Earth's Free Oscillations
Audiovisual demonstration where traveling waves are generated by the sum of many standing waves (normal modes) at the Earth’s surface.
VIDEO: shows 9 of Earth’s observable lowest frequency normal modes (color rings) with tones corresponding to the center frequency of each mode. Higher frequency modes are represented by cool colors and low frequencies by warm colors. The outer ring (white) represents the sum of the colored rings. Can you spot the waves traveling through the ring?
AUDIO: The loudness of each tone is modulated by its amplitude envelope. Notice how the chord evolves over time as the higher frequencies die away.
