Mauna Loa Trivia
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50 free Mauna Loa trivia questions with answers — geography quiz, new questions added Aug 2026.
Mauna Loa is the largest active volcano on Earth, and this quiz covers everything about the Long Mountain: how tall it really is from the sea floor, why its slopes are so gentle, the fish its caldera is named after, the 34 eruptions since 1843, the lava that nearly reached Hilo in 1984, the 2022 eruption that ended a 38-year silence, and the observatory on its flank where the modern record of carbon dioxide began. Easy questions ask which island it stands on and what kind of volcano it is; harder ones dig into George Patton's bombing plan of 1935, the wartime gag order of 1942, the botanist who first reached the summit in 1794 and the two undersea giants that have since bumped it down the size rankings. It suits geography and science quiz nights, Hawaii travellers and anyone who watched the 2022 eruption on the news. Every answer has been checked against the Wikipedia articles on Mauna Loa, its eruptions, its observatory and its neighbours, and each question shows its source once you have answered.
30 of 50 questions with answers and explanations. Play the quiz
Q 01What does the name Mauna Loa mean in Hawaiian?
Long Mountain
Long Mountain is apt: the volcano stretches about 120 km, from the island's southern tip across the summit to the coast near Hilo.
Q 02Mauna Loa is one of how many volcanoes that form the Island of Hawaii?
Five
Five volcanoes built the island, from oldest to youngest Kohala, Mauna Kea, Hualālai, Mauna Loa and Kīlauea; a sixth, Kamaʻehuakanaloa, is growing off the south-east coast but has yet to break the surface.
Q 03Mauna Loa holds which record among the world's volcanoes?
Largest active volcano by mass and volume
Largest active volcano by mass and volume is the title it keeps: bigger rivals mapped since, such as Pūhāhonu in the north-western Hawaiian chain, are ancient and long dead.
Q 04Mauna Loa is built almost entirely of which dark, iron-rich volcanic rock?
Basalt
Basalt lava is unusually runny, so Mauna Loa's eruptions mostly pour out as flows instead of exploding like volcanoes with stickier magma.
Q 05What shape of volcanic edifice is Mauna Loa, built by very fluid lava?
A shield
A shield volcano is built from thin sheets of runny lava that travel far before they harden, which is why Mauna Loa is so broad and its slopes so gentle.
Q 06Why does Mauna Loa's base lie 8 km below the sea floor?
Its weight sagged the crust
Its weight sagged the crust: the volcano's mass has pressed the sea floor into a deep bowl, so from true base to summit Mauna Loa stands about 17 km tall, nearly twice the height of Everest.
Q 07Roughly what share of the Island of Hawaii's land does Mauna Loa alone cover?
About 51 percent
About 51 percent of the island is Mauna Loa, which is why its lava can threaten opposite coasts: flows reached the sea on the west side in 1950 and came close to Hilo, on the east, in 1984.
Q 08What is the name of Mauna Loa's summit caldera?
Mokuʻāweoweo
Mokuʻāweoweo formed when the summit collapsed, and it is where Mauna Loa's eruptions typically begin before lava breaks out lower on the flanks.
Q 09Mauna Loa's summit caldera is named after what kind of creature?
A fish
A fish: a red Hawaiian bigeye whose colour is said to resemble the glow of the crater's eruptive fires.
Q 10What supplies Mauna Loa's magma?
The Hawaii hotspot
The Hawaii hotspot is a plume of hot rock rising from deep in the mantle; as the sea floor drifts across it, each volcano is eventually carried away from its magma supply and dies out.
Q 11For roughly how long is Mauna Loa thought to have been erupting?
About 700,000 years
About 700,000 years is the usual estimate: its first lavas erupted onto the sea floor between roughly 600,000 and a million years ago, so this giant is a geological youngster that had to grow extremely fast.
Q 12Kīlauea was long thought a mere satellite of Mauna Loa until lava chemistry showed the two have separate what?
Magma chambers
Magma chambers are separate for each volcano, yet when one is busy the other has often gone quiet: Kīlauea slept from 1934 to 1952 while Mauna Loa erupted repeatedly.
Q 13What are the lava fountains that open a Mauna Loa eruption called?
Curtain of fire
Q 21Why did the government gag the local press during Mauna Loa's 1942 eruption?
To deny Japanese bombers a beacon
To deny Japanese bombers a beacon: with Hawaii under nightly blackout months after Pearl Harbor, officials feared the lava's glow could guide warplanes in, so the eruption went unreported.
