Thread by @Ecology4UPSC

Context: Mauna Loa, the world’s largest active volcano, starts to erupt in Hawaii.

Sunday’s eruption is the first one recorded since 1984. The previous eruption in 1984 sent lava flows within 5 miles of Hilo, the island's most populous town.

Mauna Loa shares the Big Island with Mauna Kea, which is the tallest mountain in the world when measured from its underwater base nearly 20,000ft below the ocean surface.

Mauna Loa is spewing sulfur dioxide and other volcanic gases. They form volcanic smog, or vog, when they mix with vapor, oxygen and dust in sunlight.

Mauna Loa:

1. It is one of five volcanoes that together make up the Big Island of Hawaii, which is the southernmost island in the Hawaiian archipelago. It is an active shield volcano with relatively gentle slopes.

2. It's not the tallest (that title goes to Mauna Kea) but it's the largest and makes up about half of the island's land mass.

3. It sits immediately north of Kilauea volcano, which is well-known for a 2018 eruption that destroyed 700 homes and sent rivers of lava spreading across farms and into the ocean.

4. Hawaii’s volcanoes are called shield volcanoes because successive lava flows over hundreds of thousands of years build broad mountains that resemble the shape of a warrior’s shield.

5. Lava eruptions from Mauna Loa are silica-poor and very fluid, and they tend to be non-explosive.

6. It is the largest subaerial and second largest overall volcano in the world (only after Tamu Massif).

Hazards are posed by Mauna Loa's eruption:

1. Lava: Molten rock could cover houses, farms or neighborhoods, depending on where it flows.

2. Volcanic gas: Mauna Loa is releasing volcanic gases, mostly sulfur dioxide.

The gases are present in their highest concentrations in the immediate area around the summit crater or vents. But they also combine with other particles to form vog

3. Vog: Vog can give healthy people burning eyes, headaches, and sore throats.

4. Glass particles: When hot lava erupts from a fissure and rapidly cools, it forms glass particles named “Pele's hair” and “Pele's tears” after the Hawaiian goddess of volcanoes.

#DidYouKnow? Scientists say all of Earth’s volcanoes combined emit less than one percent of the carbon dioxide that humans produce each year.