Author Question: What was the first evidence that suggested the Earth's crust might be broken into pieces? a. Echo ... (Read 41 times)

anshika · **on:** Aug 22, 2018

What was the first evidence that suggested the Earth's crust might be broken into pieces?
a. Echo soundings aboard the Meteor
b. Plotting of deep earthquakes in the Pacific Ring of Fire
c. Radiometric dating
d. Radioactive decay

Question 2

What did Harry Hess and Robert Dietz suggest the cause of the continents moving was?
a. Convection currents
b. Radioactive decay
c. Conduction
d. Gravity

amanda_14 · **Reply #1 on:** Aug 22, 2018

Answer to Question 1

ANS: B
The deep earthquakes were plotted at the edges of the Pacific. The large area of those earthquakes was
aptly named the Pacific Ring of Fire. Seismographs revealed a worldwide pattern of earthquakes and
volcanoes. Information can be found in the section Wegener's Idea Is Transformed.

Answer to Question 2

ANS: A
New crust that is being formed moves outwards from the source. Hess and Dietz suggested that new
seafloor develops at the Mid-Atlantic Ridge and that this same force causes continents to move as
well. The motion would powered by convection currents. Later this hypothesis would be called
seafloor spreading. Information can be found in the section The Breakthrough: From Seafloor
Spreading to Plate Tectonics.