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Earthquakes-Faults-Lesson.pptx
- 2. Objectives: Differentiate the: 1. Epicenter of an earthquake from its focus; 2. Intensity of an earthquake from its magnitude; 3. Active and inactive faults.
- 4. Pacific Ring of Fire The Pacific Ring of Fire is an arc around the Pacific Ocean where many volcanoes and earthquakes are formed.
- 6. ■ FAULT: fracture/break in the Earth’s crust where earthquakes are most likely to occur. Many faults occur along plate boundaries. Faults can also occur anywhere in the crust where rocks are bent (folded) until they break. Faults occur as a result of various types of stress.
- 7. Different Faults Move in Three Different Ways Stress - the force applied to rocks. Tensional - rocks are stretched away from each other. Compressional - rocks are pushed toward each other. Shear - rockes are pushed toward each other but not the same axis.
- 8. HANGING WALL vs FOOTWALL ■ A fault divides rock into two fault blocks ■ For any inclined fault, the block above the fault is the hanging wall block, and the block below the fault is the footwall block www.data.scec.org/Module/footnt02.html
- 9. Three Types of Faults 1.Dip Slip Fault 2.Strike Slip Fault 3.Oblique Slip Fault
- 10. CLASSIFICATION of DIP-SLIP FAULTS ■ NORMAL FAULTS: Dip-slip faults on which the hanging wall moves down relative to the footwall • Place younger rocks on older rocks • Form in regions of lateral extension www.data.scec.org/ Module/footnt02.html
- 11. EXAMPLES OF NORMAL FAULTS Conjugate Normal Faults, Canyonlands National Park darkwing.uoregon.edu/~millerm/conjN1.html Normal Fault Scarps, Turkey www.msnucleus.org/.../pt/hazards/4/pth4_1a.html Outcrop scale normal faults
- 12. CLASSIFICATION of DIP-SLIP FAULTS ■ THRUST or REVERSE FAULTS: Dip-slip faults on which the hanging wall moves up relative to the footwall • Place older rocks on younger rocks • Form in regions of lateral compression www.data.scec.org/ Module/footnt02.html
- 13. EXAMPLES OF THRUST FAULTS Thrust Fault in Concrete from 1964 Quake, Anchorage, Alaska www.ucmp.berkeley.edu/.../alaska/0709log.html Thrust Fault in Sediments www001.upp.so-net.ne.jp/fl-fg/05-01.htm Outcrop scale thrust faults www.pitt.edu/.../7Structures/ReverseFaults.html
- 14. CLASSIFICATION of STRIKE-SLIP FAULTS ■ RIGHT-LATERAL (DEXTRAL) FAULTS: Strike-slip faults across which the block moves to the right ■ LEFT-LATERAL (SINISTRAL) FAULTS: Strike-slip faults across which the block moves to the right
- 15. EXAMPLES OF STRIKE-SLIP FAULTS San Andreas Fault, CA http://education.usgs.gov/california/ pp1515/chapter2/fig2-21.jpg Right Lateral Slip, Izmit, Turkey, 1999 Quake http://www.geo.uib.no/jordskjelv/ Right Lateral Fault in Asphalt www.uwsp.edu/.../fault_transform_photo.html
- 16. OBLIQUE SLIP FAULTS A fault which has a component of dip-slip and a component of strike-slip is termed an oblique-slip fault.
- 17. Difference between focus and epicenter FOCUS – where the rock breaks and seismic waves begin; can be at deep or shallow depths. Epicenter – point on the surface directly above the focus, usually what is used to locate the position of an earthquake.
- 18. How Do Faults Produce Quakes? Energy from inside the earth make the ground move. There is no movement friction right away because of the friction. Friction held the rocks together, but once the FRICTION IS OVERCOME, the ground will move, and the earthquake will occur.
- 19. Difference between Intensity and Magnitude
- 21. Active vs Inactive Fault An active fault is that has moved in the past and is expected to move again. Meaning, it has generated earthquakes before and is capable of causing more in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years. Inactive faults are structures that we can identify, but which do no have earthquakes. As you can imagine, because of the complexity of earthquake activity, judging a fault to be inactive can be tricky, but often we can measure the last time substantial offset occurred across a fault. If a fault has been inactive for millions of years, it's certainly safe to call it inactive. However, some faults only have large earthquakes once in thousands of years, and we need to evaluate carefully their hazard potential.
- 22. Fault Lines in the Philippines Fault Lines Affected Areas 1. Marikina Valley Fault Marikina, Montalban, San Mateo, Pasig, Taguig, Muntinlupa, San Pedro, Biñan, Santa Rosa, Carmona, Tagaytay, Calamba, Oriental Mindoro 2. Western Philippine Fault Mindoro Strait, Luzon Sea, Sulu Sea, Panay Gulf 3. Central Philippine Fault The entire Ilocos Norte, Aurora, Quezon, Masbate, Eastern Leyte, Southern Leyte, Agusan del Norte, Agusan del Sur, Davao del Norte 4. Eastern Philippine Fault Philippine Sea 5. Southern Mindanao Fault Celebes Sea as well as the Moro Gulf
- 26. Role Playing Make a 2-3 minute role playing act showing what people do when an earthquake strikes.
