Hawaii's Kilauea Volcano spewing 'ballistic blocks'

  • 17/05/2018

"Ballistic blocks" the size of microwave ovens are shooting from Hawaii's Kilauea volcano in what may be the start of explosive eruptions that could spew huge ash plumes and hurl smaller rocks for kilometres, the US Geological Survey says.

Such eruptions, last seen nearly a century ago, have been a looming threat since Kilauea, one of the world's most active volcanoes, erupted nearly two weeks ago.

Explosions in Kilauea's crater sparked an aviation red alert due to risks the ash plume could blow into aircraft routes and damage jet engines.

More explosions are expected and may be more powerful, the USGS warned. These steam-driven blasts could send a 6100-metre ash plume out of the crater, hurling 10-12 ton boulders up to 800m and scatter pebble-sized rocks over 20km, the USGS said.

This type of eruption has the potential to carpet the Big Island in much thicker ash than current dustings and possibly spread the powder and volcanic smog across the Hawaiian islands and farther afield if it enters the stratosphere.

"This morning dense ballistic blocks up to 60cm across were found in the parking lot a few hundred metres from Halemaumau (Kilauea's crater)," the USGS said in a statement. "These reflect the most energetic explosions yet observed and could reflect the onset of steam-driven explosive activity.

A 4.2 magnitude earthquake at the volcano prompted authorities to issue an alert reassuring rattled Big Island residents that there was no risk of a tsunami from the volcanic activity.

In the community of Volcano, just north of Kilauea's crater, business was way down and people were on edge.

In just a few hours residents had been shaken by an earthquake, dusted with ash and for the first time since the start of the eruption smelled the rotten-egg stench of toxic sulfur-dioxide gas.

Smog from Kilauea drifted north up the island chain as the districts of Kau, Puna, and North and South Hilo were told by the National Weather Service to expect ashfall.

There was no effect on air carrier operations to Hawaii on Wednesday.

No serious injuries or deaths have been reported from the eruption.