Plate Tectonics & Effects of Plate Movements

Theory of Plate Tectonics

states that all the Earth’s continents at one time were joined as a single “super continent” called Pangaea. over time, the continents drifted apart

Puzzle Piece Argument

the coastlines of all the continents would fit together like a puzzle piece

for example, the west coast of Africa would fit perfectly into the east coast of South America

What factors all support the idea of continental drift?

seafloor spreading, the puzzle piece argument, and fossil records

seafloor spreading

for example, the Atlantic seafloor is year after year moving slowly apart. Lava comes up between plates, when it hits the water, it hardens, breaks apart again and keeps moving apart.

fossil records

for example, certain fossils in the east coast of South America can only be found elsewhere on the West Coast of Africa.

what do shifting plates cause?

earthquakes, mountains and volcanoes

Plate movement occurs along three major fault types:

convergent, divergent and transform

Convergent

plates that push together upwards forming mountains

eventually one plate goes under the other, which is what causes some mountains to have a higher point and a lower point

Divergent

plates pulling apart, ie Atlantic sea floor

Transform

sliding past one another

slipping and sliding of plates causes

earthquakes

“Ring of Fire”

the region of the earth that surrounds the Pacific Plate (the plate under the pacific ocean), thats why along the West Coast of the US and the East Coast of Asia, there are many volcanoes and earthquakes

Why do certain areas experience more quake damage than others?

has to do with how solid the ground underneath the buildings is

hard ground = less damage

this is why softer areas along the shore tend to suffer more

volcanic eruptions can be…

predicted in time to evacuate residents

signs:

• bulge on the side of the mountain can indicate magma buildup

• seismic activity

how to mitigate earthquake damage

happen suddenly and are unpredictable

their damage can be mitigated through a combination of geological knowledge, construction engineering and general preparedness