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Unformatted text preview: 2/20/2008 1 Natural Disasters Example Questions for TEST 1 Natural Disasters Response and Mitigation Spring 2008 Example Questions for TEST 1 1 Revised Feb 20 2008 Natural Disasters A few examples What was the most catastrophic natural disaster in the US during the 20th century (1900 to 1999) in terms of loss of life? The interpretation of "risk" that we discussed (from FEMA) is The phases of emergency management (FEMA) are 2 Revised Feb 20 2008 ANSWERS 2/20/2008 2 Natural Disasters Pyroclastic Flow poses threat – or does it? 16 km 8 km 3000 4000 m 4 km A x Mt Ash 1. A pyroclastic flow originating at the summit of Mt Ash threatens the town at D. The Heim coefficient for the pyroclastic flow is estimated to be 0.20. The 4000 m 1,000 m Datum x x D B C 1000 2000 3000 1000 2000 3000 4000 m Mt. Ash x Green Hill at C is 500 m high and 4 km long 2. Determine the velocity and the kinetic energy of the flow at point B 3. Determine whether the flow reaches the town at D, and with what velocity. If the flow does not reach D, determine where it stops 4. Explain how the Heim coefficient for a given locality is determined 5. Explain why the Heim coefficient for pyroclastic flows varies from locality to locality 3 Revised Feb 20 2008 Natural Disasters Pyroclastic Flow poses threat – or does it? ANSWERS A pyroclastic flow originating at the summit of Mt Ash threatens the town at D. The Heim coefficient for the pyroclastic flow is estimated to be 0.20. The Green Hill at C is 500 m high and 4 km long 1. Determine the velocity and the kinetic energy of the flow at point B 2. Determine whether the flow reaches the town at D, and with what velocity. If the flow does not reach D, determine where it stops UNITS Mass of slide M Gravity 9.81 m/s2 Take datum at 0 elev. Elev at A 4000 m Energy at point A 4000Mg m x g x M Heim H = 0.2 Energy lost to friction over 8 km from AB 1600Mg m x g x M Total energy at B is equal to 2400Mg m x g x M Gravitational potential energy at B 1000Mg m x g x M Kinetic energy K at B is equal to 1400Mg m x g x M Velocity at B 2 2 8 . 9 2800 2800 2800 2 m g M Mg M K v × = = = = determine where it stops 3. Explain how the Heim coefficient for a given locality is determined 4. Explain why the Heim coefficient for pyroclastic flows varies from locality to locality 4 Velocity at B 166 m/s Energy lost to friction over 16 km from AD 3200Mg m x g x M Total energy at D is equal to 800Mg m x g x M Gravitational potential energy at D 1000Mg m x g x M Kinetic energy K at D is equal to 200Mg m x g x M Negative K so does not reach D Set K = 0 Change in elev y if slide ends at elev 1000 3000 x = y/H 15000m Therefore slide stops at 15 km exactly 2 s M Revised Feb 20 2008 ANSWERS 2/20/2008 3 Natural Disasters Unit Hydrograph 1. What is a unit hydrograph 2. Calculate the direct runoff flow and the unit hydrograph for the case below hydrograph for the case below 3 What is a unit hydrograph used for?What is a unit hydrograph used for?...
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 Spring '08
 M.MAULDON
 pH, Mount St. Helens, 1980 eruption of Mount St. Helens, Mount Saint Helens, Lava dome, H. Pyroclastic

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