Faults and Boundaries
Explosive and Nonexplosive Eruptions
Volcanic Cones
Volcanic Landforms and Waves
Scales and Clines
100
It causes the the hanging wall to move down relative to the footwall. They usually occur when tectonic forces cause tension that pulls rock apart.
What is a normal fault.
100
These are the most common types of eruptions. They produce relatively calm flows of lava. These eruptions can release huge amounts lava.
What is a nonexplosive eruption.
100
What are the three types of volcanic cones?
1. Shield 2. Cinder 3. Composite
100
They form around the central vent at the top of many volcanoes. During less explosive eruptions, lava flows and pyroclastic material can pile up around the vent creating a cone with this. As the eruption stops, the lava that is left in this often drains back underground. The vent may then collapse to form a larger one. If the lava hardens in this, the next eruption may blast it away. In this way, it becomes larger and deeper.
What is a crater.
100
Throughout much of the 20th century, seismologists used this to measure the strength of earthquakes. Seismologist Charles Richter created this in the 1930s. Richter wanted to compare earthquakes by measuring ground motion recorded by seismograms at seismograph stations. 2.0 can be detected only by seismograph 3.0 can be felt at epicenter 4.0 can be felt by most people in the area 5.0 causes damage at epicenter 6.0 can cause widespread damage 7.0 can cause great, widespread damage
What is the Richter Scale.
200
It causes the hanging wall to move up relative to the footwall. Usually happens when tectonic forces cause compression that pushes rock together.
What is a reverse fault.
200
However, the effects of these eruptions can be incredibly destructive. During these eruptions, clouds of hot debris, ash, and gas rapidly shoot out from a volcano. Instead of producing lava flows, they cause molten rock to be blown into tiny particles that harden in the air. The dust-sized particles, called ash, can reach the upper atmosphere and can circle the Earth for years. Larger pieces of debris fall closer to the volcano. Thes eruptions can also blast millions of tons of lava and rock from a volcano. In a matter of seconds, they can demolish an entire mountainside.
What is and explosive volcano.
200
Explain each cone.
SHIELD-Built of layers of lava released from repeated nonexplosive eruptions. Because the lava is very runny, it spreads out over a wide area. Over time, the layers of lava create a volcano that has gently sloping sides. Although their sides are not very steep, shield volcanoes can be enormous. CINDER- Made of pyroclastic material usually produced from moderately explosive eruptions. The pyroclastic material forms steep slopes. They are small and usually erupt for only a short time. Paricutín appeared in a cornfield in 1943 and erupted for only nine years before stopping at a height of 400 m.They often occur in clusters, commonly on the sides of other volcanoes. They usually erode quickly because the pyroclastic material is not cemented together. COMPOSITE-Sometimes called stratovolcanoes, are one of the most common types of volcanoes. They form from explosive eruptions of pyroclastic material followed by quieter flows of lava. The combination of both types of eruptions forms alternating layers of pyroclastic material and lava. They have broad bases and sides that get steeper toward the top.
200
They can appear similar to craters, but they are many times larger. These are large, semicircular depression that forms when the chamber that supplies magma to a volcano partially empties and the chamber’s roof collapses. As a result, the ground above the magma chamber sinks
What is a caldera.
200
A measure of the degree to which an earthquake is felt by people and the amount of damage caused by the earthquake, if any, is called intensity. Currently, seismologists in the United States use this to measure earthquake intensity. This is a numerical object that uses Roman numerals from I to XII to describe increasing earthquake intensity levels. An intensity level of I describes an earthquake that is not felt by most people. An intensity level of XII indicates total damage of an area. Because the effects of an earthquake vary from place to place, any earthquake will have more than one intensity value. Intensity values are usually higher near an earthquake’s epicenter.
What is the Mercalli Scale.
300
They form when opposing forces cause rock to break and move horizontally. If you were stanfing on one side of this when it moved, the ground on the other side would appear to move to your left or right.
What is a strike-slip fault.
300
Lava's ability to flow. Lava with a high amount of this is stiff. Lava that has a lower amount of this is more fluid.
What is viscosity.
300
A volcano that is effectively "sleeping"/waiting for its next time to erupt.
What is a dormant volcano.
300
In this type of eruption, runny lava can pour out for millions of years and spread over huge areas. This is a landform that results from repeated eruptions of lava spread over a large area.
What is a lava plateau.
300
Up-ward folds.
What are anticlines.
400
What are the three types of boundaries?
1. Convergent 2. Divergent 3. Transform
400
During an eruption, molten rock, or magma, is forced to the Earth’s surface. Magma that flows onto the Earth’s surface is called this. Volcanoes are areas of Earth’s surface through which magma and volcanic gases pass.
What is lava.
400
A volcano that can erupt at any time.
What is an active volcano.
400
Explain P-waves and S-waves.
P-WAVES: Seismic waves that causes particles of rock to move in a back-and-forth direction. S-WAVES: Seismic waves that cause particles of rock to move in a side-to-side direction.
400
Downward, troughlike folds.
What are synclines.
500
What happens at each boundary?
CONVERGENT-Two plates collide and the oceanic crust is subducted under the continental crust because the oceanic crust is denser and thinner than continental crust. DIVERGENT-Two plates drift away from each other and form rift valleys, mid ocean ridges, and undersea trenches. TRANSFORM-Two plates slip past each other and grind and jerk as they slide. This produces earthquakes.
500
If this content of magma is high, an explosive eruption is more likely. Because magma is underground, it is under intense pressure and water stays dissolved in the magma. If the magma quickly moves to the surface, the pressure suddenly decreases and this and other compounds, such as carbon dioxide, become gases. As the gases expand rapidly, an explosion can result.
What is water content.
500
A volcano that will never erupt again.
What is an extinct volcano.
500
Explain seismic waves and surface waves.
SEISMIC WAVES- Waves of energy that travel through the Earth, away from an earthquake in all directions. SURFACE WAVES- Move along the Earth’s surface and produce motion mostly in the upper few kilometers of Earth’s crust. There are two types of surface waves. One type of surface wave produces motion up, down, and around. The other type produces back-and-forth motion like the motion produced by S waves. Surface waves are different from body waves in that surface waves travel more slowly and are more destructive.
500
In a this, rock layers are folded so that both ends of the fold are horizontal. Imagine taking a stack of paper and laying it on a table. Think of the sheets of paper as different rock layers. Now put a book under one end of the stack. You can see that both ends of the sheets are horizontal, but all of the sheets are bent in the middle.
What are monoclines.
M
e
n
u