​Cleveland Volcano Eruption First Detected By Using Infrasound​​

May 6, 2021

The Cleveland volcano aviation alert went to Orange after a sequence of explosive eruptions were detected in Alaska. At first, there has been no visual confirmation as seeing conditions didn’t allow for direct observation.

Cleveland Volcano Eruption

However, the Alaska Volcano Observatory used infrasound at a very low frequency, typically less than 20 hertz, during their detection.

This is well below anything a person can hear and are generated by magma motion and explosions during an eruption. Infrasound detectors can “hear” these sounds from thousands of kilometers away due to the ability of infrasound to travel easily through water, land and air, so they can propagate around the globe. Infrasound has been used numerous times to detect both near and far eruptions from Fairbanks, Alaska, where a number of infrasound receivers are located.

Although infrasound technology has been around for decades, only recently has it been brought in as a key piece of volcano monitoring, as it can detect explosions like what occurred at Cleveland when both visibility is poor and seismometer coverage isn’t available.

The second explosion detected by infrasound was spotted by a satellite photo, which captured a small plume reaching 15,000 feet and elevated summit temperatures.

This activity seems to have become more continuous, with the seismic station at Okmok, 120 kilometers away, recording some of the tremor.

However, by Sunday, the tremors seem to have subsided to some degree, suggesting the eruption might be waning.

This Cleveland eruption might be a dome collapse followed by sub-plinian explosions caused by the rapid release of pressure on the underlying volcano magma below the summit.