As lava cools and contracts, geometric columnar joints may form.​

Mountain valleys that are U-shaped are most likely the result of erosion by a valley glacier. ​

The point on the earth’s surface immediately above the focus is the seismic center.

A glacier covering at least 50,000 km2 and unconfined by topography is classified as a(n) ____.​

Thick bars of gravel and large boulders provide evidence for massive flooding cause by the failure of large pluvial and proglacial lakes.​

Both P-waves and S-waves can pass through ____. 

A ______ stress is caused by forces pulling away from one another. 

_____ meanders are meanders that retain their sinuous pattern as they cut vertically downward below the level at which they originally formed. 

Harry Hess proposed that the _______. 

A metamorphic rock is similar both in mineralogy and texture to its parent rock.