Balagtasan Essay

The Dynamic Crust, demesnequakes and the priming coats innerWhy is the existences insolence described as being dynamic?Crust- full-blooded didder unwraper zone of landThe cheekiness is ruin of the lithosphere.The flat coats crust is dynamic which essence constantly changing. temblorsVol provokeoesCrustal performances on sequence out(a) zonesOther secern indicates that split of the ashes politics crust hit been moving to different locations for billions of years. bring up pieces of evidence that bring up minor motleys in the Earths crust. Displaced & De stimulateed Rock StrataSedimentary quivers appear to form in horizontal layers. However, observations of the Earths surface indicate that the fender formations of rock have changed with old run lowments. TiltingEarth movement numbering in a change in the position of rock layers, rocks at an inclineFolded StrataBend in the rock layers produced during the mountain twist process Faulting presence of roc k on a crack ( stigma) in the crustDisplaced FossilsDisplaced means moved. naval fossils- remains or imprints of once living nautical organisms such(prenominal) as coral, fish, etc. tack together in sedimentary rock Marine fossils found in layers of sedimentary rock in mountains, often thousands of feet to a high schooler place sea level. These marine fossils found at high elevation suggest noncurrent uplift of rock strata. Sinking or settling of rock strataRock layers that have been moved.Horizontal geological breaking (Faulting)Earth shifts side personal manners on a transform falling out in the crustVertical Displacementum (Faulting)Portion of Earths surface is either uplifted or subsides along a fault or crack. BenchmarkPermanent cement or brass marker in ground indicating a measurable elevation.IsostasyCondition of balance or equilibrium in Earths crust.Since the upper mantle acts want a actually dense fluid, the crustal main offices bollocks on go along of it. Any change in one part of the crust is offset by a corresponding change in an whatever otherwise part of the crust. Example of IsostasyIf a piece of crust loses approximately of its sensible due to erosion, it becomes lighter and floats higher in the mantle. When the eroded material gets deposited, the crust is weighted trim causation that argona to sink sink into the mantle. A nonher isostatic causa.The deposition of 2 miles thick ice on NY during a glacial ice age ca give the argona to subside slightly. This surprised other aras to rise higher in response to the settling under the ice. ulterior after the ice receded or melted, the region responded with gradual uplift causing minor unstable activity or quakes. Give examples of crustal activity and justify where the zones of crustal activity argon turn up. Areas of Crustal ActivityCrustal activities such as seisms and vol loaferoes occur for the approximately part in specific zones or regions of the Earth. These regions be unremarkably along the borders of continents and oceans. These zones mark boundaries or edges of fully grown pieces of the Earths crust called crustal boundaries. ESRT p.5What is an temblor? Explain the difference between an epicentre and a focus of an seism. name properties of the 3 types of temblor pothers and tell the difference between a seismograph and a seismogram. I. quakesSudden trembling or shaking of ground usually ca employ by movement along a break or a fault releasing reinforced up stress When an quake occurs, seismic waves atomic number 18 created and move out in all directions from the focus or draw of origin. The earthquakes focus or point of origin is usually deep beneath the Earths surface. The point on the Earths surface directly above the focus is called the epicenter. Describe properties of the 3 types of earthquake waves and tell the difference between a seismograph and aseismogram. II. Earthquake WavesSeismograph Instrument that detects and records seismic waves. Earthquakes generate several kinds of seismic waves that can be detected by a seismograph. 3 types of seismic waves are p, s, & l waves.L wavesLong wavesDo not pass done the Earth. flap along the surface of the EarthCreate the damage associated with earthquakesP waves particular wavesAlso called compressional because they cause the material through which they pass to vibrate patronage and forth (compress) in the same direction as the wave is traveling. Called particular because they move quickly through the Earth with a strikinger upper than randomnessary waves and therefore are the first waves to r individually a contrasted location. S wavesSecondary wavesAlso called shear waves because they cause the material through which they pass to vibrate at right angles (up & down) to the direction in which the wave is traveling III. Velocities of WavesWhen traveling in the same material, primary waves travel at a greater velocity than secondary waves. So a seismograph exit read the primary waves before the secondary waves arrive. A single seismogram video display the arrival times of p & s waves may be used to determine the distance to the earthquake and its time of origin. The greater the difference in arrival times of the primary and secondary waves, the greater the distance to the earthquake epicenter. Finding the Distance to an Earthquakes EpicenterTo find out how far an epicenter was outside from a location, a seismograph reading or seismogram is necessary that describes the arrival of 2 p and s waves. Determining the train Location of an Earthquakes Epicenter Epicenter location is found by the comparison of differences in travel time of p &s seismic waves. Knowing the separation time between arrival of some(prenominal) p & s waves gives the distance to the point on the Earths surface directly above the earthquake called the epicenter. Since only the distance to epicenter and not direction is known, a circle is drawn wit h the radius contact to the distance. The epicenter is on the circle.To find the actual location of the epicenter you must find the distance from 3 different seismograph move. Why not 2? Draw 3 circles around the 3 seismograph stations and where they intersect is the earthquakes epicenter. The earthquake occurred at a point somewhere below the epicenter and that internal point is called the focus. Scientists wanting to improve accuracy of determination the true epicenter will find the distance from to a greater extent(prenominal) than 3 seismograph stations. Compare and contrast the 2 exceeds for determining the strength of an earthquake. a) The Modified Mercalli surpassBased upon the damage inflicted by an earthquake.This loudness scale ranges from I to twelve with I being felt by few people to cardinal takingsing in total devastation. Modified Mercalli Scale ContinuedAlthough this scale is dummy up used, it is not very precise. Why? Damage inflicted by earthquakes depen ds on some(prenominal) factors besides the strength of the earthquake such as location, type of land, building design & social organization, etc. b) The Richter ScaleA Magnitude scale used to describe the amount of energy ridd by an earthquake. Richter scale orders range from 0 to 9.Each number step up the scale indicates a release of 32 times more energy than the previous step. Earthquakes that are little than 2.5 are not usually felt by people. Approximately 20 study earthquakes in the order of magnitude 7.0-7.9 occur every year and each 5-10 years an earthquake of 8.0 or more will devastate a delegate of Earth. Give examples of dangers to humans from volcanic and earthquake activity. Dangers to Humans from Earthquakes and Volcanoes discern at least 4 of these hazards.Fires (Ruptured gas or power lines)Collapsing buildings/ falling DebrisBroken bridges and roadsTsunamis (Seismic Sea Waves)Lava flows melt and cut backVolcanic ash & poisonous gases make it difficult to breat he king-sized submarine (under pee) earthquakes or those that occur along a coastline may result in tsunamis or seismic sea waves. Describe differences between p and s wave transmission through the Earth and how it creates a rear end zone. VII. Transmission of Earthquake WavesThe velocity of an earthquake wave varies according to compactness of the material through which it is traveling. The greater the density of the material, the greater the velocity. As seismic waves travel through materials of different densities, the velocity of the seismic waves will change. This change in velocity of the wave causes the wave to be bent or refracted. Since the density of the Earth gradually increases with depth, seismic waves tend to increase in their velocity and continually refract (bend) as they travel down into the Earth. residue in P and S Wave TransmissionCompressional or p waves are transmitted through all phases of matter unwavering, liquid or gas. However, shear or s waves are o nly transmitted through solids. This difference provides valuable information for scientists or so the composition and interior structure of the Earth. S waves that penetrate the Earth to the depth of the outer onus group disappear. Since these waves are not transmitted by the outer nitty-gritty, the material of the outer core is assumed to be liquid. Earthquakes generate p & s waves that move out from the earthquake through the Earth in all directions. Seismographs that are located inwardly 102 degrees from the epicenter record both p & s waves. Those seismograph stations that are farther away than 102o do not record all(prenominal) s waves because they are not transmitted through the core. A phone that runs approximately 102o to 143o away from the epicenter records incomplete p nor s waves. Describe a model of the Earths crust and interior. Describe characteristics of both the crust and interior. Crust & Interior PropertiesThere are 4 major Earth zones, three solid ones a nd one liquid. The 3 solid zones are the crust, mantle and inner core.The only liquid zone is the outer core. arrest ESRT p.10Crustal ThicknessThe crust of the Earth compared to other zones is relatively thin, only a few kilometers in average depth. The average thickness of the Continental crust is greater than the average thickness of the ocean crust. Crustal CompositionThe continental crust is composed mainly of felsic flaming rock like granite that is low in density. The oceanic crust is composed mainly of mafic pyrogenetic rock like basalt that is high in density. Interior StructureCrust sits on return of mantle.Mantle accounts for the greatest part of the volume of the Earth. The crust-mantle termination is called the Mohorovicic Discontinuity or the Moho. below the mantle is the liquid outer core and the solid inner core. Interior Composition usher from the behavior of seismic waves and metallic meteorites suggests that the inner portion of the Earth is a high density co mbination of the metallic elements iron out (Fe) and nickel (Ni). Characteristics of Earths InteriorThe density, temperature and pressure of the Earths interior increases with depth. (ESRT p.10). The density ranges from 2.7g/cm3 for the continental crust and 3.0g/cm3 for the oceanic crust to 12.7 g/cm3-13.0g/cm3 for the inner core. Compare theories of continental drift and main office tectonics. Give evidence that support the idea that continents have moved. I. place Tectonics speculation speculation that Earths lithosphere is made of a number of solid plates that move in relation to each other. ESRT p.5Continental DriftTheory that continents are now, as well as in the past, slip positions. Wegener mention that the present continents appear to stop together as fragments of an originally larger landmass, such(prenominal) the same way the pieces of a jigsaw puzzle fit together. This is especially true if the edges of the continental shelves are used as the boundaries. However , oer the years novel evidence has been collected that indicates that approximately 200 gazillion years ago, the major continents were connected and since that time the continents have been moving chiefly apart. The following diagrams show the Inferred Positions of the Continents over the last 458 million years. Label the geological Period for each diagram. Diagrams found in ESRT on page 9. record to Support Idea that Continents Have MovedMany rock layers and fossils can be cor link up across ocean basins. Rock types along with mineral composition and the fossils found in those rocks match up. A good example of this are rocks and fossils found on the east coast of southeastern the States match those found along the west coastline of Africa. Diamonds found in eastern Brazil are very similar to those found in western sandwich Africa. More reason for Continental MovementSome mountain durance appear to be continuous from continent to continent. Example Appalachians and Caledoni anMore Evidence for Continental MovementRock and fossil evidence indicates ancient climates much different from those of today. Examples glacial deposits in tropical regions or coal deposits in Arctic More Evidence for Continental MovementRocks of the ocean basins are much younger than continental rocks. The most conclusive evidence comes from the ocean basins.Explain evidence for sea tier spreading from both igneous ocean rocks and the reversal of magnetised polarity. Evidence to Suggest Sea story SpreadingThere is much evidence to indicate that the ocean floors are spreading out from the mid-ocean ridges. The two major pieces of evidence are related to the age of igneous ocean materials and the reversal of magnetic polarity. a) Igneous sea RocksThe ocean crust is made up mainly of basalt that is formed when magma (molten rock) rises, cools, solidifies and crystallizes into igneous rocks of the mid-ocean ridges. Evidence shows that igneous rocks along the center of the mid-ocean ridge is younger (more late formed) than the igneous rock found farther from the mid-ocean ridge. The age of igneous rock has been accurately decided using radio dynamical dating techniques. This suggests that as unseasoned ocean crust is generated at mid-ocean ridges, the ocean floor widens. Reversal of magnetic PolarityThe strips of basaltic rock that lie parallel to the mid-ocean ridge show matched patterns of magnetic reversals. Check out this animation Over thousands of years, the magnetic gages of Earth reverse their polarities. The magnetic north pole changes to the magnetic south pole and vice versa. When the basaltic magma flows up in the middle of the ridge and begins to cool, crystals of magnetic minerals align themselves with the Earths magnetic field. This alignment of minerals in the rock leaves a recording of magnetic polarity for the Earth at the time of rock formation. When the Earths magnetic field is reversed, the new igneous rocks formed during the reversed polarity period have their minerals aligned in an opposite direction from the previously formed rocks. These changes in magnetic taste are found in rock on both sides of the mid-ocean ridge, indicating that the instruction of the ocean floor is form the center of the mid-ocean ridges outward. Describe the 3 types of plate motion. Identify plate boundaries. Lithospheric Plates and Plate BoundariesThree kinds of plate motion are associated with plate boundaries convergent, divergent and transform. a) Convergent Plate BoundariesConvergent Plate Boundaries- plates clash with each other Ocean Plate Meets Continental PlateIf an oceanic plate collides with a continental plate, the denser ocean plate made of basalt dives down (subducts) into the mantle forming a subduction zone with an ocean trench formed at the surface. At the subduction zone, old crust is consumed by the mantle to create more molten material. The overriding continental plate made of granite forms mountains. An example isthe Andes of South America. Ocean Plate Meets Ocean PlateIf two oceanic plates converge, the older, denser plate will subduct also forming a trench on the surface along with a chain of islands called an island arc. An example of this convergent subduction zone is the Northern and westbound boundaries of the Pacific Ocean. Continental Plate Meets Continental PlateIf a continental plate collides with another continental plate, the edge of both plates are out to(p) up forming folded mountains. An example of this type of convergent boundary is the Himalayas of India. b) Divergent Plate BoundariesDivergent Plate Boundaries- plates move apartA divergent boundary allows rage and magma to flow up from below forming parallel ridges made of new crustal material. An example of a divergent plate boundary like this is any mid-ocean ridge. c) Transform Plate BoundaryTransform Plate Boundary- plates grind easy past each other At this type of boundary, crust is neither formed nor consumed. An example is San Andreas Fault in California.Shallow focus earthquakes are very common at transform boundaries. Plate Tectonic chromosome mapping (ESRT p.5)Although plate motion is only a few centimeters a year, the interactions of the boundaries result in earthquakes, volcanoes and mountain building on a grand scale showing that the Earth is a dynamic system. Explain how mantle convection cells are thought to be the method for moving crustal plates. Mantle Convection CellsAlthough forces exist within the Earth that are hefty enough to move the lithospheric plates, the scientific federation is not in total agreement on the specific machine (method) involved. Convection cell- stream of heated material that is moving due to density differences Evidence suggests that convection cells exist within a part of the mantle called the asthenosphere because of the occurrence of heat flow highs in areas ofmountain building and heat flow lows in areas of shallow subsiding basins. These convec tion cells may be part of the driving force which causes continents to move. What are hot spots? How are they formed?Hot spyHot Spots- places on Earths surface with unusually high heat flow Most hot spots occur along industrious plate margins but some are found within the plates. Hot spots are thought to be caused by magma insurrection up from the mantle producing sites of active volcanism. Wow That was DynamicPrepare for Chapter runningGood Luck* EartHquakes* Sub-topics* How strong is an earthquake?Do you live devout an active fault?Earthquake and tsunamiWhat is inside the earth?* What is an Earthquake?* An earthquake is a shaking of the ground caused by the sudden breaking and movement of large sections (tectonic plates) of the earths rocky outermost crust. The edges of the tectonic plates are marked by faults (or fractures). Most earthquakes occur along the fault lines when the plates glide past each other or collide against each other. * The shifting masses send out shock waves that may be powerful enough to alter the surface of the Earth, thrusting up cliffs and opening great cracks in the ground and cause great damage collapse of buildings and other man-made structures, broken power and gas lines (and the consequent fire), landslides, snow avalanches, tsunamis (giant sea waves) and volcanic eruptions. * How strong is an Earthquake* Earthquakes are measured in two different ways1.) Magnitude2.)Intensity* Earthquake magnitude* Earthquake magnitude is a measure of the energy released by an earthquake, or its size. Because earthquakes deviate a lot in size, earthquake magnitude scales are logarithmic. For a one-step increase in magnitude the amount of energy released increases intimately 32 times. So a magnitude 7 earthquake is 32 times bigger than a magnitude 6 earthquake, and a magnitude 8 earthquake is 1000 bigger. * Earthquake intensity* Earthquake intensity describes how much ground shaking occurred, or how strong an earthquake was, at a parti cular location. Earthquake waves weaken as they travel away from the earthquake source, so an earthquake for the most part feels less strong the foster away from the source you are. * Earthquake intensity* The intensity of an earthquake is determined by observing the effects of the earthquake in different places. Houses, buildings, and other structures are inspected. People are interviewed about what they saw (the cabinet strike down over), how they felt (I was frightened), or what they did (I ran out of the house). * The Modified Mercalli (MM) intensity scale* MM 1Not felt.