Earthquake
Modern seismometer If you speeded up any earthquake signal and listened to it with a hi fi, it would sound like thunder. east-west north-south up-down.
Locating Earthquakes. Solid Inner Core Fluid Outer Core → magnetic field! Flexible Mantle Brittle Crust What's inside the Earth...
Gravimeters for seismological broadband monitoring: Earth’s free oscillations Michel Van Camp Royal Observatory of Belgium.
