GEOG211
-Earthquakes don’t normally kill but buildings do
A- What are earthquakes and what causes them to take place? a- Earthquake: An earthquake is a trembling or shaking movement of the Earth’s surface b- Seismic Waves (Underground waves) cause earthquakes c- Seismic Waves move through the earth d- Waves are created by movement i. Movement of Magma into the crust in volcanoes create seismic waves ii. Huge man-made explosions cause movement as well iii. Water behind Dams move and create Seismic waves iv. Tectonics plates are under tension and sometimes they move suddenly v. A sudden release of energy by the movement of plates create Seismic Waves e- Focus-The point where the movement occurs (underground) f- Epicenter- The point above the focus on the earth’s surface is called the epicenter i. Waves are the strongest nearest the epicenter
B- Tsunamis a- Tsunamis- Wave train or series of waves , generated in a body of water by an impulsive disturbance that vertically displaces the water column b- Travel at hundreds of miles per hour c- Waves sometimes get as high as 100 feet and cause great damage to the coast
2/14/13
Limestone covers 10% of the Earth’s surface
Chemical Weathering – chemical alterations
Pure Water = harmless as an agent of chemical weathering
Pure Water + dissolved carbon dioxide = carbonic acid
Granite contains Quartz, mica and potassium feldspar(minerals)
Potassium feldspar goes through some chemical alteration when exposed to carbonic acid. A- Plants as agents of chemical weathering a- Some plants extract minerals from rocks which leads to disintegration of the rock structure B- Features produced by solution a- Carbonic acid dissolves limestone b- Carvers are formed c- Travertine deposited carbonic matter d- Sinkholes- Formed when a underground cavern collapses C- Karst Topography a- Marked by the regions of soluble rock such as limestone and dolomite b- There is normally the absence of surface drainage c-
Surface Water A- Overland Flow – Water that flows over land but not in streams, creeks, rivers etc. a- Sheet flow- continuous flow of water over smooth surfaces b- Rivulets – movement of water over tiny groves B- Stream – long narrow