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 are Transform Boundaries?
"This Dynamic Earth:
The Story of Plate Tectonics"
By W. Jacuelyne Kious and
Robert I. Tilling
Transform Boundaries happen when two tectonic plates are sliding past each other in opposite directions.
To illustrate this, think of two cars passing each other on a two lane road; one going one direction and the other the opposite direction. Now, what would happen if both cars rubbed against each other as they passed?
As tectonic plates slide past each other they grind and have pieces of rock that snag upon the other, this is what builds the tension between the plates and when they finally release the result is an earthquake. If there wasn't any friction or tension between them, the two plates would slide past each other without being noticed on the surface (except for the sidewalks and streets no long lining up in a straight line).
This actually happens in one area of California (between Los Angeles and San Francisco) along the San Andreas Fault. In this area the boundaries of the two plates consist of Talc (think of talcum powder that is used on babies bottoms) which allows the plates to glide past each other with ease. It is this sliding that creates the tension on the fault line to the north (San Francisco) and to the south (Los Angeles) where the boundaries of the fault is Granite which is a dense jagged rock which caused the two plates to snag and catch on each other. The release of the tension in the Granite is what results in the earthquakes in this region (The Science of Earthquakes; History Channel, 2007, clip of this 1 hour video is shown here).
The diagram above depicts the many Transform Boundaries in the Pacific Ocean and North America.
To learn more about Transform Boundaries go to the National Geological Society website by clicking here.
To return to the types of earthquakes, click here.
To illustrate this, think of two cars passing each other on a two lane road; one going one direction and the other the opposite direction. Now, what would happen if both cars rubbed against each other as they passed?
As tectonic plates slide past each other they grind and have pieces of rock that snag upon the other, this is what builds the tension between the plates and when they finally release the result is an earthquake. If there wasn't any friction or tension between them, the two plates would slide past each other without being noticed on the surface (except for the sidewalks and streets no long lining up in a straight line).
This actually happens in one area of California (between Los Angeles and San Francisco) along the San Andreas Fault. In this area the boundaries of the two plates consist of Talc (think of talcum powder that is used on babies bottoms) which allows the plates to glide past each other with ease. It is this sliding that creates the tension on the fault line to the north (San Francisco) and to the south (Los Angeles) where the boundaries of the fault is Granite which is a dense jagged rock which caused the two plates to snag and catch on each other. The release of the tension in the Granite is what results in the earthquakes in this region (The Science of Earthquakes; History Channel, 2007, clip of this 1 hour video is shown here).
The diagram above depicts the many Transform Boundaries in the Pacific Ocean and North America.
To learn more about Transform Boundaries go to the National Geological Society website by clicking here.
To return to the types of earthquakes, click here.