Shock waves detected in Chicago after volcano eruption in Tonga

A volcanic eruption Saturday in the South Pacific island nation of Tonga was so powerful that its shock wave caused changes in air pressure detected thousands of miles away in Chicago.

A spike in air pressure readings was first detected at O’Hare Airport between 8:20 and 8:30 a.m. Saturday as the shock wave moved east from the volcano, according to the National Weather Service.

The other side of the shock wave, which moved west from the eruption, circled the globe before reaching the Chicago area early Sunday morning, caused more pressure fluctuations, the weather service said.

"The eruption was so powerful that the waves actually propagated all the way around the globe and then back again," meteorologist Gino Izzi said.

"The atmosphere acts and behaves like a fluid, so if you were to throw a big rock into a large pool you would see the ripples coming out around where the rock hit the water," Izzi added. "When the volcano erupted it was essentially the same thing. There was a massive disturbance that pushed air, just like a rock hitting the pool. The waves rippled out in every direction away from that volcano."


Izzi said he couldn’t remember the last time a volcanic explosion thousands of miles away was powerful enough to be felt in the Chicago area. "I think it’s been quite some time since we had one that strong," he said.

Satellite images showed the Saturday undersea eruption, with a plum of ash and steam rising above the water. New Zealand and Australia were able to send military surveillance flights to Tonga on Monday to assess the damage.

satellite image from Japan Meteorology Agency showing undersea volcanic eruption near Tonga

A British woman who was missing has been found dead, her family said, in the first reported fatality on Tonga.

A fiber-optic cable that connects the island nation to the rest of the world was likely severed in the explosion, leaving most 105,000 Tongans unable to use the internet or make phone calls abroad. It could take weeks to repair the severed cable.

Tsunami waves crashed into Tonga’s shoreline, damaging boats and shops. Two people in Peru drowned as the waves crossed the Pacific, also causing minor damage from New Zealand to Santa Cruz, California.