Listen to Earthquakes

Seismometers record vibrations from a wide assortment of ground motion events. Each event type has a distinctive ground-motion signal with unique frequency and amplitude—its own seismic signature. Seismologists are trained to identify the source of seismic events seen on a webicorder based on its ‘seismic signature’. Although most ground vibrations have a frequency too low for human hearing, we can speed up the signal and make it audible. Listen to the sound of an earthquake and match it with the event that created it using the spectrogram/seismogram to help. Is the sound from:

• The 2001 Nisqually earthquake recorded in Sequim, Washington?
• A rock avalanche at Mount Rainier?
• Lava spine extrusion at Mount St. Helens?
• An eruption, gliding tremor and explosion at Mount Redoubt, Alaska?