EARTHQUAKE Presentation [TIPS 2]
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Transcript of EARTHQUAKE Presentation [TIPS 2]
LEARNING EARTHQUAKE DESIGN
AND CONSTRUCTION(EARTHQUAKE TIP 2)
Prepared By :- Amardeep GohelSangeeta SanghaniDivyesh Bharkhada
INTRODUCTION OF EARTHQUAKE
What is EQ. :- sudden movement or shaking of the Earth is Known as Earthquake.
Why occurs:-Caused by: plate tectonic stresses, volcanic or magmatic activity
Where:- Located at plate boundaries 1) Extra Plate Earthquake 2) Intra Plate Earthquake
Large ‘Strain Energy’ released during Earthquake.
Stress= P/A Strain=∆L/L
HOW IT OCCURS EARTHQUAKE
Reason Of Earthquake :- 1) Stick-slip motion {Compare to stuck door}
2) Friction(Resists to a slip) 3) Lithosphere plate have
many section
HOW IT OCCURS EARTHQUAKE
SEISMIC WAVES
Seismic waves are the vibrations from earthquakes, that travel through the Earth.
Different Kind of seismic waves, and they move in different ways. The two main type of waves are Body Wave And Surface Wave.
Body Wave:- Travel through the Earth’s interior
Surface Wave:-Move along the earth’s surface. ( Similar to ocean waves )
ARRIVAL OF SEISMIC WAVES AT SITE
TYPE OF SEISMIC WAVES
Seismic Wave
Body Wave
P-Wave
S-Wave
Surface Wave
Love Wave
Rayleigh wave
PRIMARY WAVE
Is Also known as Compressional Wave, Longitudinal Wave.
Can Pass Through Rock Can pass through a Liquid It pushes and pulls the rock. It moves through just like sound wave
push and pull the air. Higher velocity (6 Km/Sec in the crust)
PRIMARY WAVE
SECONDARY WAVE
S wave move the ground up and down or side to side.
S Wave oscillate at right angle to it.(like snake)
S-wave do not travel through fluids, so do not exist in earth’s outer core.(move only solid)
S-wave travel slower then P wave in a solid. Therefore, arrive after the P wave.
Transverse or shear wave.
SECONDARY WAVE
BODY WAVE
Table : Seismic Waves
Type (and names)
Particle Motion Typical Velocity Other Characteristics
P,Compressional, Primary, Longitudinal
Alternating compressions (“pushes”) and dilations (“pulls”) which are directed in the same direction as the wave is propagating (along the ray path); and therefore, perpendicular to the wave front
VP ~ 5 – 7 km/s in typical Earth’s crust; >~ 8 km/s in Earth’s mantle and core; 1.5 km/s in water; 0.3 km/s in air
P motion travels fastest in materials, so the P-wave is the first-arriving energy on a seismogram. Generally smaller and higher frequency than the S and Surface-waves. P waves in a liquid or gas are pressure waves, including sound waves.
S, Shear, Secondary, Transverse
Alternating transverse motions (perpendicular to the direction of propagation, and the ray path); commonly polarized such that particle motion is in vertical or horizontal planes
VS ~ 3 – 4 km/s in typical Earth’s crust; >~ 4.5 km/s in Earth’s mantle; ~ 2.5-3.0 km/s in (solid) inner core
S-waves do not travel through fluids, so do not exist in Earth’s outer core (inferred to be primarily liquid iron) or in air or water or molten rock (magma). S waves travel slower than P waves in a solid and, therefore, arrive after the P wave.
SURFACE WAVE
Move along the Earth’s surface Produces motion in the upper crust
Motion can be up and down Motion can be around Motion can be back and forth
Travel more slowly than S and P waves More destructive
LOVE WAVE
The first kind of surface wave is called a Love wave.
L-wave named after A.E.H. Love, a British mathematician who worked out the mathematical model for this kind of wave in 1911.
It's the fastest surface wave and moves the ground from side-to-side.
LOVE WAVE
RAYLEIGH WAVE
The other kind of surface wave is the Rayleigh wave. named for John William Strutt, Lord Rayleigh, who mathematically predicted the existence of this kind of wave in 1885.
