Great talk from Ronni Grapenthin of UC Berkeley’s Seismology Lab. Dr. Grapenthin discussed how he uses high-precision and high data-rate GPS measurements to link the motions of the Earth’s crust to geophysical processes, including earthquakes and volcanic eruptions.
One of the neatest things he showed was a video of GPS displacements during the huge Tōhoku earthquake in Japan three years ago (above). The left panel shows lateral displacement (the largest arrows reflect only a few meters of displacement, not hundreds of kilometers, as it may seem), while the right panel shows vertical displacement. The waves associated with the earthquake and an aftershock are shown pretty dramatically, as they propagate through the Earth’s surface away from the earthquake source.
In the near-term, Grapenthin is helping to develop an early warning system for earthquakes in California using these kind of GPS data, which could help save many lives.