Sun, moon and sea as part of a 'seismic probe'

Using a single seismometer, researchers have shown that seismic waves excited by the surf, together with the effect of the Earth’s tides on the subsoil, can be used to better understand the properties of the Earth without having to drill into the ground. Knowledge of subsurface stress or strain fluctuations is important for safety in construction and mining, and monitoring geological processes in volcanoes and fault zones, for example.
Source: Science Daily