Time-lapse monitoring of seismic velocity at volcanic areas can provide unique insight into the property of hydrothermal and magmatic fluids and their temporal variability. Taira and Brenguier (2016) established a quasi real-time velocity monitoring system by using seismic interferometry with ambient noise to explore the temporal evolution of velocity in the Lassen Volcanic Center, Northern California. Read more
About 40 tracking stations all over the world are currently operational for Satellite Laser Ranging (SLR), a very precise geodetic technique. Otsubo et al. (2016) ran a unique simulation to find the optimal place of a future SLR station. The answer depends on a geodetic product and one example is shown for the center of gravity of the Earth: the X and Y components are largely improved by a high-latitude station especially in the southern hemisphere, whereas the Z component is improved by a low-latitude station. Read more