50 Fun Facts About Mauna Loa

What does the name Mauna Loa mean in Hawaiian?

Its neighbour Mauna Kea, the White Mountain, is only about 125 feet taller at the summit.

Mauna Loa is one of how many volcanoes that form the Island of Hawaii?

Kohala is the oldest and Kīlauea the youngest above water; Kamaʻehuakanaloa is still growing beneath the sea.

Mauna Loa holds which record among the world's volcanoes?

It was long thought the largest volcano of any kind until the submarine Tamu Massif was found to be bigger.

Which two volcanoes were ranked larger than Mauna Loa by 2020, pushing it to third?

Pūhāhonu is a mostly submerged shield in the Northwestern Hawaiian Islands; Tamu Massif lies 1,600 km east of Japan.

What shape of volcanic edifice is Mauna Loa, built by very fluid lava?

Its very fluid, silica-poor lava builds a broad dome whose slopes are only about 12 degrees at their steepest.

Measured from its base on the sea floor to its summit, roughly how tall is Mauna Loa?

That beats Everest's 8,848 metres, and the mountain's mass depresses the crust a further 8 km, so its true height is around 17,000 metres.

Roughly what fraction of the Island of Hawaii's surface area does Mauna Loa make up?

It covers 5,271 square kilometres and spans up to 120 km across.

What is the name of Mauna Loa's summit caldera?

It formed 1,000 to 1,500 years ago when a rift eruption drained a shallow magma chamber and the summit collapsed.

The summit caldera is named after what kind of creature?

The ʻāweoweo is a red bigeye whose colouring supposedly resembles the caldera's eruptive fires.

What supplies Mauna Loa's magma?

The Pacific Plate's drift will carry the volcano off the hotspot within 500,000 to a million years, and it will go extinct.

About how long has Mauna Loa been erupting?

It probably broke the ocean surface around 400,000 years ago; some dated rocks are 470,000 years old.

Which is the island's youngest volcano above sea level, often mistaken for a satellite of Mauna Loa?

Chemical analysis shows the two have separate magma chambers, though activity at one often coincides with quiet at the other.

How many times had Mauna Loa erupted from its first documented eruption in 1843 to 2025?

Historic eruptions typically begin with a curtain-of-fire fissure before concentrating at a single vent.

When did the first Mauna Loa eruption since 1984 take place?

It began at 11:30 pm on 27 November in the summit caldera and ended on 13 December.

How long was the record quiet spell that ended with the 2022 eruption?

Magma had been building beneath the volcano since 1984, and unrest was noted from 2019.

Which cross-island highway did the 2022 lava flows threaten but never reach?

The main flow front stalled about 1.7 miles short of it on 8 December before draining away.

How close did the 1984 lava flow come to the city of Hilo?

The glow lit the city at night, but two natural levees upstream broke and diverted the flow.

How long did the 1984 eruption last?

Tremor was so strong that the telescopes on Mauna Kea, 40 km away, could not be stabilised.

The 1950 eruption reached the ocean, 24 km away, in roughly how long?

It emitted 376 million cubic metres of lava in 23 days and permanently destroyed the village of Hoʻokena-mauka.

Which future general planned the 1935 bombing of Mauna Loa's lava to protect Hilo?

The observatory declared the bombing a success when the lava stopped a week later; volcanologists have disputed that ever since.

Why did the government gag the local press during the 1942 eruption?

It came four months after Pearl Harbor during a blackout; the Army Air Force then dropped sixteen bombs on the flows, to little effect.

The 1868 eruption coincided with the island's largest recorded earthquake; how many died?

The magnitude-eight quake triggered a landslide and tsunami in the Kaʻū district.

The 1872 to 1877 eruption was unusual for what reason?

It produced more than twice the lava of the 1950 eruption, but never threatened anyone.

Where did a strange one-day eruption of 1877 take place?

Onlookers in boats saw turbulent water and floating blocks of hardened lava within a mile of shore.

Which city is partly built on Mauna Loa lava flows from the 1880 to 1881 eruption?

At the time the settlement was a shoreside village further downhill and was unaffected.

Mauna Loa is one of the 16 sites on which watch-list drawn up by the IAVCEI?

