eng and seismic waves

Engineering Waves Overview



_{In this lesson, we will learn about:}

 _{What are waves?}

 _{What are different types of waves?}  _{How do waves travel?}

 _{How do waves relate to engineering?}



_{Our focus is on:}

Wave Basics



_{What is a wave?}

 _{A disturbance that travels through space or time, usually}

by the transfer of energy

Wave Basics



_{Important vocabulary:}

Types of Waves

 In this animation of a standing wave, the red dots represent the nodes



_{electromagnetic waves}

 _{light waves}  _{radio waves}

Seismic Waves

 _{Waves that travel through the Earth}  _{Classifications:}

 _{Body Waves}

 _{Faster, travel through the interior of the}

Earth

 _{P-waves (primary)}  _{S-waves (secondary)}  _{Surface Waves}

 _{Slower, travel along the surface of the Earth}  _{Cause more damage}

 _{Similar to water waves}  _{Love waves}

Body Waves: Primary Waves



_{P-waves cause the ground to have}

vibrations along or parallel to the

direction of the wave

 _{Fast! The first type of seismic wave to}

arrive at a point away from the epicenter

 _{Can travel through any medium}  _{Typical speeds:}

 _{In air: 330 m/s}

 _{In water: 1450 m/s}

 _{In granite: 5000 m/s}

Plane P-wave

Body Waves: Secondary Waves



_{S-waves cause the motion of the}

ground to be perpendicular to the

direction of the wave

 _{Can only travel through solids}

 _{Speed is about 60% of a P-wave in a}

material

 _{Arrives second at a point away from}

the epicenter

Plane S-wave

Surface Waves: Love Waves



_{Love waves cause}

_{horizontal shifting}

_{of the Earth during}

earthquakes

 _{Move slower than P-waves and S-waves, but faster than}

Rayleigh waves

 _{Named for A.E.H. Love, the man who predicted this type of}

Surface Waves: Rayleigh Waves



_{Rayleigh waves cause a}

_{rolling motion}

_{—like ocean waves}

 _{Slowest of the seismic waves (travel at around 3 km/s)}

 _{Produced by the interaction of P- and S-waves at the Earth’s}

surface

All Seismic Waves



_{Intensity depends on:}

 _{Size of earthquake}

 _{Distance to the earthquake}  _{Depth of the earthquake}

 _{Geological structure of the crust}



_The

_{amplitude decreases}

_{with increasing}