the mid-ocean ridge
This is the place on the ocean floor where scientists found the youngest samples of dating core.
The ocean floor is pushed outward by the formation of new crust at the site of a mid-ocean ridge. Older crust is pushed down into trenches. This pushing outward is called this.
(true or false) Some minerals act like magnets. When these minerals form, their magnetic properties are set and cannot be changed.
(true or false) Mid-ocean ridges form some of the longest and highest mountain chains in the world.
the Rift Valley
In the center of the underwater mountains is a deep slit where many lava eruptions occur. This slit is called this.
These boundaries are called destructive boundaries. They form when the crust of one plate is pushed downward into a trench, becoming molten rock.
This boundary forms when one plate slides horizontally past another one. This sliding is not easy. The plates grind one another abrasively as they move.
This is also called a constructive boundary, and is formed at a rift valley. This is the site of two plates that are moving apart from one another.
ring of fire
Colliding plates at destructive boundaries result in tremendous tension, pressure, and friction. There is so much tension that the Pacific Plate is circled by this as a result of these collisions.
(true or false) Most volcanoes occur along transform boundaries.
(true or false) The San Andreas fault is located in the state of Missouri.
These are caused by the movement of faults. Faults are breaks in crust plates that move past one another. This movement could be either vertical, horizontal, or both.
Sometimes the blocks of the lithosphere on either side of a fault line "lock up" and motion is stopped. Pressure and tension builds until the faults break apart and suddenly move past one another. This movement begins deep within the earth at a point called this.
If you drew a line straight up from the focus to the surface of the earth, this would indicate where the greatest motion is felt during an earthquake.
The movement of the faults produces energy waves that are called this.
This is a sceintific device used to measure the intensity of an earthquake.
These are the fastest of the waves that are sent out from an earthquake. They originate in the focus and move outward through all states of matter. They can cause back and forth motion in matter.
These waves are slower that the P-waves. They originate at the focus and pass only through solids, causing movement from side to side.
These waves are surface waves. They are the slowest of the three wave types. These waves affect the surface of the land by causing it to rise and fall like waves on an ocean.
When an earthquake occurs on the ocean floor, it can cause a huge tidal wave which is called this.
This is the name given to the theory that the continents were once one great land mass and have since drifted to their present locations.
This forms or happens when two continental plates collide.
new crust formation
This is one thing that does not happen in the Rift Valley.
(true or false) The boundary of the San Andreas fault is a transform boundary.
An earthquake that was rated a 3 on the Richter scaled would be ______.