Mystery Challenge 2
How Fast is the Surge Front Wave Going?
Use what you found out in Mystery Challenge 1 to keep on going and find out more about where Miner Ed is.
WOW!! The crevasse Miner Ed fell into was on Bering Glacier just as it surged in 1993. If the ice in the glacier moves down to the terminus during a surge, Miner Ed may come out again, but when?
GLACIER WAVES
Bering Glacier is North America's largest surge-type glacier. It surged in 1993 and again in 1995. During a surge, a type of wave travels down the glacier. A wave in the glacier ice that travels faster than the glacier itself is called a surge front. Though it travels much slower than a wave in water, a glacier wave is similar to an ocean wave.
Imagine yourself bobbing in the ocean in an inner tube. Every once in a while, a wave will roll past you, and although your inner tube is moving in the same direction as the wave, it's not going as fast. Someone on a surf board could actually catch the wave and ride it to the shore but a glacial wave acts more like the person on the inner tube. Parts of the ice surge forward creating a wave that moves faster than the main part of the glacier. The rest of the glacier is probably still moving, but much more slowly than the surge front wave.
Mystery Challenge 2
How Fast is the Surge Front Wave Going? (Continued...)
Computer Figure by James Roush
FACTS:
Imagine a verticle line down the center of the surge-front map.
QUESTIONS:
Ice Worm Hint: Look at any year calendar and count the days between dates or count the weeks and multiply by 7 days for each week. Look at the facts listed above next to the surge front map for distances in meters.
1. Look at a calendar to find out how many days passed between May 19 and August 25. How many days?
24 weeks
98 days
103 days
2. How many kilometers did Bering Glacier surge from May 19 to August 9, 1993?
3. How many kilometers did Bering Glacier surge from June 23 to August 25, 1993?
5.71 miles
3.52 km
6.18 km
4. How many days passed between May 19 and June 23?
SO HOW FAST IS THE WAVE FLOWING?
THAT'S EASY!
FACTS:
The Total distance travelled is 8.8 km
The total number of days is 98 days
One kilometer equals 1000 meters, so first multiply 8.8 by 1000.
How many meters did the surge front travel in 98 days?
How many meters did the surge front wave average each day?
Divide the number from the exercise above by 98 days. What is your answer?
Round your answer up to the nearest two-digit number. Your answer is how fast the wave is flowing. The speed of the wave is also called the the surge wave front velocity!
CONGRATULATIONS!
But Miner Ed is down in a crevasse. He can't ride the wave so will travel slower, like the person in the inner tube instead of on a surf board. The surge front wave actually passes through crevasses, and continues on down the glacier. Miner Ed is still stuck in the crevasse--one with surge waves going right through! Hope he doesn't get sea sick! Will he ever get out?
How fast is Miner Ed traveling?
Will the glacier let him out?
Find out in LEGEND 3--MYSTERY CHALLENGE!
