The Science of Natural Disasters
, 7th ed., by Patrick L. Abbott (New York: McGraw-Hill, 2009;
Written Assignment 1
1. Distinguish between the theories of continental drift and plate
tectonics. What lines of evidence are used to support each theory?
The continental drift, were the continents drifted apart from each. Evidence
being, where Africa and South America look as though they could fit together.
Scientists believe they were connected at one point, but drifted apart due to
the tectonic plates rupturing, creating volcanoes which have produced rock
increasing their separation over time. Scientists also believe these continents
will eventually be rejoined.
Wegener hypothesized that there was an original, super-continent 200 million
years ago, which he named Pangaea (all earth), consisting of all of Earth's
landmasses. Wegener believed the super continent existed from the Permian
through the Jurassic periods and began to break during the Jurassic period,
forming continents. These drifts form our current earth, changing the map on
a continuous basis.
The tectonic plates; soon after the earth was formed billions of years ago, it
was formed with an earths crust.
Formed of rock 50 to 200 miles thick, they
float upon a soft mantle. Over time this crust (rock) cracked continuing to
float, moving horizontally as well as vertically.
Over time, the rock as
changed form, adding rock while pieces also break off.
The continental drifts are the continents on top of the tectonic plate, which
drift over time while volcanic action creates more land mass. The underlying
plates continue their movement, while the plates change in size. The sea
levels changing over time, covering and / or exposing different amounts of
This theory was developed in the 1960’s explaining, earthquakes, volcanoes,