Science CH 2
Card Set Information
Science CH 2
Abeka Science CH 2, 8th grade
What part of the earth is the Mohorovicic discontinuity?
boundary between the crust and the mantle
Term for the structure formed when a layer of rock breaks and moves?
Term for deposits of sand, mineral fragments and organic material that cover most of Earth's surface?
Area where the upper mantle and the lower mantle merge?
center part of the earth
Structure formed by the bending of rocks under great force?
Name the three major layers of the earth, based on composition?
The most abundant element in the earth's crust?
Theory for the idea that the earth's crust consists of huge plates that slowly drift over the earth's surface?
Theory of plate tectonics
Name the type of fold in which the rock layers buckle upward into an archlike structure?
Term for study of earthquakes.
Name the fastest type of earthquake waves.
Smaller earthquakes that follow a large earthquake for days or weeks.
Name for the sudden movement of rock masses as a result of tectonic earthquakes.
Name the major strike-slip fault in western California.
San Andreas Fault
The slowest earthquake waves?
Name for giant sea waves caused by earthquakes.
Name of the place on the earth's surface directly above where an earthquake begins.
What is produced by rocks along a fault that may have been polished smooth?
Name for the idea that rocks on either side of a fault spring back to a position of little or no strain as the moment of and earthquake, also causing vibrations in the earth's crust.
A scale that measures earthquake strength based on it's effects on people and buildings.
Modified Mercalli Scale
Most famous scale used to measure earthquake strength?
Richter magnitude scale
Most reliable method to mathematically measure earthquakes strength?
moment magnitude scale
fixed-base system key points
1. building attached to bedrock
2. building frame & joints absorb earthquake energy
3. Negative = building deformed
1. device added to structures to absorb seismic energy?
2. lessens stress on building
3. minimizes deformation
base-isolated system key points
1. Most common new construction
2. Building is on stiltlike isolators
3. Separates building from the foundation and absorbs seismic energy
The facts about the circum-Pacific belt?
1. The most active earthquake zone?
2. Included San Andreas Fault
3. 80% world's earthquakes
Earthquake belt that stretches from northern Africa, through southern Europe and Asia, to Indonesia?
Type of fault where rocks along one side of the fault move horizontally along the fault?
Narrow zone of active volcanoes nearly encircling the Pacific basin making up more than 1/2 the worlds volcanoes?
Ring of Fire
Instrument used to record vibrations by earthquakes?
The study of the earth?
Term that all present-day continents are thought to have been one land mass?
Type of earthquake caused by sudden movements of rock beneath the earth's surface?
Mountain formed when molten rock collects beneath overlying rock layer, forcing the layer upward into a blisterlike structure?
Mountain formed when rocks on one side of fault are forced upward and the rocks on other side are forced downward?
Mountain formed when molten rock erupts from a hole in earth's crust?
Mountain formed when two rock layers push together, causing layers to buckle?
Where are the effects of an earthquake most severe?
Type of fault when rocks on one side of fault are shoved on top of the rocks on other side?
Type of fault where rocks along one side of the fault sink vertically?
Name the boundary line between the crust and the mantle?
Mohorovicic discontinuity (Moho)
Molten rock in reservoir beneath the surface?
Scientist who studies volcanoes and related phenomena.
Volcanic rock that forms when lava is emitted underwater?
Channel which a volcano ejects gases, ash, and rock from the earth's interior.
Name for gently sloping volcano that pours out large quantities of lava in mild eruptions?
Name for volcano that will probably not erupt again.
What type of large volcanic ejecta forms when liquid or semiliquid lava is thrown high into the air and hardens before hitting the ground?
Name the smallest type of solid volcanic ejecta.
What is the source of the volcanic eruption?
What forms by molten lava that leaves an empty channel after an eruption ceases?
lava tunnel of lava tubes
What is formed by large amounts of magma that solidify?
Name of the sheetlike igneous intrusion formed when magma hardens into a vertical crack?
Name of the domelike igneous intrusion that forms when magma bulges overlying rock upward.
What is larger; batholiths or laccoliths
85% of all earthquakes are what type?
Name for a bowl-shaped hollow 2 miles wide, formed by the collapse of an underground magma chamber.
Name of a large almond/teardrop shaped piece of ejecta formed when lava solidifies.
What is the inner core of the earth thought to be?
Type of volcano consisting of erupted volcanic ash and rock fragments held loosely together?
Type of volcano that is broad, gently sloping with large quantities of highly fluid lava that hardened into rock.
Type of volcano formed partly by explosive eruptions of ash and rock fragments and partly by mild lava flows.
Term for a particle or block of solid volcanic ejecta.
Name for lava that hardens into a smooth-textured rock with a "ropy" appearance.
Name for lava that hardens into rough, jagged rocks with crumbly or "blocky" texture.
Name for a superheated, incandescent cloud as gas and volcanic ash that flows swiftly down a volcanic slope.