Q 22Which Hawaiian word do geologists use worldwide for rough, clinkery lava like Mauna Loa's 1984 flows?
ʻAʻā
ʻAʻā flows carry a jumble of sharp, broken clinker on top of a dense molten core, which makes them brutal to walk across; smooth, ropy lava goes by another Hawaiian name, pāhoehoe.
Q 23What made Mauna Loa's eruption of 1872 to 1877 unusual?
Curtain of fire: the fountains jet in a row from a crack that can run a kilometre or more, like a glowing drape, before the eruption settles on a single vent.
Q 14During Mauna Loa's 1984 eruption, what volcanic haze blanketed much of the state of Hawaii?
Vog
Vog, short for volcanic smog, forms when sulphur dioxide from the vents reacts with sunlight, oxygen and moisture; laze is a different hazard, made where lava pours into the sea.
Q 15Mauna Loa's 2022 awakening gave the Island of Hawaii its first what since 1984?
Dual eruption
Dual eruption: Kīlauea was already active next door, so the island had two volcanoes erupting at once. Both then went quiet within days of each other, a timing scientists called surprising and thought-provoking.
Q 16Which cross-island highway did Mauna Loa's 2022 lava flows threaten but never reach?
Saddle Road
Saddle Road, which crosses the high saddle between Mauna Loa and Mauna Kea, escaped when the main flow stalled about 1.7 miles short as its lava supply drained away.
Q 17What halted Mauna Loa's 1984 flow before it could reach Hilo?
Channel breaks diverted the lava
Channel breaks diverted the lava: natural levees upslope gave way and fed new side flows, so the tongue aimed at Hilo stagnated, and the eruption ended on 15 April.
Q 18What caused the loud explosions as Mauna Loa's 1984 lava crossed forest above Hilo?
Methane from scorched plants
Methane from scorched plants: lava cooks the vegetation it buries, and the gas seeps into hollows underground and explodes. In 1984 the blasts could be heard down in Hilo.
Q 19Mauna Loa's 1950 eruption sent lava to the ocean, 24 km away, in roughly how long?
About three hours
About three hours was all it took: the lava cut the coast highway and swept through Hoʻokena-mauka, yet everyone in its path got out unharmed before it hit the sea in towering clouds of steam.
Q 20Which future general planned the 1935 bombing of Mauna Loa's lava to protect Hilo?
George S. Patton
George S. Patton, then a lieutenant colonel in Hawaii, oversaw the Army raid of 27 December 1935; the lava stopped six days later, but whether the bombs deserve the credit is still disputed.
It never left the summit
It never left the summit: lava welled up in the caldera almost continuously for about 1,200 days, one of Hawaii's longest recorded eruptions, yet none of it threatened the towns below.
Q 24Where did Mauna Loa's one-day eruption of 1877 break out?
Underwater, just off the coast
Underwater, just off the coast: people on the water saw the sea churning as if boiling and blocks of hot lava bobbing to the surface within a mile of the shore.
Q 25The Hawaiian snack brand that shares Mauna Loa's name is best known for which product?
Macadamia nuts
Macadamia nuts are the Mauna Loa brand's business: it took the volcano's name because its first orchards were planted beneath the mountain in 1946.
Q 26Mauna Loa is one of 16 volcanoes on which watch-list drawn up by international volcanologists?
Decade Volcanoes
Decade Volcanoes were chosen in the 1990s, the UN's decade for disaster reduction, hence the name; each has a record of large eruptions close to where many people live.
Q 27Who founded the Hawaiian Volcano Observatory, which has monitored Mauna Loa since 1912?
Thomas A. Jaggar
Thomas A. Jaggar directed the observatory until 1940, and it was he who urged the Army to bomb the lava creeping toward Hilo in 1935, then declared the raid a success.
Q 28Which Army unit helped build the trail to Mauna Loa's summit in 1915?
The Buffalo Soldiers
The Buffalo Soldiers of the 25th Infantry, an African American regiment posted in Hawaii, cut the trail in 1915 so scientists could reach the summit; today's Mauna Loa Trail grew out of it.
Q 29Who led the first recorded ascent to Mauna Loa's summit in February 1794?
Archibald Menzies
Archibald Menzies, botanist on the Vancouver expedition, reached the top on his third attempt and measured its height with a portable barometer, coming remarkably close to the modern figure.
Q 30Which Scottish botanist climbed to Mauna Loa's summit in January 1834?
David Douglas
David Douglas, the man behind the Douglas fir, spent a night at the top taking measurements; a few months later he was found dead in a pit trap for wild cattle on Mauna Kea.