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