Today… Get out… My learning progress - The Earthquake Story In class… Review for test At Home Study!

Answers we now know… How does Earthquake energy move? How are earthquakes measured? How are earthquakes located? How can we make earthquake proof buildings? What happens at plate boundaries? What affects the strength of an earthquake? How do we know what it is like inside the earth? How and why do the plates move?

Earthquake Story Earthquakes energy travels in seismic waves: P, S and Surface Waves Earthquakes are measured and recorded by seismometers Earthquake epicenters are located by finding the intersecting distances from 3 seismometers Earthquake locations show that the Earth’s crust is broken into plates Earthquakes are different sizes because faults have different amounts of friction We know the Earth has four layers: crust, mantle, inner and outer core because of the way waves move through Plates move in 4 ways: converging, diverging, transforming, and subducting Earthquake resistant buildings need to be well supported and anchored to bedrock The plates move because heat from the core causes convection in the mantel which drags the plates

Review 1 Where and why do most Earthquakes occur? – Earthquakes occur when the tension built up along plate boundaries and faults from friction releases. The energy released shakes the ground and that is what we call an earthquake.

Review 2 Name the three energy waves, tell how they move, their relative speed and where they originate. – P-waves: Push and pull wave the comes from the focus. It is the fastest – S-waves: Side to side motion that comes from the focus. These are second fastest. – Surface waves: A rolling motion that travels along the surface. These are the slowest.

Review 3 What machine creates this kind of record? Which city was closest to the epicenter? How do you know? How would you use this data to find the epicenter of the earthquake? Juneau Richmond Honolulu This is made by a seismometer. Juneau is the closest city. You can tell because the earthquake waves arrived there first. The difference in the S and P arrival times will tell how far away it is. Then, if circles are drawn with the radius of each distance from each city, where the three intersect is the epicenter.

Review 4 What is a plate? – A plate is a piece of the Earths crust. The entire crust is broken into pieces called plates. Name the types of plate boundaries and give a real example of each. (The more local the better) – Diverging The Atlantic mid-ocean ridge – Transform Example: San Andreas Fault in California – Subducting Under Washington making the Cascades – Converging example: the Himalaya Mountains

Review 5 Describe what the layers of the Earth are like in terms of temperature and state (solid liquid or gas) – Crust less than 1%, is solid, brittle and cool – The mantle is about 44% of the Earth’s radius, hot and taffy like – The outer core is about 33% of Earth’s diameter, liquid metal and very hot – The inner core is solid metal, extremely hot and 22% of Earths radius Explain how they know. – The know because during earthquakes, P and S waves travel through the interior of the Earth and the way they travel can show an image of the interior. For example S - waves do not travel through liquid

Review 6 We know that Earthquakes happen along plate boundaries, but what other events can happen near a plate boundary? Give three. – Volcanoes – Near subducting boundaries – Tsunamis – When there is an earthquake in the ocean – Mountain building – Converging plates – New ocean floor – diverging boundaries

Review 7 What is the current theory of why the plates move? – The plates move because there are convection currents in the mantle that drag the plates with them as they move. Where does heat for convection come from? – The energy for the convection current comes from the core.

You will do great! Use Knowledge Map # 60 – 74 I can’s All Earthquake “I can’s…” The test is … 10 multiple choice 10 Written – short answer 2 or 3 fill in the blank type

Today… Get out… Pencil Something to do after the test In class… Test At Home Nothing When finished place test in turn in drawer