The world's largest active volcano is erupting in Hawaii for the first time in 38 years.
Mauna Loa on Hawaii's Big Island began erupting at 11:30 p.m. local time on Nov. 27, a month after warnings by officials that it may become active again for the first time since 1984.
The eruption from the 13,681-foot volcano began in the summit caldera of Moku‘āweoweo inside Hawai‘i Volcanoes National Park, according to a news release by the United States Geological Survey.
The lava flows are contained within the summit and are not threatening communities located downslope from the volcano, according to the USGS. However, the organization upgraded the alert level from an advisory to a warning.
Nearby residents have been instructed to "review preparedness" for further guidance because "the early stages of a Mauna Loa eruption can be very dynamic and the location and advance of lava flows can change rapidly," per the USGS.
The organization warned that if the lava flows outside the walls in Moku‘āweoweo, it can "move rapidly downslope." The USGS also noted that the wind could carry volcanic gas, fine ash and a type of thin glass fibers known as as "Pele's hair" from the eruption.
A satellite view tweeted by USGS on the morning of Nov. 28 shows the lava being contained to the caldera.
Hawaii's civil defense agency held island-wide meetings last month to help residents prepare for possible evacuation in the case of an eruption. Experts say it would take just a few hours for lava to reach the homes nearest to vents on the volcano, according to The Associated Press.
Mauna Loa is one of six active volcanoes located in Hawaii. A volcano is considered active if it has erupted in the past 10,000 years, according to the USGS.
The volcano takes up more than half the surface area of Hawaii's Big Island and has erupted roughly once every six years for the past 3,000 years, according to the USGS. It has erupted 33 times since 1843, with half of the eruptions being contained to the summit area.
The 1984 eruption lasted for three weeks and came within four miles of Hilo, which has an international airport and a population of more than 45,000 people, per the USGS.
A 2018 eruption at the nearby Kilauea volcano caused widespread destruction of 700 homes.