HAWAII Governor David Ige says US President Donald Trump has approved his request for a presidential disaster declaration for the Big Island as the state copes with Kilauea volcano’s eruption.

Gov. Ige’s office said the declaration means federal assistance will be available as the state covers costs associated with damaged roads, public parks, schools and water pipes.

It will also cover costs for geologists and security personnel at roadblocks.

The approval came a day after Gov. Ige requested the declaration.

Kilauea volcano began erupting lava into a residential neighbourhood on the Big Island on May 3.

It has destroyed 36 structures, including 26 homes.

Scientists believe the lava that’s been erupting in Hawaii since last week is magma that’s been stored in the ground since Kilauea volcano erupted in the same region 63 years ago.

Hawaiian Volcano Observatory Scientist Tina Neal said that an analysis of rock samples indicates the lava’s chemistry is similar to that from a 1955 eruption.

She says that’s why the lava has been cool and has been moving a little sluggishly.

Dr Neal says fresher, hotter lava could emerge because magma has been moving down Kilauea’s rift zone toward the area where the volcano is erupting.

She says hotter, fresher and gassier magma can result in more voluminous lava flows.

Fresher magma may also produce lava fountains that shoot higher into the air and larger, faster-moving lava flows.

Meanwhile, warnings that Hawaii’s Kilauea volcano could shoot boulders and ash out of its summit crater are prompting people to rethink their plans to visit the Big Island.

But most of the island is free of volcanic hazards, and local tourism officials hope travellers will recognise it’s ready to welcome them.

Rachel Smigelski-Theiss is among those who have shifted gears.

She had intended to visit Kilauea’s summit with her husband and 5-year-old daughter.

Now they’ve cancelled their trip.

Ms Smigelski-Theiss says she’s worried potential flight disruptions would strand them on the island.

Hawaii officials have had a busy month pleading with travellers to keep their plans even as they’re bombarded with images of natural disasters.

Last month it was floods on Kauai. Now it is lava from Kilauea volcano on the Big Island.