- 27. HOw you will be scored Cocept is clear 5 Convincing and COnsistent 5 Prepared well and organized 5 Role Play is not boring 5 20
- 28. Generalization An earthquake is a sudden movement of the earth’s crust caused by the release of stress accumulated along geologic faults or by volcanic activity which can result to destruction of properties and loss of many lives.
- 29. For Tomorrow We will do an activity. Please bring the following. 1. Two sheets of cardboard 2. Fine Sand 3. Ruler 4. Newspaper
- 30. Objectives: ● Demonstrate how underwater earthquakes generate tsunamis. ● Explain how earthquake waves provide information about the interior of the Earth.
- 31. Quiz Time: 1. What does the word “tsunami” mean in Japanese? A. Tidal Wave C. Harbor Wave B. Century Wave D. Killer Wave 2. What is frequently a warning sign of an impending tsunami? A. Seawater suddenly retreats from the shore. B. Winds suddenly change direction C. The sky suddenly clears D. All of the above
- 32. Quiz Time: 3. What of the subsequent is true about tsunamis? A. It’s associated with tides B. It’s a large moving ridge C. It’s because of the upward movement of rock at the seafloor D. It’s because of the upward movement of rock ashore. 4. Which attributes to the vibrations created by an earthquake? A. Sea – surface waves C. Seismic Waves B. Pressure waves D. Tidal waves
- 33. Quiz Time: 5. Which of the following sequences correctly lists the different arrivals from first to last? A. P waves….. S waves…… Surface Waves B. Surface Waves….. P waves….. S waves C. P waves….. Surface waves….. S waves D. S waves….. P waves…..Surface waves
- 35. Tsunami (soo.naa.mee) ● Japanese Word: “tsu” – port of harbor “nami” – wave Series of wave in a water body caused by a displacement of a large volume of water generally in an ocean or large lakes.
- 36. What generate tsunami? ● Earthquakes ● Volcanic Eruption ● Underwater explosions above and below water Tsunami & Earthquake Philippines Tsunami and Earthquakes can happen anytime along the Pacific Ring of Fire
- 37. Tsunami in the Philippines ● The last measurable tsunami in the Philippines affected the Northern and Eastern seaboards on 11th March 2011.
- 38. Activity 1 ● After performing this activity, you should be able to: 1. explain how tsunamis are generated; and 2. infer why tsunamis do not always occur even when there is an earthquake. Materials Needed:: Flat basin or laundry tub (batya) Water Rectangular piece of plastic panel or plywood or card Rock
- 39. Procedure: 1. Put water in the container. Place the rock in the water at one end of the container. 2. At the other end of the container, put the plastic panel flat at the bottom of the container. 3. You will need some help: a person to watch the surface of the water, and another to watch the level of water by the rock. 4. Hold the corners of the plastic panel with your thumbs and fingertips. Wait for the water to stop moving. Using your fingertips, jerk the edge of the plastic board up.
- 40. Guide Questions: 1. What was formed in the water by the sudden push of the plastic panel? 2. How was the water level by the rock affected by the wave? 3. What does the water represent? How about the rock? 4. What does the plastic panel represent?
- 41. Fault ● Fault are found not only on land but also under the sea.
- 42. Wind waves vs Tsunami waves
- 43. How Earthquakes related to Tsunamis?
- 44. Inside the Earth How Earthquake waves provide information about the Interior of the Earth? Seismic Waves – the waves of energy caused by the sudden breaking of rock within the Earth or an explosion. They are the energy that travels through the Earth and is recorded on seismograph.
- 45. Seismic Waves Seismic Waves radiate from the focus of an Earthquake. It can travel in several ways. There are several types of seismic waves. 3 Basic Types of Seismic Waves: 1. P wave 2. S wave 3. Surface Wave
- 47. P wave & S wave
- 48. Surface Waves ● Similar to water waves ● Travel under the Earth’s surface ● They are typically generated when the source of the Earthquake is close to the Earth’ssurface. ● It travel slower that S waves but they can be much larger in amplitude and can be the most destructive of seismic waves.
- 49. What can Seismic Waves tell us?
- 52. Good from the Bad?
Editor's Notes
- Fractures between two blocks of rocks.
- Tensional Forces – Normal
- How do faults produce Earthquake?
