Name Joshua Fernandez Learning Unit 5 Tsunami Review Questions This assignment is designed to assess your understanding of Unit 5 and includes some of the Questions for Review at the end of Chapter 5 from your text plus a few additional questions Each question 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 evaluation and grading through the assignment tab by or before the due date 1 How many tsunami waves are generated when an abrupt disturbance such as an earthquake vertically displaces the water column Around 10 or more 2 Of the three main types of fault movements strike slip faults normal faults and reverse thrust faults which can and which cannot cause tsunami Why Normal and thrust faults can strike slip faults cannot Normal and thrust faults do displace water and strike slip faults do not displaced water 3 How dangerous are tsunami waves in the open ocean And why These waves are not dangerous in open ocean because the height of the waves are smaller than the wave length Also time between crests is long 4 Which is the more dangerous location for a tsunami a straight stretch of open coast or a bay Why the wave to rise A bay because it focuses the wave making the water go into a narrower area causing 5 What is often the first indication of the arrival of a tsunami at the coast And fast drop in ocean sea level 6 For a subduction zone earthquake off the coast of Oregon or Washington how long would it take for a tsunami wave to first reach the coast About 20 minutes or less 7 What are the approximate times between tsunami wave crests From 10 35 minutes it is usually 30 minutes on average 8 Which wave of a major tsunami is likely to be the highest first fourth tenth Fourth 9 In December 2004 a pair of closely related natural disasters killed tens of thousands of people Case in Point Lack of Warning and Education Costs Lives Sumatra Tsunami 2004 a What was the initial event not the one that killed most of the people A major earthquake b Where specifically was that initial event It was by the southwest coast of Sumatra c What secondary event the one that killed most of the people was caused by the initial event noted above A tsunami secondary event d Explain concisely and in detail exactly how the initial event was related to the A tsunami was caused by the initial earthquake because of the fault movement on the ocean floor pushing a lot of water up 10 There have not been any very large earthquakes on the subduction zone of the coast of Washington and Oregon in hundreds of years Explain why not and what are the implications based on records of past events Because the subduction zone is locked and the last earthquake was in 1700 Since major earthquakes happen rarely a major one could happen in the future 11 On low lying coastal flats near Anchorage Alaska the foundations of buildings dropped below sea level during the giant 1964 earthquake Decades later their foundations are again above sea level Case in Point Subduction Zone Earthquake Generates a Major Tsunami a What type of tectonic boundary caused the earthquake and what plate motions are involved Subduction zone boundary the ocean floor is going under and descending b Explain what tectonic forces led to the ground sinking and later rising Due to the subduction zone being locked descent of the ocean floor pulled down the continental margin release of the boundary during the earthquake allowed the ground to drop all of a sudden and allowed the sea to move in years and decades later the edge of the continent is rising since the subduction zone is locked once again 12 What type of event has repeatedly generated high tsunami waves in Lituya Bay of southeastern Alaska Be specific Case in Point Immense Local Tsunami from a Landslide Lituya Bay Alaska 1958 A large landslide that was caused by a nearby earthquake 13 List some of the ways volcanoes can generate tsunami Volcanic earthquakes undersea eruptions landslides lahars pyroclastic flows 14 How are tsunami waves in the Atlantic Ocean likely to be generated Not likely but it is still possible it is because of the lack of subduction zones 15 Why are even good swimmers often killed by tsunami waves Because of the speed and pressure of the wave along with the objects the wave carries in its path
View Full Document
Unlocking...