Murder on the Jogasaki Coast

-- Susan, every other Sunday

Last week I visited the Jogasaki Coast, a volcanic coastline on the east side of the Izu Peninsula. (About three hours from Tokyo by a combination of Shinkansen and local trains.)

The chariot awaits.

About 4,000 years ago Omuroyama (Mt. Omuro) erupted, sending a massive lava flow down the eastern side of the Izu Peninsula.

You can see the route of the lava flow in the jagged coastline.

The lava cooled as it reached the sea, but the flow was so massive that fingers of lava continued to push out into the ocean, creating raised cliffs and tentacular projections known as Igaigane.

Igaigane, with surf crashing beneath.

Surf crashes and swirls in the caves between the igaigane, sending spray more than twenty meters into the air. (And creating rainbows, as you can see if you look closely at the picture below.)

The real treasure at the end of the rainbow. (The rainbow is lower center, across the gap.)

In places, rock-like chimneys of cooled magma rise along the edges of the coast.

The large "boulder" is a volcanic magma neck. (The island in the distance is Oshima.)

These chimneys were created when lava vents opened in the earth and magma flooded up to the surface and cooled inside the conical vent. Over time, the earthen column that surrounded the magma eroded away, leaving only the cooled column of magma that had hardened in the neck of the volcanic vent. They look like boulders, but in fact they're unique geological formations.

Another unique geological feature visible on the Jogasaki Coast is columnar jointing.

Columnar Joints visible at the base of the igaigane, center frame.

Columnar joints are created when closely-spaced parallel fractures occur in cooling igneous rock (i.e., volcano barf), resulting in "columns" of prismatically-shaped rock that run in the same direction.

Close-up of columnar joints. Look at the base of the rock.

The columnar joints on the Jogasaki Coast are particularly dramatic because the surf breaks over them, creating miniature waterfalls along the columns as each wave recedes.


In typical Japanese fashion, most of the Jogasaki Coast has been designated a Geopark. A beautiful trail runs along the shore, zig-zagging along the igaigane and passing a number of spectacular deserted coves and tide pools.

The inhabitant of a Jogasaki tide pool.

I had this view entirely to myself.

Two suspension bridges cross over particularly large inlets, and the inland portions of the trail (which still have views of the sea) run through a forest filled with wild ajisai (hydrangeas).

Jogasaki forest.

So, what does this lovely place have to do with murder?

Tell me this isn't a perfect (crime) scene.

The volcanic eruption that created the Jogasaki Coast killed everything in its path--including the ecosystem that existed at the time. It took centuries for the forests to reclaim the area, and even now only certain species of hardy plants can survive on the igaigane at the edges of the sea.

Wild but beautiful.

However, the volcano's vegicidal tendencies created a unique and beautiful ecosystem, which I'm glad to see the Japanese government and people are dedicated to preserving as a wild space for people to enjoy. Signs along the coast (in English and Japanese) explain the history and ecology of the area, and as you can see from the pictures you do not have to read anything to enjoy it.

Suspension bridge, Jogasaki Coast

Then again, if you've read this far, you already know what the signs will tell you anyway.

People often ask me whether I prefer the mountains or the sea. At Jogasaki, I didn't have to choose.

. . . what about you? Do you prefer the mountains or the sea?