The world’s largest active volcano is erupting for the primary time in virtually 40 years. The Mauna Loa volcano, which is positioned on the Big Island in Hawaii, began erupting on Sunday evening, breaking its longest quiet streak in recorded historical past.

The U.S. Geological Survey mentioned in an advisory that the eruption started at 11:30 p.m. HST on Sunday in Moku‘āweoweo, the summit caldera of the volcano. The lava flows, the USGS said, were contained around the summit and were not currently posing a danger to communities down the slope of the volcano.

The National Weather Service in Honolulu issued an ash fall advisory through 6 a.m. HST (11 a.m. EST) Monday, warning that up to a quarter-inch of ash could fall on portions of the Big Island. According to Hawaii’s Emergency Management Agency, that advisory was prolonged early Monday morning to 10 a.m. HST (2 p.m. EST). Volcanic ash, which is made up of tiny particles of sand with notably sharp edges, could make air high quality harmful, even for individuals with out preexisting situations.

“People with respiratory illnesses should remain indoors to avoid inhaling the ash particles and anyone outside should cover their mouth and nose with a mask or cloth,” the NWS warned.

The USGS additionally warned that there’s an opportunity that lava flows might “move rapidly downslope” if the eruption spreads exterior the partitions of the caldera into areas the place the rock is cracked. Hawaii’s Emergency Management Agency said Monday morning it had acquired “some reports” of lava overflowing the caldera, however as of 5 a.m. HST (10 a.m. EST), USGS reported no threats to populated areas.

“Based on past events, the early stages of a Mauna Loa eruption can be very dynamic and the location and advance of lava flows can change rapidly,” the USGS mentioned in its assertion.

Mauna Loa towers over the opposite four major volcanoes on the Big Island: It stretches some 2.5 miles (4 kilometers) above sea degree and covers about half the realm of the island. The volcano final erupted in 1984, and lava flows from that eruption ultimately came to within 4 miles (6.4 kilometers) of Hilo, the largest metropolis on the island, touring 16 miles in simply 4 days. The volcano has erupted 33 instances for the reason that first eruption on document in 1843. Since 1868, flows of lava rock from these eruptions have reached the ocean eight instances. In 1950, the volcano skilled one in all its strongest eruptions on document, with some lava flows traveling the 15 miles (24 kilometers) between the vent and the ocean in simply three hours.