Volcanic Seamount Deep Beneath the Sea Off Hawaii Is Rumbling to Life

A volcanic seamount that lies deep beneath the sea off Hawaii is rumbling to life, according to authorities.

The Kamaʻehuakanaloa seamount is an active, underwater volcano that lies 22 miles off Hawaii's southeast coast. Its summit is about 3,200 feet below sea level. Seamounts are large landforms that rise from the ocean floor, but don't reach the surface of the water.

The Hawaiian Volcano Observatory recorded an increase in seismic activity rumbling from the volcano on July 16 at 2 a.m.

Just 24 hours later, two dozen earthquakes, with magnitudes between 1.8 to 3.0, were recorded from 1:30 a.m to 6 a.m, the observatory said in a statement.

A file photo of lava from the Kilauea volcano. The Kamaʻehuakanaloa seamount lies off the coast of the Volcanoes National Park. blagov58/Getty

The seismic tremors were measured by pulses of seismic energy every 15 to 20 seconds, the observatory said. The activity was ongoing when the statement was issued, and by that time 24 earthquakes had been recorded.

The Hawaiian Volcano Observatory also recorded no damage to nearby buildings. There was "no shaking" felt during the temblors.

The Kamaʻehuakanaloa seamount lies off the coast of the Volcanoes National park, the island containing Mauna Loa—the largest volcano on earth—and Kīlauea—one of the most dangerous volcanoes in the U.S.

Hawaiian Volcano Observatory Scientist-in-Charge Ken Hon said in the statement that the increased activity doesn't currently point to a potential eruption.

"This seismic activity is likely the result of magma movement beneath Kamaʻehuakanaloa seamount and currently shows no sign of leading to an eruption," Hon said. "If the swarm intensifies or changes significantly, [Hawaiian Volcano Observatory] will issue an additional notice. Because of the great depth of the volcano within the ocean and style of Hawaiian eruptions, an eruption of Kamaʻehuakanaloa would pose no threat to the Island of Hawaii. Neither Mauna Loa nor Kīlauea volcanoes show any change in activity associated with this earthquake swarm."

Earthquake activity from Kama'ehuakanaloa has been recorded since the early 1950s. The biggest earthquake event there occurred between July and August 1996.

During this time more than 4,000 earthquakes were recorded. Around 95 of those reached a magnitude between 4.0 and 4.9.

In 2020, 100 earthquakes were recorded at the seamount, nearly 20 at a magnitude of 3.0 to 3.9.

As the summit of the volcano lies thousands of feet below sea level, there are no monitoring instruments inside, however scientists can record its activity using seismometers on the land.