Worried about slipping on the ice? In Alaska, that's exactly what these USGS scientists study! Strike-slip fault systems shaped by tectonic forces, that is! A strike-slip fault occurs when two massive chunks of the Earth's surface move, collide, and then slide past each other horizontally. The strike-slip fault system in Alaska shown here is covered in ice. Scientists monitor this area closely since it has caused some of the biggest earthquakes ever recorded on U.S. soil, including a magnitude 7.9 earthquake in 2002. This massive event ruptured along the Denali-Totschunda fault system, rivaling California's San Andreas Fault in length and seismic significance. In the Denali-Totchunda fault system, the Pacific Plate collides with North America, leading to significant seismic activity and shaping the state's dramatic landscape. The Denali fault, a major geological feature, shows evidence of millennia of stress and movement, moving roughly at a rate the width of a paper clip each yea...