Abeka 8th grade Science Test 2

Circum-Pacific Belt

80% of all earthquakes occur here

shallow focus

85% of earthquakes are this type

Geographic Information System (GIS)

A computer system that stores and processes geographic data from various sources

anticline

A fold in rock that bends upward into an arch

The rocks were polished by rapid motion of the fault

A slickenside is a short cliff along a fault that has been polished smooth. How do slickensides prove evidence for the elastic rebound theory?

seismometer, to detect earthquakes caused by underground pressure

A volcanologist is placing a volcano to help predict when a volcano little rat. What instrument is he most likely to choose?

Modified Mercalli scale, because each location has its own value

After an earthquake, the U.S. Geological Survey often publishes a ShakeMap. The ShakeMap shows how the strength of an earthquake varies throughout the affected area. Which earthquake strength scale is used and why?

True

Among rock beneath the surface of the world is called magma

Molten rock pushes up overlaying rock layers without reaching the surface.

Describe how tall mountains form.

Fixed-base system- base of building is directly on the bed rock. Allows the buildings beams and joints to absorb the seismic energy. The downside to this construction is that the building can be deformed. Base-isolated system- The building rests on isolators that absorb the seismic energy. The isolators act as a movable "skills" that separate the building from the foundation. The building rests on isolators that absorb the seismic energy. The isolators act as movable "stilts" that separates the building from the foundation. Energy-dissipating device- Device is added to structures to absorb some of the seismic energy. This lesson is the stress on the building, minimizing the formation.

ESSEY: An engineer is designing a new steel skyscraper that will be built in an area that receives frequent earthquakes. He needs to choose one technique to use to reduce the damage the building will receive in an earthquake. Compare two different techniques that he could used to reduce earthquake damage. Recommend one of the techniques; give reasons why you chose that technique instead of the other one.

p waves

Faster type of earthquake waves are S waves

aa

Harden lava that form is rough, jagged rocks with a crumbly texture

Most volcanoes the peer to be located along a subduction zones

How does the existence of the ring of fire proof evidence for plate to tonics?

volcanic blocks

Large, irregular shaped lump made of lava that harden before being thrown out of a volcano

pillow lava

Lava and water solidifies almost instantly, forming rounded structures

Point IV is 60 feet higher

Point IV is 60 feet higherWhat is the approximate difference in elevation between point I and IV?

true

Small earthquakes that often thought of a large earthquake at circle intervals are called aftershocks

lapilli

Solid eject a larger than 2mm but less than 64 mm in diameter

geology

Study of the earth

pyroclastic flow

Superheated cloud of gas and small particles that travel as an avalanche

core

The central part of the earth below the mantle

igneous intrusion

The general name for a massive underground volcanic rock is a caldera

Solid

The inner core of the earth is thought to be what?

Volcanic Explosivity Index (VEI)

The strength of a volcano eruption is measured using a scale called the what?

seismology

The study of earthquakes

magma chamber

The underground lava tunnel is the actual source of a volcanic eruption.

A dike is vertical; a sill is horizontal

What is the main difference between a dike and a sill?

Point II

Which point has the steeper slope?

Modified Mercalli Scale

a 12 point scale developed to evaluate earthquake intensity based on the amount of damage to various structures

volcanic mountian

a type of mountain formed when molten rock erupts from a whole in the earth's crust

dormant volcano

an inactive volcano that could erupt again

volcano

an opening in the earth's surface through which hot gases, ash, and molten rock are ejected from the earth's interior

Moho

boundary between crust and mantle

A low-viscosity magma most likely...

causes a volcanic eruption to be violent

moment magnitude scale

considered the most reliable method for measuring an earthquake's magnitude

sediments

deposits of sand, mineral fragments, or organic materials usually left by wind or water

Earth's interior

earthquake waves can provide us with information about

Alpide belt

earthquake zone stretching from southern Europe to Indonesia

tectonic earthquakes

earthquakes that result from sudden movements of rock beneath the earth's surface

lava tunnels

form when the surface of a large lava flow hardens but the lava beneath remains molten and continues to flow

composite volcano

forms partly through explosive eruptions of cinders from the crater and partly through mild lava flows that pour out of cracks on the cone's flanks

pahoehoe

hardened lava with a surface that is either smooth or ropy

measuring travel time of seismic waves

how scientists determine the point where an earthquake begins

calderas

huge bowl shaped craters thought to form when the magma chamber beneath a volcano is emptied of magma causing it to collapse under its own weight

catastrophic plate tectonics

idea that rapid movement of tectonic plates during the Flood is responsible for most of Earth's features

volcanic bombs

large almond or teardrop shaped pieces of ejecta formed when lava solidifies after being thrown high into the air

true

mass of underground volcanic rock that is similar to a laccolith but much larger is a batholiths

oxygen

most abundant element in the earth's crust

pyroclast

particles or blocks of solid volcanic ejecta

Asthenosphere

plastic rock on which the tectonic plates float is called the lithosphere

hypocenter (or focus)

point below the surface where earthquake begins

epicenter

point on Earth's surface directly above an earthquake's focus

thrust fault

results when rocks on one side of a fault are shoved on top of the rocks on the other side

elastic rebound theory

rocks on either side of a fault spring back to a position of little or no strain at the moment of an earthquake, triggering vibrations in the earth's crust

volcanic ash

solid particles less than 2mm in diameter

transition zone

the area between the upper mantle and the lower mantle

core-mantle boundary

the bottom of the mantle

vent

the channel in a volcano through which gases, ash, and molten rock are ejected from the earth's interior

crust

the earth's outer layer made of solid rock

fault

the fracture zone between stationary and moving rocks

mantle

the middle of the earth's three main layers

folded mountains

these are thought to have formed when the edges of two adjacent tectonic plates were pushed together, causing the layers to buckle like a wrinkled rug

Seismograph

used to record the vibrations caused by earthquakes

extinct volcano

volcano that is unlikely to erupt again

cinder-cone volcanoes

volcanoes that consist primarily of erupted volcanic ash and rock fragments called cinders