The surface of the earth is divided into seven very big and also with some small moving plates. Each plate is about 50 miles thick! These plates move a few inches a year. There is three types of movements they are - convergent, divergent, and transform. When an oceanic plate collides with a continental plate, the oceanic plate digs under the continental plate this makes an ocean trench. Plates also can move away from each other like they do in the Mid-Atlantic Ridge. Where plates move there is a hot molten rock that rises and cools making new rock at the edges of the oceanic plate. this is called the sea-floor spread.
Wagner was not the first to notice these puzzle like pieces Magellan and other explorers noticed these on their maps. Palaeontologists noticed fossils of similar species on different continents that now are separated.
Waggoners "Continental Drift" theory was later disproved . It was one of the first times crust movement had been brought to the Scientific community. Years went by and more and more evidence was found to support the idea of the continents over time.
Techtionic Earthquakes , volcanos earthquakes , collapse earthquakes, explosion earthquakes along the fault 2 plates move in opposite directions large earthquakes occur when 2 plates rub together or when one plate pushes the other . The faults are long deep cracks that split the earths crust into parts . earthquakes happen when these parts shift usually the rock on either side of the fault moves slowly and steadily. But at some places along a fault gets locked together . movement stops in those places but continues in others along the fault.
The earthquakes starts at a place in the bedrock called the focus . The epicentre is the place above the focus, near the earths surface . Shock waves spread threw out the earth surface or the bedrock in all directions , the most violent shaking is at the epicentre. Earthquakes are caused when plates move , rub or push against each other .The earths crust is made up of 7 major plates and 13 smaller ones. The plates float on magma . Since the plates are floating they can slowly move. The place where 2 or more plates meet is called the fault line.
There are four different types of earthquakes such as Tectonic , Volcanic and Explosion. The type of earthquakes usually depends on the area where is occurs and the type of land in the region. The most common earthquakes are "Tectonic." They occur when the rocks in the Earth crust break or crack because the lands forces made up by the movement of tectonic plates. Another type is called "Volcanic earthquakes . This type occurs the same as volcanic activity . also there is the "Collapse earthquakes" Which are small earthquakes in underground caverns and mines . Then there are "Explosion "earthquakes which result from an explosion of nuclear devils . People can measure motion from large tectonic earthquakes .
This is a picture of the Armenian earthquakes that took place on December 7, 1998.The amount of magnitude released according to the Richter scale was 6.9 and it was also followed by an aftershock of 5.8 after only 4 minutes. Unfortunately this was not the only earthquakes that took place in this area .The Armenian earthquakes was followed by dozens of other quakes over the next couple of months that followed . The quakes and aftershocks caused tens of thousands of deaths and injuries, it also left half a million people homeless.
