Mauna Loa, the world's largest active volcano, began to erupt on Sunday. Nearby, Kilauea, another volcano on Hawaii island, is also erupting. It was Mauna Loa's first eruption since 1984, said the U.S. Geological Survey, noting the volcano alert level for Mauna Loa has risen to Warning/Red.
The enormous volcano, which covers half of Hawaii Island, is among Earth's most active volcanoes, having erupted 33 times since its first well-documented historical eruption in 1843, according to the Hawaiian Volcano Observatory (HVO).
"The Northeast Rift Zone eruption of Mauna Loa continues, with several fissures and lava flows active. Several lava flows are traveling in a northeast direction," said HVO on Wednesday morning, adding that the longest and largest lava flow had crossed the Mauna Loa Weather Observatory Road.
Hawaii Emergency Management Agency tweeted Wednesday that there is "still no immediate threat to populated areas from Mauna Loa eruption," as the lava was still about 5.6 km from Daniel K. Inouye Highway and "moving very slowly."
However, citing Ken Hon, HVO scientist-in-charge, local media reported a "very high probability" that lava from the eruption will reach the highway, eventually closing a key thoroughfare across Hawaii Island.
If the lava does cut through the highway, it would significantly impact the island's infrastructure, the news outlet reported, adding that Hawaii Island Mayor Mitch Roth is asking residents to consider alternative routes.
Kilauea volcano, the youngest and southeasternmost volcano on the island located some 40 km east of Mauna Loa, has been erupting since Sept. 2021. Since 1952, Kilauea has erupted dozens of times. From 1983 to 2018, its eruptive activity was nearly continuous along the volcano's east rift zone.
A summit eruption that began within Halema'uma'u Crater in September 2021 is ongoing, according to the HVO. Hawaii Governor David Ige on Tuesday signed an emergency proclamation related to the eruption of Mauna Loa but noted in a tweet that Hawaii Island is still open to visitors, "and it is safe to view the volcano from a distance."
The Hawaii Volcanoes National Park remains open, with some road and hiking trails closed due to volcanic hazards. The park pointed out that the new eruption "is expected to draw an influx of visitors who hope to see a rare dual eruption from both Kilauea and Mauna Loa volcanoes."
Park officials said neither eruption is currently threatening homes or infrastructure and urged visitors to check the park website for closure updates, safety alerts, air quality and other information, including links to HVO webcams and eruption updates.