The above photo is of the Emporeum and James Flood Building after the 1906 San Francisco earthquake (the virtual museum of the City of San Francisco).
What Really Causes Earthquakes?
"This Dynamic Earth:
The Story of Plate Tectonics"
By W. Jacuelyne Kious and
Robert I. Tilling
We think of the earth as being solid, while only the top 100 kilometers (or 62.13 miles) of the earth comprised of solid materials. To put that in perspective, that is the distance between Milwaukee and Green Bay; only verticle. The rest of the earth's 6,278 kilometers (or 3,900 miles) from core to the surface is liquid or mostly liquid elements (National Geological Society, source link here).
This means that the land we walk upon is floating on the surface of a ball of molten materials which comprise the majority of the planet. Like anything that floats, the crust and upper mantle (known as the Lithosphere) are moving upon a ball shaped ocean.
Now let's take a closer look at the movement of the crust upon this molten sphere.
This means that the land we walk upon is floating on the surface of a ball of molten materials which comprise the majority of the planet. Like anything that floats, the crust and upper mantle (known as the Lithosphere) are moving upon a ball shaped ocean.
Now let's take a closer look at the movement of the crust upon this molten sphere.
The movement of the Earth's crust
"This Dynamic Earth:
The Story of Plate Tectonics"
By W. Jacuelyne Kious and
Robert I. Tilling
The earth's crust is made up of a dozen or more
large and small plates that rub against each other as they are moved by the liquid materials beneath them. This explanation is called the 'theory of plate tectonics'. It states that earthquakes result from the plates of the earth moving into and away from each other (National Geological Society, 'This Dynamic Earth: the story of plate
techtonics; by Jacuelyne Kious and Robert I. Tilling; source link here).
The graphic here, shows the movement of these plates over the past 250 million years. As you can see, the earth looked very different than it does today when you look at a map or globe (National Geological Society, 'This Dynamic Earth: the story of plate techtonics; by Jacuelyne Kious and Robert I. Tilling; source link here)
These changes have taken place slowly, over a
great many years. Yet, the earth's plates continue to shift and change, colliding with and separating from each other. Thus changing the shape of mountains, continents and the distance of the oceans that separate them.
For more information about plate tectonics, go to the United States Geological Society's website.
Now, Let's take a look at the types of boundaries tectonic plates have by clicking here.
large and small plates that rub against each other as they are moved by the liquid materials beneath them. This explanation is called the 'theory of plate tectonics'. It states that earthquakes result from the plates of the earth moving into and away from each other (National Geological Society, 'This Dynamic Earth: the story of plate
techtonics; by Jacuelyne Kious and Robert I. Tilling; source link here).
The graphic here, shows the movement of these plates over the past 250 million years. As you can see, the earth looked very different than it does today when you look at a map or globe (National Geological Society, 'This Dynamic Earth: the story of plate techtonics; by Jacuelyne Kious and Robert I. Tilling; source link here)
These changes have taken place slowly, over a
great many years. Yet, the earth's plates continue to shift and change, colliding with and separating from each other. Thus changing the shape of mountains, continents and the distance of the oceans that separate them.
For more information about plate tectonics, go to the United States Geological Society's website.
Now, Let's take a look at the types of boundaries tectonic plates have by clicking here.