Lava comes in two ‘flavors.’ Scientists may have finally figured out why
While on a family vacation in 2018, Jenny Suckale was rambling across an old Hawaiian lava flow when an abrupt change in the jet-black rocks caught her eye. On one side was the smooth, undulating lava type called pahoehoe (pronounced pah-hoy-hoy); on the other was the sharp, jagged kind known as aa (pronounced ah-ah). Ever since that day, a deceptively simple question has nagged at Suckale, a geophysicist at Stanford University: What causes the dramatic transformation in texture, seen in lavas worldwide? Over the years, scientists have pointed to a slew of possible culprits: the speed of a flow, the slope of the ground it oozes over, or the amount of lava erupted. But no single factor has explained the shift. Now, by modeling the dynamics of lava flows, Suckale and her colleagues have offered up another explanation:...