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!!!