1)What percentage of earth lives within few tens of kilometers of ocean?
a)20 b)50 c)80 d)10 e)90
2) new sea floor is created at convergent margins where crust is destroyed(True or False)
3)what percentage of earth surface is below sea level? a)10 b)30 c)70 d)All of earth surface below sea lebel
4) the focus of an earthquake a)is the same thing as the epicenter b) can be located using only one seismograph c) the primary point of rupture in the earth crush d)the point on the earth surface above the fault rupture
5)when one plate subducts underneath another, which of following do NOT form?a)large explosive volcanoes b) deep ocean sea trenches c) mid ocean ridges d) atolls
6)A possible "driving force" for plate motions is: a)volcanic eruption at hot spots b) shifts in earths magnetic field c) convection in the mantle d) the weight of subducted continents pulling downward
7)Do you expect the ocean to mix by the convection? Why or why not?
8)Why is sediment cover extremely thin close to the mid ocean ridge system?
9)If you find sediment that is 40 million years old on the sea floor, what does this tell you about the age of the oceanic crust in this location?
10)Explain how island chain of Hawaii illustrates pacific plate is moving?
11)Why are pillow basalts most common type of rock on earth?
12)what two differences in oceanic crust and continental account for relative difference in vertical positions?