Exam 1 Flashcards
Any natural hazaard that could potentially cause damage
Hazaardous Event
a natural emergency that affects people and whose response needs exceed the available resources of the affected community.
Natural Disaster
The product of extent, effects, probability, and importance of the outcome; if any of these factors is zero, there is zero chance
Risk
Activities to reduce losses from future disasters, including prevention and protection; something done before a disaster strikes to reduce/lessen damager/severity
Mitigation
Alter- modifying the hazard to eliminate or reduce the frequency of its occurrence; ex: triggering an avalanche under controlled conditions
Avert-redirecting the impact away from a vulnerable location by using structural devices or land treatment to shield people and development from harm; ex: levees, dike, dams
Adapt- Modifying structures and altering design standards of construction; ex: seismic safe construction
Avoid-keep people away from the hazard area or limiting development and population in a risk area; ex: not building in a landslide zone
4 A’s of Mitigation
Outermost layer of earth, what you walk on every day, only layer you’ve ever seen.
Crust
Outer layer of earth that is rigid and solid; made up of crust and part of the mantle; tectonic plates are made of
continental
oceanic
Lithosphere
low density because it is made of relatively light-weight minerals; light & buoyant
Continental lithosphere
dense & heavy lithosphere because it is compose of heavier minerals
Oceanic Lithosphere
Introduced the theory that the continents use to be together (Pangea) and began to drift apart about 200 million years before
Alfred Wegener
-the remarkable fit of the South American and
African continents
-occurrences of unusual geologic structures and of plant and animal fossils found on the matching coastlines of South America and Africa, which are now widely separated by the Atlantic Ocean.
Evidence of continental drift
Harry Hess & Robert Dietz theorized that mid-ocean ridges mark structurally weak zones where the ocean floor was being ripped in two lengthwise along the ridge crest. New magma from deep within the Earth rises easily through these weak zones andeventually erupts along the crest of the ridges to create new oceanic crust.; mid-ocean ridge; pushing the continents apart
Seafloor spreading
long mtn chains and valleys that run along the ocean floor; on a divergant plate boundary; magma comes up and keeps pushing the plates apart
Mid-ocean ridge
Earth’s lithosphere is broken up into pieces and those pieces move relevant to each other.
Theory of Plate Tectonics
plates move apart or separate; ex: mid-ocean ridge; new crust is created
Divergent plate boudnary
Two plates come together (collide); depending on which two types are coming together depends on what will happen (i.e. subduction zone, continent vs continent)
Convergent plate boundaries
One plate goes under (subducts) another one; ocean vs continental, or ocean vs ocean; ex: chile, Peru Columbia, Boliva(Andes Mountains), Alaska, Indonesia (All part of the Ring of Fire); caribbean and Italy
Subduction Zone
No subduction; plates push each other up like the Himalayas (Central Asi, India, China, Nepal, Pakistan, Afghanistan)
Continental vs Continental Convergent Plate Boundary
Most happen at plate boundaries
Volcanoes & Earthquakes
place in the middle of a plate where there are volcanoes that are NOT related to subduction; idea of mantle plumes (like a lava lamp); (ex:yellowstone, hawaii)
Hotspots
Point underground where the crust ruptures, origin point of an earthquake
Hypocenter (or focus)
Point on the surface directly above the hypocenter
Epicenter
Intensity scale uses Roman numbers I-Xii that measures damage; I=no damage; XII=absolutely destroyed;
Mercalli Scale
Scientific measurement of an earthquake; Richter or Moment Magnitude
Magnitude
measures the amount of energy released based on the amplitude of the largest wave
Richter Scale
Amount of energy release based on amplitude, length of the fault rupture, surface rupture, etc; believed to give a more accurate number
Moment Magnitude Measure
When the ground loses it’s strength & cohesion and no longer behaves like a solid
Liquefaction
is a set of ocean waves caused by any large, abrupt disturbance of the sea, typically an upward or downward displacement of the seafloor, or a landslide; can be caused by earthquakes or volcanoes
Tsunami
past-most started from oil lamps, wood stoves, and chimney(USGS); liquefaction had severed the underground water pipes.
