most reliable for measuring the energy released from an earthquake?
Richter scale
Which type of mountains is formed by tectonic plates being pushed together?
Folded mountain
Where do most earthquakes happen?
circum-Pacific belt (Ring of Fire)
What is the channel through which hot gases, rock, and ash are ejected.
Vent
What is the most abundant element in the crust?
Hypocenter
Which lava hardens to form either a smooth or a ropey surface?
Pahoehoe
What are the smaller earthquakes that often follow the larger earthquakes?
Aftershocks
What are particles or blocks of solid volcanic ejecta?
What makes up the lithosphere?
The crust and upper mantle
What are volcanic bombs?
Volcanic ejecta formed when lava is thrown as a liquid and then turns into a solid before it hits the ground
What is a caldera?
A huge bowl-shaped crater formed from an empty magma chamber collapses in on itself.
Daily Double:
Where do most earthquakes originate from?
Fairly close to the earth's surface (shallow focus)
What type of volcano is violently formed from erupted volcanic ash and rock fragments (cinders)
Cinder-cone volcanoes
Where is the Gutenberg Discontuity?
Between the mantle and the core
Which two kinds of seismic waves cause the most damage to buildings and why?
P and surface waves because they move up and down.
laccolith - the magma bulges the overlying rock upward
Batholith - much larger than a laccolith, form the base of the Sierra Mountain range
Absorb some of the seismic energy from seismic waves. Leads to the buildings not being deformed.
What is the difference between a dike and a sill?
Dike - a vertical, sheetlike mass of igneous rocks
Sill - a horizontal, sheetlike mass of igneous rock
What is a fault line?
The fracture zone between stationary and moving rocks.
In order, what are the three kinds of seismic waves, and what substances can they travel through?
P-waves: travel through solid, liquid, or gas
S-waves: only travel through solids
Surface waves: only travel through solids.
What is the elastic rebound theory?
Tectonic forces cause the rocks to slowly bend at a fault line. During an earthquake, rocks rip violently to an unbent position.
What's the difference between Modified Mercalli scale and Richter Magnitude scale?
Modified Mercalli - Based off of what people feel and structural damage
Richter scale - mathematical rating system based off of an earthquake's seismograph
What's the difference between volcanic ash and lapilli?
Volcanic ash - pyroclastic particles less than 2 mm in diameter
Lapilli - ejecta between 2 and 64 mm in diameter