The list identifies volcanoes worth special study for their destructive history and closeness to populated areas.

Who founded the Hawaiian Volcano Observatory in 1912?

He persuaded the Army to build a summit route in 1915, and declared Patton's 1935 bombing a success.

Which unit helped build the trail to the summit of Mauna Loa in 1915?

Many of the routes laid out then are still used by scientists today.

Who led the first recorded successful ascent to the summit in February 1794?

The botanist on Vancouver's expedition estimated its height at 4,156 metres with a barometer, remarkably close to today's 4,169.

Which Scottish botanist reached the summit in 1834 via the ʻAinapō Trail?

The man behind the Douglas fir stayed overnight to measure the caldera, though his figures proved wildly wrong.

What has been measured continuously at the Mauna Loa Observatory since March 1958?

The record, begun by Charles David Keeling of Scripps, is the famous Keeling Curve.

The graph of rising CO2 built from Mauna Loa readings is named after which scientist?

He supervised the programme until his death in 2005; the site was chosen for its remoteness and lack of vegetation.

Which milestone CO2 reading at Mauna Loa in 2015 was cited by Pope Francis in Laudate Deum?

The observatory has been part of NOAA's baseline network since 1972.

Besides the atmosphere, what else is observed from an observatory near Mauna Loa's summit?

The Mauna Loa Solar Observatory sits near the atmospheric station; the big telescopes are on neighbouring Mauna Kea.

Which protected area covers Mauna Loa's summit and parts of its flanks?

The park also takes in Kīlauea, a separate volcano to the east.

Which Hawaiian goddess of volcanoes and fire is associated with the island's eruptions?

She is called "the earth-eating woman" and, in legend, created the Hawaiian Islands.

What happened to Mauna Loa during the last ice age, 25,000 to 15,000 years ago?

Unlike Mauna Kea, it has since buried the glacial deposits under 150 to 300 metres of new lava.

Mauna Loa's slumping flank pushes Kīlauea eastward at roughly what rate?

The interaction has generated large earthquakes and a debris field off Kīlauea called the Hilina Slump.

A massive flank collapse 100,000 to 200,000 years ago formed which bay on Mauna Loa's west side?

Undersea surveys show such landslides caused megatsunamis, including a 325-metre wave on Lānaʻi.

What percentage of historical Mauna Loa eruptions began at the summit?

The northeast rift zone accounts for 31 percent and the southwest rift zone for 25 percent.

What did the 1926 eruption destroy near Hoʻōpūloa?

Together with 1950, it is one of two eruptions that wiped out villages, though no lives were lost.

What unusual cycle, unique among Hawaiian volcanoes, has Mauna Loa shown?

Two cycles of 1,500 to 2,000 years each have been identified in the radiocarbon record.

The 1975 lurch of the Hilina Slump caused a 7.2 earthquake and a tsunami that killed two people where?

The 14-metre wave struck campers on Kīlauea's coast.

The Hawaiian-Emperor seamount chain created by the hotspot stretches roughly how far?

It runs from Hawaii to the Kuril-Kamchatka Trench off Russia, built over about 70 million years.

What is Mauna Kea's claim over Mauna Loa?

Mauna Kea's peak at 4,207 metres is the highest point in Hawaii, though Mauna Loa is far bigger in volume.

How high above sea level does Mauna Loa's summit rise?

That is only slightly lower than neighbouring Mauna Kea, but Mauna Loa's bulk covers half the island.

Which US Navy lieutenant led the exploring expedition that climbed Mauna Loa in December 1840?

He hired around 200 porters in Hilo, and his summit party endured a snowstorm that collapsed their canvas roof.

In which year was the Mauna Loa Observatory founded as part of the US Weather Bureau?

It sits at 3,394 metres on the northern flank after earlier attempts to maintain a summit observatory failed.

On which flank zone of Mauna Loa did the fissures of the 2022 eruption open?

The 1984 eruption had also concentrated there; the tallest 2022 lava fountains reached 100 to 200 feet.

How did the 2022 eruption interrupt the CO2 readings behind the famous Keeling Curve?

Temporary solar power later let the observatory run at about a third of capacity while deposits still blocked the road.