Loʻihi

Loʻihi
Name	Loʻihi
Elevation	9750
Location	Pacific Ocean
Type	Seamount, submarine volcano
Age	Holocene
Last eruption	1996–1997

Loʻihi is a submarine volcano located southeast of the island of Hawaii (island), forming the youngest and most active submarine edifice in the Hawaiian–Emperor seamount chain. It represents a nascent shield volcano situated on the Pacific Plate and lies above the Hawaiian hotspot responsible for the emergence of Kilauea, Mauna Loa, Mauna Kea, Hualalai, and Kohala. Loʻihi’s study informs research on hotspot theory, plate tectonics, oceanography, marine geology, and volcanology.

Geography and Physical Characteristics

Loʻihi rises from the seafloor of the Pacific Ocean about 35 kilometers southeast of Pāhala, Hawaii and 20 miles from the Kīlauea caldera region, with its summit currently about 975 meters below sea level and its base on the Emperor Seamount Chain at roughly 11,000 meters depth. The edifice’s flanks display classic shield volcano slope morphology comparable to Mauna Loa and Mauna Kea, and bathymetric mapping by NOAA vessels, R/V Kilo Moana, R/V Thomas G. Thompson, and DSV Alvin has revealed rift zones, radial fissures, and pit craters analogous to features at Kīlauea and Piton de la Fournaise. Loʻihi’s coordinates and morphology have been refined by surveys from USGS Hawaiian Volcano Observatory, Woods Hole Oceanographic Institution, and the University of Hawaii at Manoa.

Geology and Formation

Loʻihi formed from submarine eruptions fed by mantle plumes associated with the Hawaiian hotspot beneath the Pacific Plate. Petrology studies of dredged and drilled basalts highlight tholeiitic and alkalic transitions similar to those recorded at Kohala and Mauna Kea, with geochemical signatures analyzed at laboratories such as Scripps Institution of Oceanography, Lamont–Doherty Earth Observatory, and University of Cambridge. Radiometric dating using techniques developed at California Institute of Technology and Massachusetts Institute of Technology places Loʻihi’s activity in the Holocene with episodic construction phases like those inferred for Kīlauea and Mauna Loa. Structural comparisons to Emperor Seamounts and mapping from NOAA Ship Okeanos Explorer link Loʻihi to mantle dynamics studied by researchers at Stanford University, University of Washington, and University of California, Santa Cruz.

Volcanic Activity and Monitoring

Historic and recent seismic swarms recorded by the Hawaiian Volcano Observatory, Pacific Tsunami Warning Center, and networks operated by IRIS and USGS indicate recurrent eruptive episodes, including documented unrest in 1996–1997 and seismicity in 2015 monitored by deployments from NOAA, NSF, and the Royal Society-affiliated teams. Monitoring employs hydrophones, ocean-bottom seismometers developed by WHOI, Lamont, and MBARI, remote sensing from Landsat, MODIS, and shipborne multibeam sonar by Kongsberg Maritime. Submersible work by DSV Alvin, ROV Jason, and the HOV Pisces has observed pillow lavas, fissure eruptions, and seafloor deformation, complementing geodetic methods adapted from GPS campaigns used around Hawaii Volcanoes National Park and terrestrial analogs such as Mount St. Helens.

Ecology and Hydrothermal Systems

Loʻihi hosts hydrothermal vent fields that sustain chemosynthetic communities dominated by thermophilic and barophilic organisms investigated by biologists from Monterey Bay Aquarium Research Institute, University of Hawaii at Manoa, Smithsonian Institution, and National Geographic Society. Vent fluids support microbial mats, tube worms, and unique arthropods similar in study to communities at East Pacific Rise, Mid-Atlantic Ridge, and Juan de Fuca Ridge. Microbial isolates from Loʻihi have been cultured and genetically characterized at Harvard University, Max Planck Institute for Marine Microbiology, and University of California, Berkeley revealing extremophiles with links to research at J. Craig Venter Institute and Lawrence Berkeley National Laboratory. Hydrothermal alteration has produced sulfide deposits investigated for mineralization parallels with Black Smoker systems and compared to deposits studied at Kermadec Arc and Izu–Bonin systems.

Human Interaction and Research

Scientific exploration of Loʻihi has involved collaborations among institutions including USGS, NOAA, NSF, University of Hawaii, WHOI, MBARI, Scripps Institution of Oceanography, and international partners such as National Oceanography Centre and Japan Agency for Marine-Earth Science and Technology. Research cruises using R/V Roger Revelle, R/V Melville, and R/V Kilo Moana have deployed submersibles and sampling gear; publications appear in journals like Science, Nature, Geology, and Journal of Geophysical Research. Outreach and policy intersections touch agencies including Hawaii Department of Land and Natural Resources and organizations like The Ocean Conservancy and Monterey Bay Aquarium, while museum exhibits have featured Loʻihi material at Smithsonian National Museum of Natural History and Bishop Museum.

Future Growth and Hazards

Continued volcanism could eventually raise Loʻihi above sea level to form a new island, a process analogous to the growth history of Kohala and Hualalai, but this would require sustained eruptive accumulation over tens to hundreds of thousands of years as modeled by researchers at Stanford University, University of Oxford, and Princeton University. Hazards include local seismicity, tsunamigenic flank collapse scenarios studied with numerical models from California Institute of Technology and Scripps Institution of Oceanography, and hydrothermal alteration that may weaken slopes as observed at Maule, Montserrat, and Montserrat eruption case studies used for comparison. Emergency response planning involves coordination among Hawaii Emergency Management Agency, Pacific Tsunami Warning Center, and international scientific advisory bodies.

Category:Submarine volcanoes Category:Volcanoes of Hawaii