* MM 2Felt by peeple at rest on upper floors of buildings. * MM 3Felt indoors, like a small hand truck passing hanging objects embroil slightly. * MM 4Felt indoors by many, like a heavy truck passing hanging objects swing, windows rattle. * MM 5Felt outdoors, sleepers awakened, small objects and pictures move. * MM 6Felt by all, crockery breaks, furniture moves, weak plaster cracks. * The Modified Mercalli (M M) intensity scale* MM 7Difficult to stand, noticed by car drivers, furniture breaks, weak chimneys break at roof line, plaster, loose bricks and tiles fall. * MM 8Driving is difficult, ordinary masonry is damaged, chimneys and towers fall, some liquefaction. * MM 9General panic, scant(p) masonry destroyed, ordinary masonry and foundations damaged, liquefaction and landslides. * MM 10Most masonry structures destroyed. Some well-built wooden structuresand bridges destroyed. Dams and embankments damaged, large landslides. * MM 11Few buildings left standing.* MM 12Damage nearly total.* FAULTS* What is a fault?* A fault is a break in the rocks that make up the Earths crust, along which rocks on either side have moved past each other. * The direction of movement along the fault plane determines the fault type. * 3 Major Faults* Normal* Reverse* Strike-slip* Do You Live pricey an Active Fault?* An active fault is one that has moved in the past and is expected to move again. Put in anoth er way, an active fault has generated earthquakes before and is capable of causing more in the future. * Scientists use different ways to find out if a fault is active. integrity is by checking the countrys 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 example, a fault may cross a road and because of that, the road is displaced. * Do You Live Near an Active Fault?* Or a fault may cut across a stream and the stream beam is then shifted. Or a fault may slice through mountains and form cliffs. This is not to say that anyone can spot an active fault. Scientists choose a lot of training to do that. * But along some faults, the effects may be dramatic. Suppose a house was built on a fault. As the ground shifts little by little, parts of the house will be affected. The floor will crack, doors will not close, and the roof may start to leak. * Obviously, it is important to know the location of active faults. As far as possible, no important structures should be built near or on them. Tsunami* What is a tsunami?* A tsunami is a series of waves usually caused by an undersea earthquake that displaces the ocean floor. But a tsunami is not really a wave that moves up and down its actually the ocean moving sideways as a massivesurge or a wall of water. Its also knownas a tidal wave. The Japanese word tsunami means harbor wave.A tsunami can generate waves for 12 to 24 hours. And the first wave is not always Japan, 2011 The Boston land the biggest A tsunami travels across the open ocean at over 500mph, the fastness of a jet airplane. As it reaches shallower water and approaches shore, it reluctants down but grows in height. A tsunami can happen at anytime of day or year. How do earthquakes generate tsunamis?* Tsunamis can be generated when the sea floor abruptly deforms and vertically displa ces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the earths crustal deformation when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position. Waves are formed as the displaced water mass, which acts under the influence of gravity, attempts to regain its equilibrium. When large areas of the sea floor elevate or subside, a tsunami can be created. * What is a Tsunami Earthquake* A tsunami earthquake is an earthquake that triggers a tsunami of a magnitude that is very much larger than the magnitude of the earthquake as measured by shorter-period seismic waves. Such events are a result of relatively slow rupture velocities. They are particularly dangerous as a large tsunami may arrive at a neighbouring coast with little or no warning. a tsunami earthquake is that the release of seismic energy occurs at long periods (low frequencies) relative to typical tsunamigenic eart hquakes. Earthquakes of this type do not generally show the peaks of seismic wave activity associated with ordinary events. A tsunami earthquake can be defined as an undersea earthquake. * What is inside the Earth?* Earths Layers* CrustThe crust is the first layer of the earth. It is split up intotwo parts the continentalcrust, and the oceanic crust.* MantleThe mantle is the second layer of the earth. It is split up into two different parts, the lithosphere (which is the top part) and the asthenosphere (which is the bottom part). * Earths Layers* Outer coreThe outer core is a liquid made up of iron and nickel. The depth of the outer core is 2, 890. This is one of thethree layers that is putting pressure on the inner core. * inner(a) coreThe Inner crust is the second thinnest layer. The inner core is hotter than the surface of the sun. The inner core is made out of iron and nickel. It is 5159 to 6378 km thick. * Earths Layers* The Earth is formed of three concentric layers the core, the mantle and the crust these are uninvolved by transition zones called discontinuities. * Mohorovicic discontinuity* Gutenberg discontinuity* How the seismic waves travel* The shaking starts from the focus and spreads out. You can get an idea of how this happens by throwing a pebble into a pond. See the ripples that move out in circles? The vibrations from the focus are something like that. * The vibrations are more properly called seismic waves. As seismic waves travel through the body of the Earth, they behave in different ways, depending on what they encounter along way