- Origin of the earthquake located underground. The breaking of the rocks will start at the point where rocks are weakest. This spot where the first break occurs is called the focus or hypocenter. (under or beneath) After the breaking there is a vibration, and the vibration is usually first felt in the surface above the focus, which is the epicenter. (Epi-surface)
- Magnitude – Hindu Arabic – 1,2,3,4 (Richter Magnitude Scale) – a measure of energy released. Intensity – Roman Numerals – I, II, III, IV (depends on the location) – (PHIVOLCS – PEIS – PHIVOLCS Earthquake Intensity Scale) – to identify the level of intensity.
- Scientists use different ways to find out if a fault is active. One is by checking the country’s historical records. Historians always write about destructive events such as earthquakes. Another is by studying the vibrations, past and present that come from faults. Still another way is by observing the surroundings. For examples, a fault may cross a road and because of that, the road is displaced. Or a fault may cut across a stream and the stream channel is then shifted. Or a fault may slice through mountains and form cliffs or ruptures on the ground surface. This is not to say that anyone can spot an active fault. Scientist need a lot of training to do that
- The Marikina Valley Fault is the fault that is considered to be the most dangerous fault in the country. Why? Because it cuts through almost all the progressive and crowded portions of Manila. Western Philippine Fault can also be found in the water level. In fact, the Western Philippine fault line does not run through land, but in the waters of the Western part of the country Similar to the Marikina Valley Fault line, this fault runs through several provinces in cities from the northern part of the archipelago, down to to the northern part of Davao. The Central Philippine Fault is the root of the earthquake which destroyed the Guinsaugon. Furthermore, it’s also the earthquake that destroyed both Baguio and the Central Luzon part back in 1990. Similar to the Western Philippine Fault, the Eastern Philippine Fault is also a fault found to be beneath the ground. The Philippine Sea is the location where the Eastern Philippine Fault can be found This Mindanao fault runs through the Celebes Sea as well as the Moro Gulf. Luckily enough, if you’re from the city, the Southern Mindanao Fault wouldn’t be anywhere touching you with its dangers. However, the whole Southern Mindanao is at risk when the fault line moves. Even the provinces and cities located adjacent to it is at risk, so, everyone better be prepared. The Philippine Volcanology and Seismology (PHILVOLCS) has yet to release an updated list of inactive faults in the Philippines. However, a well-documented inactive fault was recorded in Pampanga, known as the Lubao fault.
- From California, around Alaska down to Japan, Taiwan, the Philippines and Indonesia. The Philippines is no stranger to Earthquakes but tsunami in the Philippines is extremely rare.
- Prior to March 11, 2011, the last recorded tsunami in the Philippines that actually caused loss of life occurred in the Verde Island Passage (between Batangas and Mindoro Island, affecting Puerto Galera) in the Early morning of November 15, 1994, originating from a 7.1 Magnitude Earthquake, according to the PHIVOLCS.
- 3. Things will happen quickly so make sure that your assistance is alert.
- Answers: A wave was formed by the sudden push. The water level went up. The water represent the sea. The rock represent land. The plastic panel represent the rocks that suddenly move along an underwater fault.
- When the fault under the sea moves the water above it can be affected.
- Tsunami waves involved the whole depth of the sea, from the seafloor to the surface. Far from the shore a tsunami is low maybe just a meter high but it travels at the speed of a jet plane. When the tsunami reaches the shore it slows down but it grows in height. A tsunami is very destructive because the force of the whole ocean is behind it. This is the reason why whole towns and cities are totally devastated after a tsunami attack.
- When you are near the sea and you feel a strong earthquake treat that as warning signal. Run to the highest place you can find, or if you have a vehicle, evacuate inland.
- 2nd day topic
- Primary waves – pressure waves, high velocity, first wave to be recorded by the seismograph during an earthquake. Secondary waves – shear waves, shaking waves, are transfer waves that travels slower than P-waves
- As seismic waves moves though the body of the Earth they performed in diverse form depending on whatever they encounter along the way. Comparatively seismic waves move more and more into the crust, they speed up. This suggest that at the bottom the rocks are denser and in the upper most part of the mantle the waves decrease down and that means that the rock there is partly melted. As the waves enter the core one variety of seismic waves, the S waves, disappears that suggest that outer core is liquid. At particular depths the waves are reflected and refracted that means that the Earth’s must exist layers.
- We often think of Earthquake as something harmful and destructive and the reasons are obvious but earthquake can be constructive also. It helps the scientists figure out what inside the Earth. If you love scenic cliffs, it's possible that an earthquake created one of your favorites. A cliff can form in a location where quakes happen frequently. Earthquake activity may also lead to the formation of land masses at sea. For instance, NASA satellite photos taken in 2013 reveal a new island created after a 7.7-magnitude earthquake ravaged Pakistan. The island formed offshore even though the actual quake occurred around 380 kilometers (230 miles) away from the shore inland. Scientists believe that the island rises up to 20 meters (70 feet) from the water line and has a width of up to 90 meters (300 feet). Its surface consists of rock, sand and mud.