Sangumburi: The Crater Said to Have Formed Without a Drop of Lava
Hi everyone, it's GYULI, the tangerine sprite who's called Jeju's oreum home for a hundred years. Today I want to talk about Sangumburi, over in Jocheon-eup on Jeju. It's not as famous as Seongsan Ilchulbong or Hallasan, but people who really know Jeju tend to bring its name up sooner or later. Ask what actually makes it special, though, and surprisingly few people can say for sure. I used to think of it as just a big hollow on some oreum, but it turns out there's a much more interesting story behind it. Let's go through it together today — nothing too complicated, so just follow along.
A volcano without lava?
Sangumburi is known as a volcanic landform located in Jocheon-eup, on Jeju. Jeju has countless oreum, big and small volcanic cones, but Sangumburi is said to have formed in a somewhat different way from most of them. When people picture a volcano, they usually imagine lava piling up into a peak — but Sangumburi is said to have taken shape differently from that.
According to the accounts passed down, Sangumburi is thought to have formed when magma met underground water, triggering a powerful explosion that caused the ground to cave in, rather than lava piling upward into a cone. That's said to be the unusual part — the land sank inward from the force of an explosion instead of rising from accumulated lava. This kind of landform is sometimes called a maar-type crater, something Jeju apparently doesn't have many examples of. Exactly when or how large the explosion was isn't something I can state definitively — different sources describe it a little differently, so it's probably best treated as generally understood rather than settled fact.
No peak at all — just a hollow cut into flat ground
A lot of people say Sangumburi feels surprising the first time they actually see it. You'd normally expect a volcano to rise into a peak visible from a distance, but Sangumburi reportedly has no real peak to speak of. Some describe it as walking across flat land and suddenly coming across a huge hollow sunken into the ground. Having a hollow instead of a peak as its defining feature can feel a little unfamiliar to first-time visitors, I'd imagine.
This unusual shape is said to have stirred people's curiosity about Sangumburi for a long time — why this spot caved in the way it did, and how it differs from Jeju's other oreum. But it's hard to say every detail of its formation and timing has been definitively worked out, so I'll stick to phrases like 'said to be' and 'reportedly' here too. I'd rather leave room for uncertainty than state something confidently and get it wrong later.
Rather than building a peak, it's said to have formed by the ground caving in — and that might be exactly what makes Sangumburi feel like Sangumburi.
— 🍊 GYULIThe hillside said to turn silver with grass each autumn
A lot of people associate Sangumburi with its silver grass. The slopes around the crater are said to be especially known for turning into a sea of silver grass. Come autumn, people reportedly make a special trip just to see the silvery grass rippling across the hillside. Some describe the way it bends and rises with the wind as looking almost like waves.
That said, exactly when the silver grass hits its peak is said to vary a bit from year to year, so I can't pin it down to specific dates. Autumn is generally known as the best season to catch it, but the timing can shift a little earlier or later depending on that year's weather, so if you're planning a visit, it's worth checking closer to the date. I wish I could give you an exact date every time, but that part is really up to nature, not me.
Looking back over everything, Sangumburi isn't the flashiest spot on Jeju, but it does seem to carry a story worth knowing. The unusual way it's said to have formed through explosion rather than lava, and the way it shows a different face each season, both make it kind of compelling. Next time you're planning a Jeju itinerary, it might be worth tucking Sangumburi in among the more famous stops. As they say, you see more once you know more — keep today's story in mind and the view might land a little differently.
GYULI's Tip · Sangumburi is said to draw the most visitors in autumn when the silver grass is around, so it's worth checking that year's grass conditions and opening hours before you go.