Hannah Mark grew up on the solid Manhattan schist left behind by the Taconic orogeny about 450 million years ago. As a child, she had a pet rock named “Potato Rock,” which looked, if you squinted, sort of like a root vegetable. Many years and many geology classes later, she learned that Potato Rock was a chunk of dirty quartz and not, in fact, a fossilized potato. When she is not contemplating seismic data, she may be singing soprano in the Falmouth Chorale, learning English longsword dances, and baking bread with Lord Kelvin, her sourdough starter. She also enjoys slow-motion surfing on the North American plate as it inches west-southwest at a rate of about 2.3 centimeters per year. Her Ph.D. advisors are WHOI geophysicists Dan Lizarralde and Mark Behn, and her mentor on this article was Rhonda Moniz, editor of Ocean News & Technology magazine.