Date post: | 09-Aug-2015 |
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GEOGRAPHY
CONTENTS: ANATOMY OF AN EARTHQUAKES
THE MEASUREMENTS OF EARTHQUAKES
CONSTRUCTIVE EFFECTS OF EARTHQUAKES
ANATOMY OF AN EARTHQUAKEPOWERFUL VIBRATIONS ARE RELEASED DUE TO THE MOVEMENT OF THE EARTHS PLATES.THESE VIBRATIONS TRAVEL IN THREE TYPES OF WAVES:P-WAVES OR PRIMARY WAVESS-WAVES OR SECONDARY WAVES OR
SHEAR WAVESL-WAVES OR LONG WAVES OR SURFACE
WAVES
PRIMARY WAVESPARTICLES
VIBRATE IN THE DIRECTION OF WAVES
CAN PASS THROUGH SOLID LIGUID AND GASES
FIRST TO BE RECORDED ON SEISMOGRAPH
SECONDARY OR SHEAR WAVESPARTICLES
VIBRATE AT RIGHT ANGLES TO THE DIRECTION OF MOVEMENT OF THE WAVE
CANNOT PASS THROUGH LIQUIDS
RECORDED AFTER P WAVES ON SEISMOGRAPH
LONG OR SURFACE WAVESTRAVEL ALONG
THE SURFACE OF THE EARTH
RECORDED AFTER PRIMARY AND SECONDARY WAVES
TWO TYPES OF L WAVES ARE:LOVE WAVES AND RAYLEIGH WAVES
THE P,S AND L WAVES TRAVELTROGH THE INTERIOR OF THE EARTH
THE POINT OF ORIGIN OF THESE WAVES IS KNOWN AS THE SEISMIC FOCUS.
THE POINT ON THE EARTH DIRECTLY ABOVE THE SEISMIC FOCUS IS CALLED THE
EPICENTRE.
MEASUREMENTSSEISMOGRAPHRICHTER SCALEMERICALLI SCALE
SEISMOGRAPHTO MEASURE DIRECTION
OF MOVEMENT OF WAVESIT HAS A PEN ATTACHED
TO IT THAT RECORDS THE MOVEMENTS OF THE WAVES ON A STRIP OF PAPER.
ALSO CALCULATES THE DIFFERENCE BETWEEN THE RECORDING STATION AND EPICENTRE BY CALCULATING THE DIFFERENCE IN ARRIVAL OF P AND S WAVES.
RICHTER SCALETO MEASURE
INTENSITY (THE AMOUNT OF ENERGY RELEASED DURING AN EARTHQUAKE)
MEASURES THE POWER OF AN EARTHQUAKE ON A SCALE OF ONE TO NINE
MERICALLI SCALETO MEASURE
INTENSITY (THE AMOUNT OF ENERGY RELEASED DURING AN EARTHQUAKE)
GRADES THE EARTHQUAKES ON THE BASIS OF OBSERVED EFFECTS ON A -12 POINT SCALE
SHANSHI (CHINA -1556),830000 KILLED
KOLKATA -1737,300000 KILLED
CONSTRUCTIVE EFFECTS OF EARTHQUAKESENERGY RELEASE:
i. EARTH RELEASES ITS STORED UP ENERGY
ii. ENERGY RELEASE HELPS IN KEEPING THE EARTH IN A PROPER SHAPE
LANDFORMSIN THE OCEAN BELTS THE EARTHS CRUST MAY BE EITHER RAISED OR LOWERED DUE TO VERTICAL OR LATERAL DISPLACEMENT.
G-5 MEMBERS :1. SARITA2. SHRUTI3. AGNIBH4. SAKSHI5. SARIKA6. RUKMINI
THANK YOU!!!