A Bit of Context
Miyakejima, or Miyake Island, is one of the Izu-shoto, the chain of islands that begins just beyond of Tokyo Bay and continues south along the juncture of two continental plates. All are to some degree volcanic. Miyake in most cases means “royal estate,” but here it probably remembers an older word, yake, that means “burning.” Like Stromboli, the island is essentially one big volcano, Mount Oyama.
During the last century, the volcano was fairly regular in its habits. Every twenty-odd years, a vent would open and pour lava down one face of the mountain, or a new cinder cone would be thrown up. This happened in 1940, 1962 and 1983. Lava flows are not good if they happen to end up in your backyard, but they move slowly and can usually be seen coming. At the old summit, all was relatively quiet. The crater lake became a tourist site, with a visitor’s center, pathways to scenic views, a gently steaming fumarole surrounded by tropical flowers.
But in 2000 the volcano broke character. The pressure in the magma chamber had built up faster than any small pressure valve could relieve, and the result was what volcanologists call a Plinian eruption – sudden, violent, voluminous, and with a bang. (There are also super-Plinian eruptions, but records of these, as well as of the populations that experience them, tend not to survive).
Between June and August, there were three such major eruptions. Luckily, they all went up rather than sideways, or the result would have been catastrophic. As it was, no one died, but authorities were taking no chances, and the evacuation began. It was not until five years later that any of the island’s nearly four thousand residents were permitted to return. Not all of them did.