The , also translated from Japanese as Musashino Platform and also named Musashino Region, is a large tableland that sits between the Arakawa and Tama rivers in the

Kantō region The is a geography, geographical region of Honshu, the largest island of Japan. In a common definition, the region includes the Greater Tokyo Area and encompasses seven prefectures of Japan, prefectures: Chiba Prefecture, Chiba, Gunma Prefe ...

Honshu , historically known as , is the largest of the four main islands of Japan. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the list of islands by area, seventh-largest island in the world, and the list of islands by ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

. The

plateau In geology and physical geography, a plateau (; ; : plateaus or plateaux), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. ...

consists of an

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...

formed by the ancient Tama River, covered by a layer of

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–si ...

formed from

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

Location

The plateau is part of the

Kantō Plain The , in the Kantō region of central Honshu, is the largest plain in Japan. Its 17,000 km2 covers more than half of the region extending over Tokyo, Saitama Prefecture, Kanagawa Prefecture, Chiba Prefecture, Gunma Prefecture, Tochigi Prefe ...

. It sits northwest of

Tokyo Bay is a bay located in the southern Kantō region of Japan spanning the coasts of Tokyo, Kanagawa Prefecture, and Chiba Prefecture, on the southern coast of the island of Honshu. Tokyo Bay is connected to the Pacific Ocean by the Uraga Channel. Th ...

, in the southwest of the plain. Its northern section is in southern

Saitama Prefecture is a Landlocked country, landlocked Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Saitama Prefecture has a population of 7,338,536 (January 1, 2020) and has a geographic area of 3,797 Square kilometre, km2 ( ...

. Much of

Tokyo Tokyo, officially the Tokyo Metropolis, is the capital of Japan, capital and List of cities in Japan, most populous city in Japan. With a population of over 14 million in the city proper in 2023, it is List of largest cities, one of the most ...

, between the Tama River to the south and the Arakawa River to the north, is built on the plateau.

Origin

The Tama River carved the Okutama Mountains and deposited a large alluvial fan that spread out from Ōme. The fan is the base layer of the Musashino Plateau, and is covered by the Kantō Loam Formation, which is 5 to 15

meters The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of ...

thick. The loam is primarily andesite or basaltic sandy mud formed from volcanic ash that the wind carried west from

Mount Fuji is an active stratovolcano located on the Japanese island of Honshu, with a summit elevation of . It is the highest mountain in Japan, the second-highest volcano on any Asian island (after Mount Kerinci on the Indonesian island of Sumatra), a ...

. Two types of developed

fluvial terrace Fluvial terraces are elongated Terrace (geology), terraces that flank the sides of floodplains and fluvial valleys all over the world. They consist of a relatively level strip of land, called a "tread", separated from either an adjacent floodplai ...

s (river terraces) are found on the plateau. One is formed by the flow of the Tama River on the south side. The lowest terrace (low surface) is the Tachikawa terrace, and the terrace one step higher than that (high surface) is the Musashino terrace. The other is in the north and is thought to be a remnant of the former Tama River channel.

References

Landforms of Tokyo Landforms of Saitama Prefecture Plateaus of Japan Tables (landform) {{Regional-geology-stub