Some volcanoes ‘scream’ at ever-higher pitches before they erupt.
The noise is created by a tremor caused by a swarm of mini earthquakes that precedes the eruption.
Scientists analysed an eruption sequence at Alaska’s Redoubt Volcano and found what they describe as audible ‘screams’ that followed seismic activity as the changed from steady pulses to rapid tremors.
Listen to it here:
Here is the processes that lead to volcanic eruption and volcanic screaming:
- Swarms of small earthquakes precede eruptions
- The frequency of the earthquakes increases
- They reach a point of such rapid succession that they create a harmonic tremor
- The frequency of the harmonic tremor steadily rises
- The volcano ‘screams’ due to incredible pressure building up
- The tremor and the screaming stops
- The volcano erupts
So a rise in the frequency of earthquakes could predict volcanic eruptions.