The eruption of the Hunga Tonga volcano and its blast wave around the globe

Posted on 16. January 2022

On the 14 January in 2022, a large eruption of the Hunga Tonga-Hunga Haʻapai volcano began at 04:14 UTC. The eruption was so loud that it could be heard not only in Fiji which is 750 km away, but also at Alaska which is more than 9.300 km away.

Until now, the third explosion of the Krakatoa eruption in 1883 has been reported as the loudest sound heard in historic times. It was heard on the Indian Ocean island of Rodrigues near Mauritius, 4.800 km away. It seems like this record was broken.

At Germany, we didn't hear anything - but the blast wave which has traveled around the whole globe was measurable.

hunga-tonga-volcano-blast-wave-pressure-measurement

The first blast wave from the north (1) has been peaked on the 14. January at 19:34 UTC at Neckarsulm Germany which is 16.880 km away from Tonga. It took the blast wave 15 hours and 20 minutes to reach Neckarsulm. The blast wave has traveled with an average speed of 305,8 m/s.

The wave (2) which traveled around the other side of the globe has arrived on the 15. January at 01:35 UTC from the south (Hello Flat Earth Society).

After about 35 hours and 30 minutes later on the 16. January at 07:00 UTC, the wave from the north has passed Neckarsulm (3) a second time when it has covered another 40.075 km around the globe.

hunga-tonga-volcano-blast-wave-pressure-measurement-third-round-trip

On the 18 January, the first blast wave has passed Neckarsulm a third time (4) at around 19:00 UTC after another round trip.

Could you feel the pressure change?

No. The pressure change had an amplitude of about ~1,4 hPa. Under 800m above seelevel, 8,7m elevation is equivalent in 1 hPa.

Our local newspaper Stimme picked up the news.

How did you capture the data?

The pressure change by the blast wave has been captured by my cheap weather station (WH3000SE) which sends the data to my Home Assistant installation.

Even smartwatches have captured the pressure change.

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