SCIENCE 8 - QUARTER 2 - WEEK 1 - EARTHQUAKES AND FAULTS - MELC-BASED

[Music] are you ready let's get started number one philippines is located along the pacific ring of fire [Music] excellent the correct answer is true the ring of fire refers to the region around the pacific ocean that is commonly hit by earthquakes and volcanic eruptions some of the countries in the pacific ring of fire are japan indonesia and the philippines number two earthquakes are not associated with faults [Music] you are right the statement is false earthquakes occur when rocks along a fault suddenly move number three a fault is a break in the earth's crust and along the break no movement has taken place [Music] correct that is false it is true that the fault is a break in the earth's crust and along the break significant movement has taken place but how do falls produce tweaks we will learn that later number four energy from inside the earth exerts a force on the rocks [Music] that's right energy from inside the earth exerts a force on the wraps along faults this energy from inside the earth makes the rocks bend using a model later we will see how this happens number five when a portion of the land sinks a mountain is formed [Music] that's right the statement is false mountain is a large mass of land that rises above the ground while the valley is a lower part of the land between two higher parts which might be mountains or heels did you get the correct answer then you are doing great earthquake is used to describe the sudden shaking and trembling caused by the sudden release of energy from inside the earth try to look at these pictures what do you see why do we need to learn earthquakes strong earthquakes have caused countless deaths all over the world and no one can stop quakes from happening no wonder scientists have been working very hard to find a way to predict when an earthquake occurs [Music] the study of an earthquake is called seismology the scientists who study earthquakes are called seismologists in the philippines the national agency concerned in monitoring the earthquakes and fault movements is the fivos or the philippine institute of volcanology and seismology there are things that people can do to avoid or reduce the loss of life and damage to property the first step is to have a clear understanding of the occurrence of the earthquakes now let us watch this news clip and try to think carefully about it what would you feel if you are living in these areas an earthquake is one of the most frightening things that anyone can ever experience you grow up believing that the earth is rock solid and steady but then the ground suddenly shakes and you do not know what to believe anymore earthquakes are associated with faults when a fault suddenly moves an earthquake occurs do you know what a fault is let us perform this activity a fault is set up in this activity we will be needing two sheets of cardboard fine sand ruler sheets of paper or newspaper the first thing that we need to do is to spread the sheet of paper on a table [Music] then arrange the two sheets of cardboard edge to edge four sand along the boundary of the two sheets with a ruler flatten the top of the sand and make two parallel lines [Music] now move the sheets slowly in the opposite direction [Music] now let us try to answer these questions as you move the sheets what is formed in the sand a crack is formed in the sand or we can also see that a break is formed in the sand [Music] what happens to the lines [Music] we can see that the lines moved it is shifted or displaced try to look at this picture carefully maybe you are thinking that the road was originally in one piece but the road is no longer continuous there is a cut across the road and now there are two sections one section has move with respect to the other compare what you see in the picture and what you saw in the activity is there something in the picture that looks like what was formed in the activity do you see anything similar based on the activity and the picture you can probably guess what a fault is by now fault is a break or a fracture in the earth's crust and along the brick significant movement has taken place the word break refers to a crack in the ground the world crust refers to the outermost layer of the earth we live on the surface of the crust significant movement means the rocks have been displaced or shifted considerably [Music] this time get the box and cut it in the middle [Music] place one box over the other one put sand in the nested boxes shake the box side to side so that the surface of the sand will become level [Music] now we will slowly pull the sides of the boxes and observe we can see that the two parallel cracks formed in the sand let us continue to pull the box cover and observe the sand in the middle of the crack subsides or move down forming a depression this simulates what happens when the ground is pulled apart by forces within the earth [Music] falls form a portion of the land sinks and a valley is formed [Music] now let us reassemble the box covers as before do not forget to make the surface of the sand flat this time let us push the sides of the box covers toward each other and observe what happens as we can see the opposite happens instead of the sand sinking the sand forms a tiny ridge unfortunately this model does not show a craft in the sand that would represent a fault in the real world a fault is formed when the ground is squeezed by forces from inside the earth a portion of the land is pushed up and mountains are formed [Music] there are three types of faults the normal fault the reverse fault and the strike's default in the normal fault the rock layers in the earth's crust are pulled apart and gravity causes one section to move downward in relation to the other [Music] [Applause] while in the reverse fault the rough layers in the earth's crust are squeezed together and the force pushes one section upward about the other [Music] then the strike sleeve fall forms when the rock layers on the opposite sides of the falls