Name: _____Caleigh Kehoe______ Learning Unit 4: Earthquake Review Ques>ons This assignment is designed to assess your understanding of Unit 4 and includes some of the Ques>ons for Review at the end of Chapters 3 and 4 from your text plus a few addi>onal ques>ons. Each ques>on can be answered in one to two sentences. Please limit yourself to a maximum of three sentences. Access the assignment, complete it with ANSWERS IN A DIFFERENT COLOR FONT as a separate file, and send it back for evalua>on and grading through the assignment tab by or before the due date. 1. What is meant by the “elas>c rebound theory”? The elas>c rebound theory is an explana>on for how energy is spread during earthquakes. 2. What is the difference between the epicenter and the focus of an earthquake? The focus of an earthquake is the exact point underground where the earthquake rupture starts measured in la>tude/longitude, and also depth. The epicenter is the la>tude/longitude point on the ground directly above the focus. 3. Extension of the Earth’s crust generally causes what type of fault or faults? What type of plate boundary would produce such a fault or faults? Extension of the Earth’s crust generally causes normal faults, while a ri[ or spreading would produce such a fault or faults. 4. Compression of the Earth’s crust generally causes what type of fault or faults? What type of plate boundary would produce such a fault or faults? Compression of the Earth’s crust generally causes reverse or thrust faults, while ocean-con>nent or con>nent-con>nent collision would produce such a fault or faults. 5. What is the mo>on of a P-waves? an S-wave? Surface waves? P waves can travel through solids, liquids, and even gases. S waves shake the ground in a shearing, or crosswise, mo>on that is perpendicular to the direc>on of travel. 6. Which type of earthquake waves do the most damage? Surface waves are the slowest, but they do the most damage in an earthquake as they travel along the surface. 7. In what order do seismic waves arrive to distant loca>ons?8. How do seismologists determine how far away an earthquake was from their seismograph? They determine the >me lag between the P- and S-wave arrival and knowing the different veloci>es of those waves, calculate the distance. The >me lag increases the farther they are form the earthquake. 9. How do seismologists determine the loca>on of an earthquake epicenter? They determine the distance of the earthquake from at least three seismograph of quite different loca>ons and draw circles of distance from each seismograph. The earthquake was at the intersec>on of the three distance circles. 10.What does the Richter Magnitude Scale depend on? The Richter Magnitude Scale depends on the maximum amplitude of earthquake waves on the seismograph. 11.How much greater energy is released by a magnitude 6 earthquake than a magnitude 5 earthquake? How much greater energy is released by a magnitude 7 earthquake than a magnitude 5 earthquake? The amount of energy released, however, increases by a factor of about 32. Looking at the same magnitudes, a magnitude 6.0 earthquake releases 32 >mes more energy than a magnitude 5.0 and a 7.0 quake releases 1,000 >mes more energy than a 5.0 quake. 12.What are the three main factors that affect moment magnitude? The three main factors that affect moment magnitude are shear strength of the rocks displaced, total surface area of rocks ruptured by the fault movement, and average slip distance on the fault. 13.What does the Mercalli Intensity Scale depend on? Mercalli Intensity Scale depends on how much damage occurred in the area. 14.In addi>on to the amount of damage, increases in what factors go along with an increase in earthquake magnitude? In addi>on to the amount of damage, increases in fault offset, length of fault ruptured, accelera>on off the ground, >me of shaking, velocity of mo>on of the ground go along with an increase in earthquake magnitude. 15.Why are structures built on so[ sand or mud o[en destroyed in an earthquake when nearby structures built on bedrock remain essen>ally undamaged? Bedrock shakes with small amplitude vibra>ons, the so[ sediment shakes with stronger (larger amplitude) vibra>ons, meaning greater back and forth distances.16.What is liquefac>on? Liquefac>on takes place when loosely packed, water-logged sediments at or near the ground surface lose their strength in response to strong ground shaking. Liquefac>on occurring beneath buildings and other structures can cause major damage during earthquakes. 17.What kinds of structural materials make dangerously weak walls during an earthquake? Bricks, concrete blocks, stone, or adobe (mud) make dangerously weak walls during an earthquake. 18.What type of wall strengthening is commonly used to prevent a building from being pushed over laterally during an earthquake? The diagonal beams is commonly used to prevent a building from being pushed over laterally during an earthquake. 19.What can be done to a building, either during construc>on or a[er, to reduce the shaking of the building during an earthquake and therefore reduce the possibility of severe damage? By using base isola>on pads between the building and its founda>on, the base isola>on pads act as shock absorbers to minimize transfer of ground shaking to the building. 20.Freeway overpasses o[en collapse in a strong earthquake, even though their supports are concrete and heavy duty steel reinforcing bars. Why? Shaking in the earthquake cracks and crumbles the concrete; that leaves the rebar without lateral support so it bends and the freeway collapses. 21.Why are building fires so hard to fight a[er an earthquake? Most earthquake damage results from the sudden release of energy in the form of seismic waves (wave mo>on) and surface rupture (physical slippage) of the earth's crust. Mul>ple post-earthquake fires and physical damage can delay fire service responses and reduce or exhaust water supples. In addi>on, flammable gas or ignitable liquid releases and fire protec>on impairments create significant post- earthquake fire hazards. 22.List several of the precursors that have been used to indicate that an earthquake may be coming. Some indica>ons that an earthquake may be coming are micro earthquakes, changes in groundwater level, increase in radon in water, strange animal behavior.23.There has been at least one highly successful
View Full Document
Unlocking...