Another strange Hawaiian volcano is blasting out "ballistic blocks" the size of kitchen appliances and the authorities are warning it could get worse.

Since a new zone of Mount Kilauea began erupting almost two weeks ago, lava has wrecked dozens of homes and forced hundreds of people to be evacuated.

An ash plume rising up to two miles (more than 3,000m) prompted officials to warn pilots to avoid the area.

Quakes as strong as magnitude 4.4 have been felt on the largest island.

The floor of the volcano's caldera (the bowl where lava erupts) is deflating, causing stress at the volcano's base.

This is causing earthquakes and new fissures to open in the ground, and creating the risk of new, highly explosive steam-powered eruptions as the magma meets underground water.

Boulders of up to 2ft (60cm) were found a few hundred yards from the crater, reported the US Geological Survey's Hawaiian Volcano Observatory.

"During steam-driven explosions, ballistic blocks up to 2m (yards) across could be thrown in all directions to a distance of 1 km (0.6 miles) or more," it said.

"These blocks could weigh a few kilograms (pounds) to several tons. Smaller (pebble-size) rocks could be sent several kilometres... mostly in a downwind direction."