Tectonic Hazards Flashcards
Types of plate boundaries
constructive, tensional: two plates move away from each other
destructive, compressional: plates of oceanic crusts move toward plates of continental crust
collision: two plates of continental crust move together
conservative: two plates slide past each other
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Location of tectonic hazards
Plate boundaries are the location of tectonic hazards
Cause and effects of volcanoes: named example
Cause: pressure builds up inside the volcano and blasts the lava plug until it erupts with ash and lava
Effect: Lava can destroy anything in its path, ash cloud can affect air travel and air quality
Named example: Eyjafjallajokull, Pompeii, Montserrat
Cause and effects of earthquakes: named example
Cause: Plates rub together, pull apart or slide under one another to create an earthquake
Effect: Damage to homes and buildings, other structures, can cause tsunamis
Named example: San Andreas fault, Northridge Earthquake 1994
How are earthquakes measured
Two different scales:
The Richter scale: A single number that measures the amount of energy released by an earthquake. It is on a logarithmic scale, gets worse by degrees.
The Mercalli Scale: A range of figures that reflect the damage caused by the earthquake in different areas such as:
I. Instrumental Generally not felt by people unless in favorable conditions.
II. Weak Felt only by a couple people that are sensitive, especially on the upper floors of buildings. Delicately suspended objects (including chandeliers) may swing slightly.
III. Slight Felt quite noticeably by people indoors, especially on the upper floors of buildings. Many do not recognize it as an earthquake. Standing automobiles may rock slightly. Vibration similar to the passing of a truck. Duration can be estimated. Indoor objects (including chandeliers) may shake.
IV. Moderate Felt indoors by many to all people, and outdoors by few people. Some awakened. Dishes, windows, and doors disturbed, and walls make cracking sounds. Chandeliers and indoor objects shake noticeably. The sensation is more like a heavy truck striking building. Standing automobiles rock noticeably. Dishes and windows rattle alarmingly. Damage none.
V. Rather Strong Felt inside by most or all, and outside. Dishes and windows may break and bells will ring. Vibrations are more like a large train passing close to a house. Possible slight damage to buildings. Liquids may spill out of glasses or open containers. None to a few people are frightened and run outdoors.
VI. Strong Felt by everyone, outside or inside; many frightened and run outdoors, walk unsteadily. Windows, dishes, glassware broken; books fall off shelves; some heavy furniture moved or overturned; a few instances of fallen plaster. Damage slight to moderate to poorly designed buildings, all others receive none to slight damage.
VII. Very Strong Difficult to stand. Furniture broken. Damage light in building of good design and construction; slight to moderate in ordinarily built structures; considerable damage in poorly built or badly designed structures; some chimneys broken or heavily damaged. Noticed by people driving automobiles.
VIII. Destructive Damage slight in structures of good design, considerable in normal buildings with a possible partial collapse. Damage great in poorly built structures. Brick buildings easily receive moderate to extremely heavy damage. Possible fall of chimneys, factory stacks, columns, monuments, walls, etc. Heavy furniture moved.
IX. Violent General panic. Damage slight to moderate (possibly heavy) in well-designed structures. Well-designed structures thrown out of plumb. Damage moderate to great in substantial buildings, with a possible partial collapse. Some buildings may be shifted off foundations. Walls can fall down or collapse.
X. Intense Many well-built structures destroyed, collapsed, or moderately to severely damaged. Most other structures destroyed, possibly shifted off foundation. Large landslides.
XI. Extreme Few, if any structures remain standing. Numerous landslides, cracks and deformation of the ground.
XII. Catastrophic Total destruction – everything is destroyed. Lines of sight and level distorted. Objects thrown into the air. The ground moves in waves or ripples. Large amounts of rock move position. Landscape altered, or leveled by several meters. Even the routes of rivers can be changed.
What are the benefits of volcanic areas
Tourism: people want to come and visit
Agriculture: makes soil more fertile, 2-3x better crop yields
Minerals: mining for minerals
Energy: Can create geothermic energy to create heat and waters
How do you cope with tectonic hazards: protection and response to natural disasters
Inject liquid into faults Anchor heavy furniture to the floors Reinforce foundations of infrastructure Install automatic shutters Flexible gas and electricity cables Identification Number
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