Volcano Watch: Kamaʻehuakanaloa — the volcano formerly known as Loʻihi Seamount

USGS map Earthquakes detected by HVO’s seismic network in December 2021, with the size of the circles corresponding the earthquake magnitude and the color corresponding to the earthquake depth. The cluster of mostly blue earthquakes are from a persistent swarm about 30 km (19 miles) underneath Pahala. Kamaʻehuakanaloa’s earthquake swarm was mostly 5–13 km (3–8 miles; yellow) below sea level, with a few shallower events.
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The USGS Hawaiian Volcano Observatory monitors 6 volcanoes: Kilauea (currently erupting within Halema‘uma‘u), Mauna Loa (most recent eruption in 1984), Hualalai (most recent eruption in 1801), Haleakala (on Maui; most recent eruption sometime between 1480 to 1600 AD), Maunakea (most recent eruption over 4,000 years ago), and Kama‘ehuakanaloa (most recent activity in 1996).

This last volcano may seem unfamiliar, perhaps because its name was recently updated: in July 2021, Lo‘ihi Seamount was renamed Kama‘ehuakanaloa by the Hawaii Board on Geographic Names.

The former name was introduced in 1955 by Dr. Kenneth O. Emery, following a 4-day bathymetric (sea-floor topography) survey in 1954 off the south coast of the Island of Hawaii. The survey was done at the request of the Office of Naval Research and five seamounts were identified.

Dr. Emery, a professor at the University of Southern California, asked Mary Kawena Pukui and Martha Hohu (both Bishop Museum staff), and Dr. Gordon A. Macdonald (HVO director) to name the seamounts. They selected names based on a short physical description. For the seamount located about 30 miles (19 km) south of the Kilauea coastline and rising to 3,189 ft (975 m) below sea level, the name Lo‘ihi was assigned, meaning long; indeed, this seamount is longer than its neighbors.

At the time, Dr. Emery speculated that: “There is a high degree of probability that the seamounts are of volcanic origin, and correspondingly that the differences which exist may be indications of the nature of the early stages of a volcano forming well below sea level. If this conclusion is correct then the two shallowest seamounts (Papa’u and Loihi) must be considered parasitic (in the sense of topography not activity) volcanoes on the flank of Kilauea …”

In other words, Dr. Emery interpreted “Loihi” to be a volcanic cone erupted by Kilauea. However, the seamount was recognized to be an active submarine volcano, and the youngest volcano in the long line of the Hawaiian-Emperor chain, because of earthquake swarms in the 1970s. Kama‘ehuakanaloa’s most recent eruption is thought to have been in 1996, when HVO detected 4,377 earthquakes between mid-July and mid-August. Recent oceanographic surveys have also determined that Papa’u is an uplifted fault block on the margin of the Hilina slump, not a volcano.

Kama‘ehuakanaloa’s previous name was descriptive but failed to reflect Hawaiian cultural knowledge. Several mele (chants), orally passed down and documented in writing decades before the 1954 expedition, describe Kama‘ehuakanaloa, an undersea volcano. As explained by Ku‘ulei Kanahele of the Edith Kanaka‘ole Foundation, Kama‘ehuakanaloa “is a powerful name that invokes the name of Pelehonuamea and her birth out of Kanaloa [the ocean].” The new name was unanimously adopted in July 2021 by the Hawaii Board on Geographic Names.

The recent violent explosive activity at Hunga Tonga-Hunga Ha’apai volcano, in the South Pacific, has some residents wondering if Kama‘ehuakanaloa has a potential for similar eruptions. We expect that as Hawaiian volcanoes near the surface and emerge, explosive interactions with ocean water may occur, but Kama‘ehuakanaloa is currently too deep underwater. Additionally, because Hawaiian volcanoes have more fluid magma than Hunga Tonga-Hunga Ha’apai, we expect smaller eruptions than the Jan. 14 Hunga Tonga-Hunga Ha’apai catastrophic blast.

It will be a millennia before Kama‘ehuakanaloa emerges from Moananuiakea (the Pacific Ocean). The volcano does make its presence known with earthquakes that are occasionally felt on Island of Hawaii, though.

Most recently, just before Christmas in the early morning of Dec. 24, a magnitude 4.9 earthquake under Kama‘ehuakanaloa caused weak to light shaking felt by at least 29 people from Naalehu to as far north as Kailua-Kona and Honomu. In the 2 weeks leading up to this earthquake, over 50 smaller earthquakes had been detected by HVO’s earthquake-monitoring network.

Kama‘ehuakanaloa may be out of sight, but it is not out of mind. It is honored in mele and though it remains under the ocean surface, it continues to occasionally remind us of its presence with earthquakes we can feel on land. In thousands of generations, perhaps our descendants will witness Kama‘ehuakanaloa, the “reddish child of Kanaloa,” finally emerging and forming a new island.

Volcano activity updates

The Kilauea volcano eruption has paused. Its USGS Volcano Alert level is at WATCH (https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels). Kilauea updates are issued daily.

Lava returned to the western vent within Halema‘uma‘u crater at about 5:52 a.m. HST on Tuesday, following a pause lasting about two days. It paused again around midnight Friday. All lava has been confined within Halema‘uma‘u crater in Hawaii Volcanoes National Park. Sulfur dioxide emission rates remain elevated and were measured at approximately 2,800 tonnes per day on Tuesday. Seismicity is elevated but stable, with few earthquakes and ongoing volcanic tremor. Summit tiltmeters show several deflation and inflation patterns over the past week. For more information on the current eruption of Kilauea, see https://www.usgs.gov/volcanoes/Kilauea/recent-eruption.

Mauna Loa is not erupting and remains at Volcano Alert Level ADVISORY. This alert level does not mean that an eruption is imminent or that progression to an eruption from the current level of unrest is certain. Mauna Loa updates are issued weekly.

This past week, about 77 small-magnitude earthquakes were recorded below the summit and upper elevation flanks of Mauna Loa — the majority of these occurred at shallow depths less than 10 kilometers (6 miles) below sea level. Global Positioning System measurements show low rates of ground deformation over the past week. Gas concentrations and fumarole temperatures at both the summit and at Sulphur Cone on the Southwest Rift Zone remain stable. Webcams show no changes to the landscape. For more information on current monitoring of Mauna Loa, see: https://www.usgs.gov/volcanoes/mauna-loa/monitoring.

Ten earthquakes were reported felt in the Hawaiian Islands during the past week. Listed here are felt events with magnitudes above 3: a M3.6 earthquake 8 km (4 mi) E of Pahala at 34 km (21 mi) depth on Jan. 26 at 1:38 a.m. HST, a M4.7 earthquake 10 km (6 mi) NNE of Wailua at 41 km (25 mi) depth on Jan. 25 at 12:51 a.m. HST, and a M3.0 earthquake 9 km (5 mi) ENE of Pahala at 32 km (20 mi) depth on Jan. 24 at 11:58 a.m. HST.

Please visit HVO’s website for past Volcano Watch articles, Kilauea and Mauna Loa updates, volcano photos, maps, recent earthquake info, and more. Email questions to askHVO@usgs.gov.

Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates.