Tonga volcano sent shock waves right through Jacksonville

This is how it became so explosive

Satellite showing abrupt shock wave propagating radially outward in all directions from the volcanic clouds of Hunga Tonga on 15 January 2022.

The tiny Kingdom of Tonga experienced a massive underwater volcano eruption that sent a shock wave through Jacksonville and around the world twice.

The crescent-shaped area of “bow shock wave” ripples persisted, due to the robust and dense volcanic cloud acting as an obstacle to the easterly winds within the stratosphere. (CMISS)

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The Hunga-Tonga-Hunga-Ha’apai volcano has blown several times in the past including as recently as 2015 but scientists say this is its largest eruption.  Volcanologists are scrutinizing the January 15 eruption for possibly being the highest volcanic cloud since the 1991 eruption of Mount Pinatubo in the Philippines.

3D seafloor image of submarine volcanic eruptions around Tonga since 2000. Volcanic activity is not uncommon but the recent eruption was much bigger than any historic event in the region.

How does a volcano get so explosive when it is underwater?

Even when temperatures are hotter than 2000°F water can cool down hot magma when it trickles out from a volcano. This is often the result in volcanoes around Hawaii and Iceland which contain basaltic magma that is relatively low in viscosity and in gas content.

This is not the case with the Hunga-Tonga-Hunga-Ha’apai volcano. Since it blasted into the water rapidly,  hot magma in direct contact with cold water resulted in what scientists call “fuel-coolant interaction” which is just like a chemical explosion jetting out volcanic particles at supersonic speeds.

Further turbocharging the explosive power, this type of volcano involves more viscous magma with a higher gas content. That power pushed the ash plume extraordinarily high with a 160 mile wide diameter.

Volcanologists can’t determine if all the pressure has been released to limit additional volcanic threats.


About the Author:

After covering the weather from every corner of Florida and doing marine research in the Gulf, Mark Collins settled in Jacksonville to forecast weather for The First Coast.