modern-caused fires involves installation of gas-powered appliances and their supporting piping
Fires
release of energy into the ground that causes seismic waves, higher energy and higher amplitudes (= harder shaking).
shaking hazaard
- Seismic engineering-allows the building to move with the motion
- strapping furniture, water heaters, furnaces
- use of lighter building materials (no heavy roof tile, bricks)
Earthquake mitigation
Waves generated at the hypocenter; are compressional waves, like sound waves, arrive first “primary”
p-waves
wave generated at the hypocenter; shear waves; about a third slower than primary waves; are second to arrive at a seismometer; “secondary”
S-waves
Only happen at the surface and include Rayleigh and Love waves; travel slower than s-waves, and have higher amplitudes, especially in soft soils; do most of the damage in earthquakes, and are the memorable ones most people describe after a quake.
Surface Waves
Crust is getting spread apart; block moves down leaving a fault scarp
Normal faults
crust is getting squished together; block moves up
Reverse Fault
a reverse fault but it is flat or shallow
Thrust fault
crust moves horizontally; two blocks are sliding past each other; ex San Andreas Fault
Strike-Slip Fault
- Only case study where all hazards caused significant damage: Fire, Earthquake, Tsunami
- Historians believe it changed European history
- Jesuits opposed reconstruction-saw it as a punishment from God
- Happened on All Saints Day, Nov 1, 1755
- 9:30 AM
- Magnitude 8.5 to 9.0
- Death toll 30,000 to 60,000
Lisbon, Portugal Earthquake 1755
- A series of earthquakes
- biggest earthquakes that far east in the US (3 quakes between 7.5, 7.3, 7.5)
- the mississippi river flowed backwards
- unknown death toll, but small, sparsley populated
- New Madrid fault zone (ancient plate boundary (the failed Reelfoot rift)
- church attendance skyrocketed, end of world
New Madrid, Missouri 1811-1812
- Deadliest EQ in US history; fire destroyed much
- Death toll 3000, 225,000 homeless (more than half the city)
- Bank of America started
- Elastic rebound theory
- MW 7.9
- transform boundary (San Andreas strike-slip fault)
- $400 million in 1906 (11 billion today)
San Francisco, 1906
*One of the largest recorded EQ (Alaska is another); mw 9.5
*caused a big tsunami; waves up to 25 meters
*Because of it Chile became more earthquake prepared nation
*2000 dead
$550 million us dollars
*Naca plate subducts under S American plate; convergent
Chile, Valdivia, 1960
*Most deaths for EQ in modern time (M7.8)
*240,000 deaths, more recently estimated at 655,000
*nearly every building in the city collapsed; liquefaction was common
*Asia-Pacific convergent (some say N America-Pacific plates)
*
Tangshan, China 1976
- Big deal because of the land build up and Liquefaction
- caught people off guard
- M6.9
- 5500 deaths (some say 6300)
- Phillippine plate subducts under Japan (Eurasian/N American Plate; convergent
- over $100 billion dollars
- raised construction standards after
Kobe, Japan 1995
- Haiti-huge humanitarian disaster, (7.0);, w. hemisphere’s poorest country
- Haiti-low construction standards
- Chile-Stronger earthquake (8.8) but way less damage
- prosperous, well prepared and modern construction.
- Vividly demonstrates the importance of construction standards
Haiti and Chile, 2010
- 9.0 earthquake that caused a tsunami, landslides
- damage at the Fukushima nuclear power plant
- death toll 15,895
- Convergent boundary, Pacific plate subduct under Japan
- over $300 billion; costliest natural disaster of all time
- increased trade deficits and national debt
Japan “Tojuku”, 2011
