Earthquake tips (Earthquake engineering)

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Learning Earthquake Design and construction (TIPS 2)


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Learning Earthquake Design And Construction (Earthquake Tip 2):

Learning Earthquake Design And Construction (Earthquake Tip 2) Prepared By :- Amardeep Gohel Sangeeta Sanghani Divyesh Bharkhada

Introduction Of Earthquake :

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 :

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 :

How it occurs Earthquake

Seismic Waves :

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 :

Arrival of Seismic Waves at site

Type of Seismic Waves :

Type of Seismic Waves

Primary 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 :

Primary Wave

Secondary 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 :

Secondary Wave

Body 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 V P ~ 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 V S ~ 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 :

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 :

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 :

Love Wave

Rayleigh 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 :

Rayleigh Wave

surface Wave :

surface Wave L,  Love, Surface waves, Long waves Transverse horizontal motion, perpendicular to the direction of propagation and generally parallel to the Earth’s surface V L ~  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 V R ~  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 :

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 wave

Spreading of body wave :

Spreading of body wave

Vidio and softwer tutorial :

Vidio and softwer tutorial Sesmic wave effect on stru . vidio C link\ 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 :

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 :

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 :

Schematic of seismographs

Working principal seismographs :

Working principal seismographs Pen attach at bottom of pendulum, Drum rotate at constant speed, magnet provide for control of damping. Seismoscopes :- “ W hich 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 :

Measurement in X, Y, Z Direction

Error in seismograph :

Error in seismograph

Sample of seismogram :

Sample of seismogram

Sample of seismogram :

Sample of seismogram

Magnitude :

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 :

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 :

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 :


Thank to all of you :

Specially thanks to Pro. Mazar Dhankot Pro. Dipesh Rathod Thank to all of you

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