Earthquake

Earthquakes are the shaking, rolling or sudden shock of the earth’s surface. They are the Earth's natural means of releasing stress. Earthquakes can be felt over large areas.
Earthquakes cannot be predicted, although scientists are working on it.

1. TOPIC OF PRESENTATION EARTHQUAKE

2. TABLE OF CONTENTS DEFINATION OF EARTHQUAKE PLATE TECTONICS CAUSES OF EARTHQUAKE TYPES OF EARTHQUAKE EARTHQUAKE WAVES FAULTS SEISMOGRAPH TUSUNAMI IMPORTANT TERMINOLOGY RICHTER SCALE EARTHQUAKE SAFTEY TIPS RECENT STUDIES

3. Earthquakes are the shaking, rolling or sudden shock of the earth’s surface. They are the Earth's natural means of releasing stress. Earthquakes can be felt over large areas. Earthquakes cannot be predicted, although scientists are working on it.

4. The definition of an earthquake is… vibrations that cause the breaking of rocks . These vibrations move in all directions through the earth. They begin at a point along a fault . Earthquake?

5. There are about 20 plates along the surface of the earth that move continuously and slowly past each other. When the plates squeeze or stretch, huge rocks form at their edges and the rocks shift with great force, causing an earthquake.

6. The plate tectonic theory is supported by a wide range of evidence that considers the earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another.

7. As the plates move they put forces on themselves and each other. When the force is large enough, the crust is forced to break. When the break occurs, the stress is released as energy, which moves through the Earth in the form of waves, which we feel and call an earthquake.

8. The plates are all moving in different directions and at different speeds. Sometimes the plates crash together, pull apart or sideswipe each other. When this happens, it commonly results in earthquakes.

9. San Andreas Fault Line The San Andreas Fault is the sliding boundary between the Pacific Plate and the North American Plate. It slices California in two from Cape Mendocino to the Mexican border. San Diego, Los Angeles and Big Sur are on the Pacific Plate. San Francisco, Sacramento and the Sierra Nevada are on the North American Plate http://geology.com/articles/images/san-andreas-fault-map.jpg

10. There are four major types of Earthquake Types of earthquake

11. A tectonic  earthquake  is one that occurs when the earth's crust breaks due to geological forces on rocks and adjoining plates ► A  volcano tectonic earthquake  is an earthquake induced by the movement (injection or withdrawal) of magma. The movement results in pressure changes in the rock around where the magma has experienced stress

12. An Explosion Earthquake is an earthquake which results of nuclear and chemical devices. This occurs when enormous energy nuclear energy is released during underground nuclear explosions ► Collapse Earthquakes are small earthquakes in the underground and in mines that are caused by seismic waves produced from the explosion of rock on the surface. 

13. THERE ARE TWO MAJOR WAVES GENERATED WHEN EARTHQUAKE ACCURES

14. P-WAVES PRIMARY WAVE ARE FASTEST WAVE GENERATED FROM FOCUS AND REACH FIRST AT RECORDING STATION ITS TRAVEL ALONG THE DIRECTION OF WAVE PROPGATION AND SHAKE THE MATERIAL BACK AND FOUR DIRECTION S- WAVES S WAVES ARE WAVES GENERATED AFTER THE P WAVE OR PRIMARY WAVES AND SAID TO BE SECONDERY WAVES AND REACH RECORDING STATION AFTER THE P-WAVE

15. A.E.H LOVE DISCOVERD IT AND IT CAUSE HORIZONTAL GROUND MOTION PERPENDICULLER TO THE DIRECTION OF WAVE PROPOGATION IT REACH TO RECORDING STATION AFTER RAYLEIGH WAVE FREQUANCY OF THESE WAVE INCREASE WITH TIME THESE ARE HEIGHLY DUSTRUCTIVE WAVES

16. Rayleigh waves  are a type of surface acoustic wave  that travel on solids. They can be produced in materials in many ways, such as by a localized impact or by piezo -electric transduction, and are frequently used in non-destructive testing for detecting defects.

17. A fault is an area of stress in the earth where broken rocks slide past each other, causing a crack in the Earth's surface. There are 3 major types of faults which are as follows: Strike Slip Fault Normal Fault Thrust Fault

18. Normal Fault Normal fault Earth’s brittle crust becomes fractured along fault lines. Quakes occur along a normal fault when the two sides move apart. Rock slabs sitting above the fault slide down in the direction the plates are moving, like at the Mid-Atlantic Ridge.

