Hawaii's continuously erupting Kīlauea has been pretty busy this week, creating short-lived islands and hurling lava bombs at unsuspecting tourists over the last few days.

On Monday morning, a lava bomb (a flying chunk of molten rock) hit a tour boat, injuring 23 people, and damaging the boat roof and railing.

According to officials, 13 passengers are being treated at the hospital, and 10 passengers with more minor injuries were treated on arrival in Wailoa Harbor.

"Of the injured, four were taken by ambulance, one seriously injured with a fractured femur," Hawaii County officials said in a statement.

If tourists keep getting too close, this may not be a one-off event. There are a number of areas where volcanic material is entering the ocean, and when this happens, the cold water can cause an explosion, fragmenting the lava.

But these lava bombs aren't the only thing Kīlauea has been creating on Hawaii's Big Island.

On Friday morning, a Hawaiian Volcano Observatory crew noticed that a tiny little island had formed just a few metres off the coast.

It was still very fresh, approximately 20-30 feet (6-9 metres) in diameter, and was oozing lava and steam.

Although you might not think that a tiny lava pile so close to the mainland would count as an island, the definition used is a piece of land surrounded by water, and so this little guy fits the bill.

That was until a few days later when the island joined up with the Big Island, making it an isthmus.

But it was fun while it lasted, and Kīlauea is not looking like it's going to be stopping any time soon.

We'd just recommend staying away from the water and any potential lava bombs.