Earth Science Flashcards Chapter 14/15
Earthquake
A sudden movement of Earth’s crust that releases energy
Conduction
Occurs when heated molecules pass their vibrational energy to nearby molecules by direct contact
Radiation
The movement of electromagnetic energy through transparent materials
Convection
Heated matter circulates from one place to another due to differences in temperature and density
Convection Cell
Heated material rises toward the surface in some places and in other places, cool material sinks into Earth. Horizontal currents complete the circulation by connecting the areas of vertical heat flow
Stress
Forces applied to solid rock at high temperatures and over a long time can bend, or deform, rocks
Strain
Elastic bonding response to stress by surface rocks
Faults
Cracks in Earth’s crust where earthquakes occur
Focus
The place underground where the rock begins to separate of an earthquake
Epicenter
The point directly above the focus where the earthquake is fealt most
Seismology
The study of earthquakes
Mercalli Scale
Measurement of how powerful an earthquake is without instruments
Richter Scale
Measurement of earthquake magnitude with a seismograph
Seismograph
Tool used to measure the magnitude of an earthquake through the Richter Scale
Seismic Moment
Magnitude Scale based on the total energy released by the earthquake
Logarithmic
An increase of one unit on the scale translates to a 10-fold increase in the quantity measured
Primary waves
The first waves to arrive at any location
Secondary waves
Travel at about half of the speed of P-waves
Seismologists
Someone who studies the earth and attempts to foretell an earthquake
Travel time
The time inferred between the breaking of the rocks that causes an earthquake and when the event is detected at a given location
Origin Time
The time at which the fault shifted
Moho
Boundary between the crust and the mantle
Refraction
The bending of energy waves
mid-ocean ridges
An underwater system of mountain ranges
seafloor spreading
The mid-ocean ridges are the places where new lithosphere is made and adds on to older material that moves away from the ridges on both sides
Polarity
The direction of a magnetic field
Subduction Zones
Where the old lithosphere moves back into Earth’s interior
Ocean Trenches
Where the more mafic parts of the lithosphere are absorbed into the mantle
Plate Tectonics
Tectonic forces cause the rocks of the continents to become folded
Lithospheric Plates
A dozen rigid sections that makes up Earth’s surface
Lithospheric Plates
A dozen rigid sections that makes up Earth’s surface
Fluid
Any substance that can flow
Plastic
A solid under short-term stress that flows like a liquid when stress is applied over a long period of time
Asthenosphere
The plastic part of the mantle. Plastic refers to its state of matter
Divergent Plate Boundaries
At the mid-ocean ridges new ocean floor
away from the plate boundary
Convergent Plate Boundaries
Zones of Subduction
Island Arc
A curved line of volcanic islands
Transform Boundary
occurs when two plates slip past each other without creating new lithosphere or destroying old lithosphere
Hot Spot
A long-lived source of magma within the asthenosphere and below the moving lithospheric plates
