Earthquakes Part I
__________ is a force that acts on rocks to change their shape or volume.
Stress
__________ is the shaking and trembling that results from the movement of rock beneath Earth’s surface.
Earthquake
___________ - a weak spot in the crust where molten material or magma comes to the surface
Volcano
_______ is formed when magma reaches the surface
Lava
_____________ - a volcano that is “dead” or unlikely to erupt again
Extinct
_________ pulls on the crust, stretching rock so that it becomes thinner in the middle
Tension
______________ - the area beneath Earth’s surface where rock that is under stress breaks, triggering an earthquake
Focus
_____________ - a molten mixture of rock-forming substances, gases, and water from the mantle
Magma
_____________ - an area where material from deep within the mantle rises and then melts, creating volcanoes in the middle of tectonic plates or near plates boundaries
Hot Spot
________ Volcanoes - formed by thin layers of lava which gradually build a wide, gently sloping mountain
Shield
____________ - a stress force that squeezes rock until it folds or breaks
Compression
___________ - the point on the surface directly above the focus
Epicenter
how fast lava flows depends on its physical and __________ properties
chemical
___________ is a substance that cannot be broken down into other substances (oxygen, hydrogen, carbon, sodium etc.)
Element
____________ volcano - lava that has high viscosity, materials build up around the vent in a steep, cone-shaped hill or small mountain
Cinder cone
___________ - a stress force that pushes a mass of rock in two opposite directions
Shearing
_______________ - seismic waves that compress and expand the ground like an accordian
P waves
______________ - a substance made of two or more elements that have been chemically combined (water, carbon dioxide, salt)
Compound
Each substance on earth has physical and chemical properties that ___________ how it might behave
predict
____________ volcanoes-tall, cone shaped mountains in which layers of lava alternate with layers of ash
composite
When stress builds up in the rock, the rock breaks, creating a _________.
Fault
_________ - seismic waves that vibrate from side to side as well as up and down, cannot move through liquids
S Waves
_________________ - the tendency of a fluid to resist flowing
Viscosity
_____________ Property- any characteristics of a substance that can be observed or measured without changing the composition of the substance
Physical
composite volcanoes are also known as _______________.
Stratovolcanoes
_________ Faults- the fault is at an angle so one block of rock lies above the fault while the other block lies below the fault. Hanging wall slips lower than the foot wall.
Normal
_____________ - move more slowly than P and S waves but produce ground movements
Surface waves
_____________ Property- any property that produces a change in the composition of matter
Chemical
Because liquids differ in ____________, some liquids flow more easily than others
Viscocity
Some eruptions of lava form high, level areas called lava ______________.
Plateaus
_________ Fault - occurs in places where the rock of the crust is pushed together. Hanging wall rises above the foot wall.
Reverse
___________ - measures the tilting or rising of the ground
Tiltmeters
The viscosity of magma depends upon its __________ content and temperature
silica
__________ - a compound made up of oxygen and silicon
Silica
____________ - a huge hole left by the collapse of a volcanic mountain when it empties its magma chamber
Caldera
____________ faults - places where plates move past each other sideways, with very little up or down motion
Strike-Slip
____________ - measures horizontal movement between two plates
Creep Meters
_____________________ - the pocket of magma
beneath the surface where magma
collects
Magma chamber
____________ - a long tube on the ground that connects the magma chamber to Earth’s surface
Pipe
Volcanic _________ is very fertile and can support excellent plant growth
soil
___________ - when an earthquake’s violent shaking suddenly turns loose, soft soil into liquid mud
Liquefaction
______________ - an earthquake in the same area that could happen hours, days, or months later
Aftershocks
______________ - an opening through which molten rock and gas leave the volcano
Vent
____________ - a bowl-shaped area that may form at the top of a volcano around the central vent
Crater
__________ Eruption - Magma has low viscosity and flows easily, Lava Oozes quietly from the vent and can flow for many kilometers
Quiet
___________ - water displaced by a large earthquake
Tsunami
___________ waves are used to locate where exactly the epicenter of an earthquake was
Seismic
____________ - stage of a volcano that has erupted recently and a possibility it may erupt again soon
Active
____________ - stage of a volcano that could possibly become active
Dormant
A volcanic ____________ is a mass of molten rock larger than 64 mm in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. These can be as big as a car.
bomb