Chapter 2 Honors Science

Front 1

Define fault:

Back 1

a fracture, or break, in Earth’s lithosphere, along which blocks of rock move pasteach other.

Front 2

Define stress:

Back 2

the force exerted when an object presses on, pulls on, or pushes againstanother object.

Front 3

Define earthquake:

Back 3

shaking of the ground caused by the sudden movement of large blocks ofrock along a fault.

Front 4

Define seismic wave:

Back 4

the vibrations caused by an earthquake.

Front 5

Define focus:

Back 5

the point underground where rocks first begin to move.

Front 6

Define epicenter:

Back 6

the point on Earth’s surface directly above the focus. Scientists often namean earthquake after the city that is closest to its epicenter.

Front 7

Define seismograph:

Back 7

an instrument that constantly records ground movements.

Front 8

Define aftershock:

Back 8

a smaller earthquake that follows a more powerful earthquake in the samearea.

Front 9

Define liquefaction:

Back 9

a process in which shaking of the ground causes soil to act like a liquid.(like settling when building a house, Leaning Tower of Pisa caused by settling)

Front 10

Define tsunami:

Back 10

a water wave triggered by an earthquake, volcanic eruption, or landslide.

Front 11

Define each type of fault:

Back 11

Normal fault = stress that pulls rocks apart causes normal faults; the block of rock above the fault plane slidesdown relative to the other block.

Reverse fault = stress that presses rocks together causes reverse faults; the block of rock above the fault plane movesup relative to the other block.

Strike-Slip fault = stresses that push blocks of rock horizontally cause earthquakesalong strike-slip faults; Along a strike-slip fault, blocks of rockmove sideways on either side of the fault plane.

Front 12

Define each wave:

Back 12

Primary waves (P waves) = the fastest seismic waves. These waves are the first to reach any particular location after an earthquake occurs. They travel at an average speed of 3 mi/s and can travel through solids, liquids, and gases. (Longitudinal or compression waves)

Secondary waves (S waves) = are the second seismic waves to arrive at any particular location after an earthquake, though they start at the same time as primary waves. They travel through Earth’s interior at about half the speed of P waves. They can travel through rock, but not through liquids or gases. S waves rock small buildings back and forth as they pass. (Transverse waves)

Surface waves = seismic waves that move along Earth’s surface, not through its interior. They make the ground roll up and down or shake from side to side. Cause the largest ground movements and the most damage. Travel more slowly than the other types of seismic waves.

Front 13

Define the richter/moment magnitude scales:

Back 13

Richter=an earthquake’s magnitude is based on how fast the ground moves at aseismic station. Developed in California during the 1930s by the scientists Charles Richter and Beno Gutenberg.

Moment Magnitude: scientists prefer to use this newer, more accurate scale.This scale is based on the total amounts of energy released by earthquakes. (Each whole step is 32 X’s as strong)

Front 14

Give techniques used to make buildings more earthquake-resistant:

Back 14

Base isolators = placed between a building and its foundation. The isolators aremade of flexible materials that are stacked in layers like pancakes.

Moat/open space = the moat, which may be covered at the surface with sidewalks and landscaping, lets the building shake more gently than the ground during an earthquake

Shear walls = add strength to a structure. These walls contain steel supports and are often built around a stairwell or an elevator shaft. These walls make up a part of the building known as the shear core.

Cross braces = pairs of braces that form an X shape. They help a structure keep its shape while it is being shaken.