is a volcanic island in the Izu archipelago in the Philippine Sea approximately southeast of Tokyo, Japan. As with the other islands in the Izu Island group, Miyake-jima forms part of the Fuji-Hakone-Izu National Park. Etymology There are many theories about the origin of Miyake-jima's name. One theory claims a manuscript about the island's genesis called the Miyakeki (三宅記), written by a Shinto priest from the island, influenced the name. The manuscript explains how a deity, Mashima (三嶋), constructed his palace on the island after having built two other houses on neighbouring islands. Each of the houses had their backs facing the palace, thus giving a lined up impression. This belief is known as the 'three house theory'. Another hypothesis says that the shrines on Miyake-jima are historically related to those on Miyajima, an island in Hiroshima Bay. As there are many more speculations, the true origin cannot be known. Geography The island is a stratovolcano with a granitic composite cone, dating from the late Pleistocene period, between 10,000 and 2,000 years ago. The island has a roughly circular coastline, 88.3 kilometers in length, with an average diameter of eight kilometers. The highest elevation is an active volcano with a height of 759.390 meters. The mountain has been recorded to have erupted numerous times throughout history, and is mentioned as far back as Nara period written records. Over the past 890 years, it has erupted 13 times, including five times since the start of the Meiji period. A lava flow in 1940 killed 11 people, and other eruptions occurred in 1962 and 1983. On July 14, 2000, Mount Oyama began another series of eruptions, and by September, the island was completely evacuated. After a four-year period of volcanic emissions, residents were allowed to return permanently on February 1, 2005. After the eruption, there has been a constant flow of sulfur dioxide gas coming from Mount Oyama. Residents of the island were once required to carry gas masks with them at all times. However, masks have not been needed for years. Alarms go off if there is a dramatic increase in the levels of toxic gases in the air. Volcanic gas emissions from this volcano are measured by a Multi-Component Gas Analyzer System, which detects pre-eruptive degassing of rising magmas, improving prediction of volcanic activity. Climate Miyake-jima has a humid subtropical climate (Köppen climate classification Cfa) with very warm summers and