The document provides information about earthquakes, including what causes them, how they are measured, different types of seismic waves, damage from earthquakes, and safety tips. Specifically, it explains that earthquakes are caused by the sudden release of energy at fault lines in the earth's crust. They can be measured using seismographs which record the amplitude and duration of seismic waves. Safety advice includes having an emergency plan and supplies like food, water, and first aid ready both during and after an earthquake.

1. RECAP

2. What is the theory that explains and unifies different geologic phenomena? Recap

3. What is the theory that states that continents were once joined and then they broke apart? Recap

4. Give 3 evidences of Continental Drift provided by Wegener. Recap

5. What do you call the remanent magnetism from ancient rocks recording the direction and strength of the Earth’s magnetic field at that time? Recap

6. What is the theory that states that the seafloor separates at oceanic ridges? Recap

7. What are Earthquakes? The shaking or trembling caused by the sudden release of energy (also known as a quake, tremor or temblor) Usually associated with faulting or breaking of rocks Continuing adjustment of position results in aftershocks

11. Where Do Earthquakes Occur and How Often? ~80% of all earthquakes occur in the circum-Pacific belt most of these result from convergent margin activity ~15% occur in the Mediterranean-Asiatic belt remaining 5% occur in the interiors of plates and on spreading ridge centers more than 150,000 quakes strong enough to be felt are recorded each year

13. Causes of Earthquakes Passing the Elastic Limit Causes Faulting Applied stresses can cause rocks to bend and stretch Eventually rocks will break away from one another Area in which the rocks break and move is called a fault Vibrations produced is called an earthquake Earth’s crust movement causes the stresses applied

14. What is the Elastic Rebound Theory ? Explains how energy is stored in rocks Rocks bend until the strength of the rock is exceeded Rupture occurs and the rocks quickly rebound to an undeformed shape Energy is released in waves that radiate outward from the fault

16. The Focus and Epicenter of an Earthquake The point within Earth where faulting begins is the focus, or hypocenter The point directly above the focus on the surface is the epicenter

17. Measuring Earthquakes Seismology Seismologists - People who study earthquakes and seismic waves Use instruments called seismographs Record seismic waves A drum with a sheet of paper vibrates and a stationary pen marks the vibrations on the paper The height of the lines are used to measure the energy released from the earthquake called the magnitude

18. Seismographs record earthquake events

19. What are Seismic Waves? Response of material to the arrival of energy fronts released by rupture Two types: Body waves P and S Surface waves R and L

20. Body Waves: P and S waves Body waves P or primary waves fastest waves travel through solids, liquids, or gases compressional wave, material movement is in the same direction as wave movement S or secondary waves slower than P waves travel through solids only shear waves - move material perpendicular to wave movement

21. Surface Waves: R and L waves Surface Waves Travel just below or along the ground’s surface Slower than body waves; rolling and side-to-side movement Especially damaging to buildings

22. The Economics and Societal Impacts of EQs Damage in Oakland , CA, 1989 Building collapse Fire Tsunami Ground failure

23. How are the Size and Strength of an Earthquake Measured? Intensity subjective measure of the kind of damage done and people’s reactions to it isoseismal lines identify areas of equal intensity

24. How are the Size and Strength of an Earthquake Measured? Magnitude Richter scale measures total amount of energy released by an earthquake; independent of intensity

26. What are the Destructive Effects of Earthquakes? Ground Shaking amplitude, duration, and damage increases in poorly consolidated rocks

27. Tsunamis Caused by the movement of the ocean floor Causes a disruption in the water Some are so wide that a large ship can travel over the wave without knowing Recent earthquake in the Indian Ocean created a tsunamis that was 100 feet high and moving at 500 mph

28. Can Earthquakes be Predicted? Earthquake Precursors changes in elevation or tilting of land surface, fluctuations in groundwater levels, magnetic field, electrical resistance of the ground seismic dilatancy model seismic gaps

29. Can Earthquakes be Predicted? Earthquake Prediction Programs include laboratory and field studies of rocks before, during, and after earthquakes monitor activity along major faults produce risk assessments

30. Can Earthquakes be Controlled? Graph showing the relationship between the amount of waste injected into wells per month and the average number of Denver earthquakes per month Some have suggested that pumping fluids into seismic gaps will cause small earthquakes while preventing large ones

31. EARTHQUAKE SAFETY

32. Family Readiness Create a family Earthquake plan Know the safe spot in each room Know the danger spots Decide where your family will reunite if separated Keep a list of emergency phone numbers Develop a survival kit for work, car, and home

33. Home Preparedness Learn how to shut off gas, water, and electricity Check chimneys, roofs, and wall foundations for stability Secure heavy furnishings Secure water heater and appliances Keep heavy objects on lower shelves Maintain emergency food, water, medicine, first aid kit, tools, and clothing

34. Emergency Supplies First Aid supplies Band-Aids antibiotic ointment latex gloves cold/hot packs ace bandages arm sling Tylenol or Advil diarrhea medication Equipment work gloves shovel tents sleeping bags ready to eat foods clothing radio, flashlights CASH

35. Emergency Food Camp or backpacking stove propane tank Canned foods manual can opener Granola bars Energy bars

36. Safe Drinking Water Store a supply of water 1 and 5 gallon containers do not store on concrete Purifying tap water 8 drops bleach per gal of water add bleach when storing or, boil for 10 minutes Water from water heater turn off gas or electric turn off cold water supply once cooled, drain at bottom Other sources toilet storage tank melted ice cubes water trapped in pipes

37. During an Earthquake Stay away from windows, bookcases, file cabinets, heavy mirrors, and other heavy objects that could fall Duck under a desk or sturdy table Watch for falling plaster or ceiling tiles Stay undercover until the shaking stops, and hold onto your cover If the desk or table you are under moves… move with it If in your car, stop, but not on a bridge, or under trees or a power line If outside, stay outside, and move to an area clear of overhead trees, power lines, or objects that could fall from a structure Don’t forget about aftershocks

38. After The Earthquake Be prepared for aftershocks, plan for cover when they occur Check for injuries, give first aid as necessary Remain calm, try to reassure others Wear shoes to avoid injury from broken glass Check for fire and take appropriate actions Check gas, water, and electric lines Tune to emergency broadcast system on radio