slide past each other horizontally [Music] but how do falls produce quakes now that you have an idea of how faults look let us learn how earthquakes occur along faults let's do another activity stick and sleep this will show us how earthquakes are related to falls in this activity two small boxes are needed the cartons that fruit juice drinks are packaged in are perfect scotch tape or masking tape rubber band and a paper clip you can also try this at home let's start first attach the rubber band to the paper clip [Music] then attach the paper clip to one end of one box [Music] place the boxes side by side lightly tape the two boxes together then put a toy house on the box with the rubber band remember do not stick the tape on the boxes too much the tape is meant to come off then third hold the box without the rubber band in place with your other hand slowly pull on the rubber band the rubber band should be pulled forward and horizontally not sideways upward or downward it is expected the box will not move at first because it is steep to the other box question what happens to the rubber band you are correct the rubber band stretches now keep on pulling on the rubber band [Music] question what happens to the box attached to the rubber [Music] band right the box jerks forward [Music] what about the house what happens to the house you're correct the house falls over which is fault in this setup if you think that the fault in the setup is the boundary between the two boxes then you are correct as the box jerks forward this simulates the sudden movement that occurs along a fault in this activity the tape represents friction in real life do you still remember what friction is you are right friction is the resistance to motion of one object moving relative to another if the tape is too sticky it will never come off no matter how much rubber band is pulled but since we tape it on just enough then the box jerks free from the tape as we pull the rubber band imagine the boxes as the ground and the boundary between them as fault in real world terms this is what happens energy from inside the earth exerts a force on the rocks along faults but the rocks do not move right away because of friction [Music] the roughness of the rocks keeps them from slipping past each other but when the limit is reached the rocks suddenly sleep and an earthquake occurs [Music] some scientists describe this process as a stick and slip at first the rocks are stuck together due to friction later the rocks suddenly slip generating an earthquake every time a fault slips the earthquakes in our activity there was a sudden jerk but no shaking the boxes did not shake as in a real earthquake can you make your false model if so what materials will you use can you also demonstrate to us your fault model [Music] although major earthquakes can kill thousands of people and can cost a lot of money for damage to repair earthquakes can also have positive benefits for humans it helps us to understand nature it also allows scientists to study the earth's inner layer and understanding earthquakes helps us to prepare and respond to such devastating events if we have a clear understanding of the occurrence of the earthquakes we can avoid or reduce the loss of life and damage to property let us have a self check try to answer the following questions grab a paper and a pen then write down your answer you may pause the video if you need more time [Music] number one it is described as the sudden shaking and trembling caused by the sudden release of energy from inside the earth a fault b friction c earthquake d seismology [Music] number two which type of fault is this a reverse b normal c strike slip d stick and slip [Music] number three the study of earthquakes a fault b earthquake c seismology the friction [Music] number four earthquakes happen along a fault line which of the following is not true about faults a it can be found in the land b it is where fault cyclone starts see it is the break in the earth's crust d none of the above [Music] number five this is the process refers to the fast movement between two sides of a fault wherein the friction is overcome resulting in a sudden movement or shaking of the ground a stick and shake b stick and bend c stick and vibrate d stick and slip [Music] number six earthquakes are common occurrence in japan indonesia and in the philippines why is this so a they are located near the equator b they are considered archipelagic countries c they are found within the pacific ring of fire and d they are surrounded by seas [Music] number seven what will most likely happen every time a fall sleeps a there will be no movement at all b the rocks will suddenly sleep and will generate an earthquake c the rocks will be stuck together d there will be movement right away [Music] number eight what philippine agency is concerned about monitoring fault movement a philippine institute of volcanology and seismology or fevox b philippine atmospheric geophysical and astronomical services administration or pagasa c department of labor and employment or dole d department of environment and natural resources or danr [Music] number nine energy from inside the earth makes the ground move which of the following is the reason why there is no movement right away a friction causes a delay in the movement of the ground b the rapid release of energy causes a delay in the movement of the ground see there is no movement right away because of the vibration of the rocks d there is no movement right away because of the bending of the rocks [Music] number 10 which factor keeps the rocks from sleeping past each other a the depth of the rocks b the roughness of the rock c the arrangement of rocks d the bending of the rocks [Music] now let us check your answers [Music] congratulations i am sure that you've learned something new today thank you for watching [Music]

Channel: Jennalyn Mendoza

Views: 122,899

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Id: HKLlB8n2eE8

Length: 21min 7sec (1267 seconds)

Published: Thu Oct 22 2020