19. Strike-Slip Fault Strike-slip fault Blocks can be sheared apart along strike-slip faults. They’re straight cracks in the crust where two plates are sliding horizontally past each other. Every time a section of the fault moves, an earthquake occurs.

20. Thrust Fault Thrust fault The 2011 Tohoku quake in Japan ruptured a thrust fault in a subduction zone. These zones are associated with Earth’s most violent quakes as oceanic crust grinds beneath continental crust, creating great friction. Huge stresses can build here and release the same energy as a thousand hydrogen bombs!

21. A seismograph is an instrument used for recording the intensity and duration of an earthquake.

22. A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage.

23. Tidal waves vs. Tsunamis tidal waves tsunamis

24. Important Terminologies: FOCUS - The point inside the earth surface from where the earthquake generated is called focus. EPICENTER - The point on the earth's surface directly above the source of the earthquake. ► Focal Depth In seismology, the depth of focus or focal depth refers to the depth at which an earthquake occurs.

25. Aftershock Secondary tremors that may follow the largest shock of an earthquake sequence. Such tremors can extend over a period of weeks, months, or years Deep Earthquake An earthquake whose focus is located more than 300 kilometers from the earth's surface. Earthquake-report.com differs from the official notification calling earthquakes with a depth of more than 100 km as "Deep". This is mainly because of the non-damaging impact of these earthquakes.

26. Richter Scale Developed in 1935 by Charles Richter in partnership with Beno Gutenberg, both of the California Institute of Technology, the scale was intended to be used only in a particular study area in California, and on seismograms recorded on a particular instrument, the Wood-Anderson torsion seismometer The Richter magnitude scale, assigns a single number to quantify the amount of seismic energy released by an earthquake. It is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a Wood–Anderson torsion seismometer output. So, for example, an earthquake that measures 5.0 on the Richter scale has a shaking amplitude 10 times larger than one that measures 4.0. The effective limit of measurement for local magnitude is about M L = 6.8. Charles Richter

27. RICHTER SCALE - A measurement of an earthquake's intensity. - Each one-point increase on the scale indicates ten times the amount of shaking and 33 times the amount of energy. - The energy released by a large earthquake may be equal to 10,000 times the energy of the first atomic bomb.

28. Richter Scale 1 - Minor Earthquake 2 - Moderate Earthquake 3 - Strong Earthquake 4 - Major Earthquake 5 - Great Earthquake

29. Earthquake Safety Tips BEFORE AN EARTHQUAKE: Choose a safe place in every room such as under a sturdy piece of furniture like a table or a desk where nothing can fall on you. Practice DROP, COVER AND HOLD ON! - Drop under something sturdy, hold on, and protect your eyes by pressing your face against your arm. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water.

30. DURING AN EARTHQUAKE: DROP, COVER AND HOLD ON! Stay indoors until the shaking stops. Stay away from windows. If you’re in bed, hold on and stay there, protecting your head with a pillow. If you’re outdoors, find a clear spot away from buildings, trees and power lines. Then, drop to the ground. If you’re in a car, slow down and drive to a safe place. Stay in the car until the shaking stops.

31. AFTER THE SHAKING STOPS: Check for injuries. Inspect your home for damage. Eliminate fire hazards, so turn off the gas if you think its leaking. Expect aftershocks. Each time you feel one, DROP, COVER AND HOLD ON.

32. Recent studies: In recent studies, geologists claim that  global warming  is one of the reasons for increased seismic activity. According to these studies melting glaciers and rising sea levels disturb the balance of pressure on Earth's tectonic plates. T hus causing increase in the frequency and intensity of earthquakes.

33. 10 Destructive Earthquakes Location Date Magnitude Chile May 22, 1960 9.5 Prince William Sound, Alaska March 28, 1964 9.2 Andréa of Islands, Aleutian Islands March 9, 1957 9.1 Kamchatka Nov. 4, 1952 9.0 Off western coast of Sumatra, Indonesia Dec. 26, 2004 9.0 Off the coast of Ecuador Jan. 31, 1906 8.8 Rat Islands, Aleutian Islands Feb. 4, 1965 8.7 Northern Sumatra, Indonesia March 28, 2005 8.7 India-China border Aug. 15, 1950 8.6 Kamchatka Feb. 3, 1923 8.5

34. Thank you for listening! Don’t forget to drop, cover and hold-on! ☺