A Rayleigh wave rolls along the ground just like a wave rolls across a lake or an ocean. Because it rolls, it moves the ground up and down, and side-to-side in the same direction that the wave is moving
More shaking and more damage.
RAYLEIGH WAVE
SURFACE WAVEL, Love, Surface waves, Long waves
Transverse horizontal motion, perpendicular to the direction of propagation and generally parallel to the Earth’s surface
VL ~ 2.0 - 4.5 km/s in the Earth depending on frequency of the propagating wave
Love waves exist because of the Earth’s surface. They are largest at the surface and decrease in amplitude with depth. Love waves are dispersive, that is, the wave velocity is dependent on frequency, with low frequencies normally propagating at higher velocity. Depth of penetration of the Love waves is also dependent on frequency, with lower frequencies penetrating to greater depth.
R, Rayleigh, Surface waves, Long waves, Ground roll
Motion is both in the direction of propagation and perpendicular (in a vertical plane), and “phased” so that the motion is generally elliptical – either prograde or retrograde
VR ~ 2.0 - 4.5 km/s in the Earth depending on frequency of the propagating wave
Rayleigh waves are also dispersive and the amplitudes generally decrease with depth in the Earth. Appearance and particle motion are similar to water waves.
WAVE DEMO IN TANK
A simple wave tank experiment – a ping pong ball is dropped onto the surface of the water; small floats aid viewing of the waves; distance marks on the bottom of the container allow calculation of wave velocity.
SPREADING OF WAVE
SPREADING OF BODY WAVE
VIDIO AND SOFTWER TUTORIAL
Sesmic wave effect on stru. vidio Clink\Sesmok
wave effect on structure.avi softwer for how to spreed wave
How meny walkeno and eathquke from 1960.
C:\Users\Amar Gohel\Desktop\1\Smithsonian Fasttrak.lnk
VIDIO AND SOFTWER TUTORIAL
With plate eathquak counter C:\Users\Amar Gohel\Desktop\1\Seismic
Eruption.lnk Slinky effect C:\Users\Amar Gohel\Desktop\1\sliky
efect on building.avi IRIS Sismogrph have 2 vidio with dempar C:\Users\Amar Gohel
\Desktop\1\IRIS Seismographs in Schools - Seismometers.MP4
MEASURING INSTRUMENT
Seismographs record earthquake wave. Seismographs show :-
-Amplitude of seismic wave (how much rock moves or vibrate) -Distance from epicenter-Earthquake direction
Three Component:- 1)sensor:-Pendulum mass, string, magnet, support.2)recorder:-Drum, pen, chart paper.3)timer:-motor of the rotating drum at constant speed
SCHEMATIC OF SEISMOGRAPHS
WORKING PRINCIPAL SEISMOGRAPHS
Pen attach at bottom of pendulum, Drum rotate at constant speed, magnet provide for control of damping.
Seismoscopes :- “Which instrument do not have a timer device, drum dose not rotate measured only maximum intensity they are called sieismoscopes.”
Digital Instrument :- AS-1 Seismometer, EQ-1, EAI S102, SEP etc. . .
MEASUREMENT IN X, Y, Z DIRECTION
ERROR IN SEISMOGRAPH
SAMPLE OF SEISMOGRAM
SAMPLE OF SEISMOGRAM
MAGNITUDE
Richter scale:- measures the Magnitude (energy released) of the earthquake…(multiples of 10)
INTENSITY
Mercalli Scale:- rates the earthquake based on the amount of damage done…measures the intensity (1 – 12)
COMPARISON
STRONG GROUND MOTION
Seismic wave arrive at varies instant of the time, have different amplitude and carry a different level of energy.
Represented as intensity v/s time. However, engineering point of view
strong motion can be possible damage structure are of interest.
CHARACTERISTIC OF STRONG GROUND MOTION
Described in terms of displacement, velocity or acceleration.
The variation of ground acceleration with time recorded at a point on ground during an earthquake is called an accelerogram.
They denote ground shaking, peak amplitude, duration of strong shaking, frequency ,(e.g., amplitude of shaking associated with each frequency) and energy content (i.e., energy carried by ground shaking at each frequency).
ACCELEROGRAMS
Specially thanks toPro. Mazar DhankotPro. Dipesh Rathod
THANK TO ALL OF YOU