Deadliest Earthquakes Questions Waite
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Purdue University *
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186
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Geology
Date
Apr 3, 2024
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docx
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Uploaded by DeanHornet3553
Nova Deadliest Earthquakes
Haiti
1
Describe the devastation that occurred in Haiti in January 2010. Answer: 233,000 people are killed, millions
more injured or orphaned. 2
How did scientists know that an earthquake was inevitable in Haiti? Answer: Haiti lies directly about some massive faults, the North American plate and Caribbean plate are meeting. Last major earthquake was about 250 years ago. Since then scientists have discovered they are causing stress to build up as the plates slide past each other at about 7mm per year. Described as a rubber band. Six feet of stored strain as they did the math, which is the equivalent of 100 atom bombs. 3
Which type of boundary caused the Haitian earthquake? Answer: Transform/slip
4
How fast do plates move? What is the source for the movement? Answer: Same speed as your fingernails grow. The Earth’s internal heat moves the huge plates. Above the hottest zones, molten rock rises and solidifies, creating new crust. The new crust jostles for space, forcing crust on cooler edges to grind against other plates or push beneath them.
5
The energy released by earthquakes is equivalent to ________________________. Answer: Many thousands of nuclear bombs going off. 6
How many times stronger is a magnitude 8.0 earthquake than none at all? Answer:120
7
The faster the movement of plates the more frequent the earthquakes. (True or False) California
8
What is the name of the main fault that we have in California? Answer: San Andreas
9
How long is the fault in California and does it move relatively fast or slow? Answer: It moves faster about an inch a year, 800 miles long. 10
The Northridge Earthquake occurred in 1994 on the San Andreas Fault was a magnitude 6.7 but caused _______
60
_____deaths and __
20
_______ billion dollars worth of damage
11
What is the Great Southern California Shakeout and why did people in Southern California go through this exercise? Answer: They created the scenario of a 7.8 magnitude earthquake on the San Andreas fault just east of Los Angeles to see what the devastation would be. They figured out most would be without water, there would be thousands dead, millions displaced, $200 billion in damages. 12
Why are scientists drilling in the desert of Southern California? Answer: To find underground seismic activity that could warn of the next earthquake. Chile
13
February 2010 there was a massive earthquake in Chile that was a magnitude ____
8.8
_______. It was the 5
th
largest earthquake recorded. Describe the devastation of this earthquake. Answer: Half a million homes destroyed, hundreds dead. It also was so violent it accelerated the Earth’s rotation, knocking a millionth of a
second off the length of the day. 14
What type of boundary is found between the Nazca and South American Plates? Answer: Convergent Boundary Subduction Zone
15
What was found on the beach to demonstrate to how much power the earthquake had? Answer: A child’s sock that was 20 feet above their heads. 30 feet above sea level. 16
When massive amounts of energy are released under the water at subduction boundaries, ___
Tsnunamis
___________ can occur. 17
Why are tsunamis to destructive? Answer: A 30ft wave can exert energy equivalent to the weight of a tank. Destroys foundations, currents just push and push in same direction which rip everything in it’s path.
North America – Cascadia Fault
18
Which areas are affected by the Cascadia Fault? Answer: Oregon and Washington
19
Why are scientists collecting and storing mud samples at Oregon State University and how do they tell earthquakes’ stories? Answer: They collect core samples from the subduction fault off the coast as undersea earthquakes create huge landlsides underwater that coat the sea floor. These sandy deposits tells the stories of the undersea earthquakes and their patterns. These also are acting as tape recorders recording everything that happens on the sea floor. By taking these samples they can see the recording of each of the earth quakes, their patterns, through the patterns of the sediments. 20
A Mega thrust is expected in the next 50 years in Cascadia which will result in a massive ___________
earthquake
__________ and a _____
tsunami
________________. 21
What subtle indicators are scientists observing in the forest that might be excellent predictors of future earthquakes? Answer: Every 14 months tiny tremors vibrate the ground for weeks at a time. Predicting and Preparing for Earthquakes
22
Why can earthquakes trigger other earthquakes and where was this observed in 2010? Answer: Energy released by one quake can travel along a fault, causing it to unfasten like a zipper. This happened in Mexicali April 2010. 23
Which wave arrives first? Second? Answer: First is primary or P-Waves, second is S-waves or surface waves. 24
How can early P-wave warning systems help decrease death and destruction in earthquake prone areas? Answer: The P-wave must be detected and the alert sounded in a split second before the destructive S waves
follow.
25
Why where there so many more deaths in Haiti than in other areas with large populations? What are some strategies that builders can use to decrease death and destruction in earthquake prone areas? Answer: Most Haitians were killed by collapsing buildings. Engineers now use enormous shake tables to test new designs. Their huge hydraulic pistons mimic powerful tremors. Results are helping revolutionize building designs. Damaging Earthquake motion is minimized using deformable or floating foundations or offset by complex counterweights. Skyscrapers are built with confidence, in some of the most earthquake prone regions on the planet.
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