Rumble. Rumble.

When will the kaboom come?

The ground shakes and swells at Mauna Loa, the largest active volcano in the world. The mountain could erupt.

But when?

Scientists don’t expect the eruption right away. Still, officials on the Big Island of Hawaii send warnings: Be prepared.

Mauna Loa is one of five volcanoes that make up the Big Island of Hawaii. It’s not the tallest volcano. Mauna Kea is. But it is the largest. Mauna Loa takes up about half the island! The famous volcano hasn’t erupted for 38 years. But it has blown its top 33 times since 1843.

Cattle ranchers, coffee farmers, and beach resort workers live nearby. They know that if Mauna Loa does blow, lava could flow down its steep sides fast. Its enormous size may mean it holds more magma (underground lava). It could erupt from the top or from a lower opening called a vent. Once it starts, lava could reach farms in homes within days . . . or within hours.

Hawaii’s volcanoes are called shield volcanoes. Over the years, lava flows hardened into broad mountains. These volcanoes may remind you of the shape of a warrior’s shield.

For now, scientists watch. They take measurements. They guess how much magma has gathered underground. They check: Is the ground tilting? Swelling? Deflating? Any of these quick changes can mean kaboom is on the way.

Well, “kaboom” isn’t exactly right. Shield volcanos are dangerous. But they’re not as explosive as composite volcanoes. Learn about the three volcano types in Jet Balloon.

And the mountains will melt under Him, and the valleys will split open, like wax before the fire, like waters poured down a steep place. — Micah 1:4