1. Earthquake s and Volcanoes

2. Earthquakes Earthquake – is the shaking and trembling that results from the sudden movement of part of the Earth’s crust. Tsunamis – A giant sea wave produced by an earthquake.

4. Seismic Waves Focus – The point beneath the Earth’s surface where the rocks break and move, the underground origin of the earthquake. Epicenter – The point directly above the focus, on the earth’s surface where the origin of an earthquake is above ground.

5. Faults- Once the elastic limit of rocks is passed, they break and move along surfaces. 3 types of faults are: Normal Fault- These form at divergent boundaries. Reverse Fault- These form at convergent boundaries. Strike-Slip Fault- These form at transform boundaries.

7. Seismic waves – earthquake waves. *Three types. 1. Primary waves (P-waves) – arrive at a given point before any other type of seismic wave. Will pass through solid, liquid and gas.(fastest of the three) 2. Secondary Waves (S-waves) – arrive at a given point after the P wave. (second fastest) Will only travel thru solids. Will NOT pass through liquids and gases thus creating a shadow zone.

9. 3. Surface waves (L-waves) – slowest moving seismic waves. Arrives last.

12. Volcanoes Volcano – the place in the Earth’s surface through which magma and other materials reach the surface. Magma – rock that exists as a hot liquid deep within the earth. Lava – is magma that reaches the Earth’s surface.

14. Vent – an opening from which lava erupts. Crater – Steep walled depression around a volcano’s vent. Hot Spot – Hot rock that is a result of unusually hot areas in the mantle and core where volcanoes form on the Earth’s surface. Hawaii is the result of a hot spot.

15. Lava flows Basaltic – Is lava that contains a lot of water and rich in iron and magnesium. Thin and quiet eruptions. Granitic - this lava contains very little water and is rich in silicon and aluminum. Thick heavy lava causing gases to trap underneath producing large violent eruptions.

16. Composite Volcanoes – are made of alternating layers of rock particles and lava. Violent eruptions followed by quiet lava flows are the reasoning for the alternating layers.

17. Caldera – A roughly circular, steep-sided pit at the top of a volcanic cone whose diameter is at least three times its depth.

18. Andesitic - is a combination of both granitic and basaltic lava flows (quieter than granitic but more violent than basaltic). Gas filled lava – This lava cools to form hole filled rock that has the appearance of a sponge or loaf of bread. This rock type is typically light in weight. Pumice and scoria are examples of this type of igneous rock.

19. Liquefaction – Shaking up of wet soil making it unstable. This causes surface object to sink. Earthquake preparedness – Tie down heavy objects, take objects off of high shelves. Build on an earthquake proof foundation. Have a plan and emergency items.

20. Seismograph – is an instrument that detects and measures seismic waves. Seismogram – is the record of waves. (paper record) Seismologists – scientists who study earthquakes. Richter scale – calculation of the strength or magnitude of an earthquake. For every 1 point rise 30 times the energy is released. Magnitude - Height of a line traced on a seismogram.

21. Tephra – bits of rock or solidified lava dropped from the air. Volcanic Dust – Is fragments of rock that are blown into the air during a volcanic eruption. (very small particles) Volcanic Ash – Is particles blown into the air from a volcano that are bigger than volcanic dust yet smaller than anything else.

22. Volcanic Bombs – Are large rock particles that are blown out during a volcanic eruption. Volcanic cinders – are smaller volcanic bombs.

23. Cinder cone volcano – Volcanoes made mostly of cinders and other rock particles that have been blown into the air. Narrow bases with steep sides due to loosely arranged cinder type eruptions.

25. Shield volcano – Volcanoes composed of quiet lava flows. Gently sloping sides with very wide base.

26. Dike – Batholith – Sill -

28. Dormant – (sleeping) has erupted but not in modern time. Extinct – Not known to have erupted in recorded time. Usually weathered down to base. Active – well, it is active in modern time. ZONES Ring of fire – is the zone of active earthquakes and volcanoes due to very active tectonic plate movement.

30. Mid-Atlantic ridge – chain of ridges caused by sea floor spreading.