lava lake Kilauea
The lava lake at Outlook crater has now overflown says volcanologist. USGS

A lava lake at Hawaii's Kilauea volcano has risen and now appears to be spilling out of the Overlook crater.

The lava is overflowing onto the floor of the Halema'uma'u Crater. Thermal images from a webcam show how the lava is spilling out, with the red and yellow parts showing the hottest areas, volcanologist Rebecca Williams told IBTimes UK.

The darker blue areas are cold and the magenta parts show where the laver is overflowing – it is cooler because it is thinner and flowing over the colder rock below, she added.

The lava lake rose to its highest level several days ago and has been dangerously close to overflowing for a while. The molten pool first appeared in 2010 and normally is about 100ft below the rim of the Overlook crater. The USGS has yet to confirm it is overflowing.

However, earlier in April, it rose to just a few feet below the edge and authorities closed of the area to tourists. Yesterday, the US Geological Survey (USGS) released footage showing an explosion at the lava lake, where part of the crater wall collapsed.

"This happens because lava is full of gas. That gas can bubble out at the surface gently, or sometimes, builds up and spurts out, causing the splatter that we've been seeing at the lava lake," Williams said.

"The rockfall triggered a sudden, violent release of gas, causing the explosion. This sprayed liquid lava around the Halema'uma'u Crater rim [think of how if you cause a coke bottle to fizz over, it brings up coke liquid as well as the gas contained in the coke].

"This is a particularly interesting event because the volcanoes in Hawaii are often thought to be gentle, and indeed, are big tourist attractions where people can get quite close up to the activity. But they are capable of explosions, as seen today, and you certainly wouldn't want to get hit by a chunk of molten lava which is why the area around the crater is currently closed to visitors."

A report on the status of the lava lake from 28 April said the lava lake had dropped from about 7ft a day earlier to about 10ft. However, a statement said: "The lava lake reached briefly to the rim this morning, during a period when all spattering stopped, but did not get quite high enough to overflow on to the Halemaʻumaʻu Crater floor."

outlook crater hawaii
The lava lake within Halemaʻumaʻu Crater at the summit of Kīlauea on February 1, 2014. USGS

An eruption at Kilauea's summit has been ongoing since 2008 and after a small "throat clearing" explosion, the Overlook crater opened up. Lava was sometimes seen but was mostly masked by thick volcanic fume. However in February 2010, the lava rose and established a large lake that has been there ever since.

Explaining why the lava lake has risen, Williams said it is to with cycles of the magma chamber. She said: "Currently, it's the highest it's been during this eruption. There has been a lava lake at Kilauea's summit before.

"From 1823 to 1924 the Halema'uma'u Crater had a lava lake in it which even overflowed spreading lava across the floor of the Kilauea caldera. This current lava lake is in a crater inside Halema'uma'u, so is quite a bit smaller than that."