Earthquakes are the tremendous vibration on the earth surface due to internal force or man made stress
Or
The geographical definition of earthquake is a series of shoke due to the sudden movement of crustal rocks generated at a point is knoen as hypocentre or sysmic focus within the crust or mandle
Monday 11 February 2013
EARTH QUAKES
ACTIVE VOLCANOES
Active volcanoes are volcanoes which can be erupted at any time
MT ST HELENA(usa)
MT STROMBOLIC(italy)
MT ETNA (italy)
VOLCANOES
A volcano is a narrow oppening IN the earth surface connected by a magma chamber through which magma rock fragment ashes lava steam flames and other gas the emmitted from the interiour of earth
ECONOMIC SIGNIFICANCE OF ROCK
Rocks are store house of minerals
Rocks provide us building stones like grinite marble
Rocks help us for the constructionof roads and dams
It help ius for the manufacturing of cement
It provides raw meterial
ROCK CYCLE
When the magma dpfound beneath the earth crust originated and flows IN the interiour and extreriour and exteriour of the earth surface which cools and solidifies to form igneous rocks,igneous rocks are the parant of other rocks
Metmorphic rocks
It is formed by the process metamorphism of pre existing rocks metamorphism means chnge of forms
DURING THIS PROCESS THE ORIGINAL MINERALS GET ULTERED AND NEW MINERALS ARE FORMED
Sedimentaery rocks
The word sedimentary is dirived from the word sedmentum means settling down
Sediment rocks are formed by the process of wethering erosion transportation and deposition of seas river ,slakes ,glaciers and wind
The sedimentary rocks are porus and permiable the cedimentation ,compaction, hardning of seddiment
IGNEOUS ROCKS
When lava pours out on the earth surface through volcanic eruption it cools and solidifies to form extrusive igneous rocks
Igneous rocks are divided into two
(1) acidic igneous rocks
(2) basic igneous rocks
THE EARTH
The earth is the third nearest planet to sun
The average distance between the sun and the earth is about 150 million km
One of the unique features of earth is atmosphere which is rich in oygen (21)% and nitrogen (78)%
+98)% of water is saline water (3)% is pure water
SHAPE OF THE EARTH
Millions of years ago.........
The shape was considered as flat
After that it proved to be sperical
IF THE EARTH WAS FLAT ALL PLACE ON THE EARTH WOULD HAVE SUN RISE AND SUNSET AT THE SAME TIME BUT THE FACT IS THAT THE RISING SUN IS SENN AT THE IST PLACE THAT IS EAST and THEN PLACES ON WEST SO IT PROVIDE THAT EARTG IS SPERICAL IN SHAPE