A type of threat that hasn't happened yet, but there's potential for some serious damage
What is a natural disaster?
-Causes significant property damage
-A natural event that has a negative effect on humans
What is a great natural disaster?
-Effects many people
-Covers a large area
-Has a long recovery
-Requires external assistance
What is risk?
What is mitigation?
Activities to reduce losses from future disasters, including prevention and protection
What are the methods of mitigation?
Alter-modify the hazard
Avert-redirect the hazard
Who is Alfred Wegener?
He proposed the idea of continental drift and the supercontinent called Pangaea
Who is Harry Hess and Robert Dietz?
They proposed mantle convection, seafloor speaking, and lithospheric plates
What are some of the evidences that Alfred Wegener used and how do they support plate movement?
-The fit of the continents
-Matching geology (location of glaciers, fossils, and rock types)
What are some of the modern evidences for plate tectonics and how do they support plate movement?
-Mid ocean ridges
What are the layers of the Earth?
-Inner (solid) and outer core (liquid)
-Mantle (mesosphere has stiff rocks, asthenosphere is soft plastic, lithosphere is hard like rock)
What are the types of plate boundaries?
Convergent, divergent, transform
What features do you find at each type of plate boundary? Why?
-Convergent (trenches) plates create volcanoes and earthquakes. Divergent plates are mostly volcanoes. (mid ocean ridges) Transform plates earthquakes
-Convergent: earthquakes are deep and huge, volcanoes are big and dangerous. Means coming together
-Divergent: earthquakes are weak and shallow, volcanic activity is mild. Means going away
-Transform: earthquakes are shallow and intermediate strength, no volcanoes. Means sliding across
What happens in subduction zones? AKA convergent plates
-Largest earthquakes, tsunamis, volcanoes
What is a hypocenter/focus?
Point where initial rupture occurs beneath the surface of the fault
What is an epicenter?
Point on earth's surface directly above focus, usually not on the fault
What is a scarp?
Where the fault plane broke the earth's surface, exposed area
What are the different fault types?
-Normal fault: hanging wall moves down(divergent)
-Reverse/thrust fault: hanging wall moves up (convergent)