The USGS shared this incredible image on Twitter as a throwback to an amazing sight in 1969. The photo was originally taken Oct. 11, 1969 in Hawaii. The lava that formed this dome originated at the Kilauea Volcano, one of the most active volcanoes on Earth, according to the Hawaii Center for Volcanology. It has been in an almost constant state of eruption since 1983.
Lava domes form when thick magma bubbles to the surface and piles up around the vent, according to research from Oregon State University. There isn't enough pressure to cause a violent eruption, so it piles up instead.
Lava domes can grow as tall as 1,600 feet tall, but usually swell to about 30 to 320 feet, the USGS said.