Earthquakes at the Nanoscale
In 2008, Sichuan province in China experienced a massive magnitude-7.9 earthquake caused by the collision of the Indian-Australian and Eurasian plates along the Longmenshan Fault. The earthquake, which has been ranked as the 21st deadliest quake of all time, flattened four-fifths of the structures in the affected area, destroying whole towns and villages and leaving millions of people homeless. Almost 90,000 people were killed.
Kaiwen Tian, who was born and raised in Sichuan, distinctly remembers hearing news of the quake. Although he didn’t personally know anyone who was killed, many people he knew had family or friends who died in the quake. This, Tian says, is a huge part of the reason he decided to study earthquakes.
In collaboration with Robert Carpick and David Goldsby, Tian, who graduated from Penn in 2017 with a doctorate in physics, recently published a paper in Physical Review Letters which attempts to tackle these devastating natural phenomena by investigating the laws of friction at the smallest possible scale, the nanoscale.
“A grand challenge goal for the geophysics community,” says Goldsby, Associate Professor of Earth and Environmental Science, “is to come up with fundamental laws where not only do we know the form of the equations but we know all the coefficients as well: the numerical constants that go into the equation that governs friction.”