2/13/15 Bell Ringer (L32)

How are mid-ocean trenches formed?

Turn in your projects!

• Volcano Brochure • Plate Tectonics Posters

• Are due today! Turn in bin!

Video:

https://www.youtube.com/watch?v=JrBaiPN6AW8

R35: Anatomy of an Earthquake

Earthquake: sudden motion or trembling of Earth caused by the quick release of energy in rocks

-Occurs on FAULT lines -Pressure and stress build up in rocks and are released (resulting in the earthquake)

-Rock can move from a few centimeters up to 2 meters during an earthquake

R35: Anatomy of an Earthquake

R35: Anatomy of an Earthquake

R35: Anatomy of an Earthquake

Wave: moves energy from one place to another

Waves that travel through rocks are seismic waves.

R35: Anatomy of an Earthquake

Quick write: Where does an earthquake start at?

2-3 COMPLETE sentences

R35: Anatomy of an Earthquake

Focus point: the point where the rocks start to fracture

The focus point is the origin (start) of the earthquake

L36: Anatomy of an Earthquake

Epicenter: the point on the Earth’ s surface directly above the focus point

*Earthquake waves start at the focus and travel outward in all directions

*Earthquake waves do not originate at the epicenter

L36: Anatomy of an Earthquake

R36: Measuring Earthquakes

P Waves: (primary waves) -fastest kind of seismic wave-first to arrive at a seismic station -Moves through solids and liquids (water or layers of earth)

R36: Measuring Earthquakes

S waves: (Secondary waves)-travel slower than P waves-second to arrive at seismic station-can ONLY travel through solids

R36: Measuring Earthquakes

R36 Measuring Earthquakes

R36 Measuring Earthquakes

https://www.youtube.com/watch?v=gl4FvHKzAlU

R36 Measuring Earthquakes

How do we measure earthquakes?

Seismograph: machine that records seismic waves (p and s waves)

L37: Earthquake Scale

Geologists have created scales for measuring the strength of earthquakes.

Mercalli Scale: measures intensity of earthquakes based on how destructive it is on buildings and people (I- XII)I- Not felt XII-Extreme

L37: Earthquake Scales

• Richter scale: measures the magnitude of the earthquake based on how much energy it releases (1-10)

• 1- Not felt• 10- Extreme

R37: Earthquake Research Project

Research and earthquake (one you haven’t heard of before) Write a 1 page paper in your notebook Include:-Name of Earthquake -When and where it happened -What did it measure at? (richter/mercalli)-What was damaged? (explain)-Death toll? -Other interesting facts