Geography

Japan is an island nation in East Asia comprised of a large stratovolcanic archipelago extending along the Pacific coast of Asia. Measured from the geographic coordinate system, Japan is 36° north of the equator and 138° east of the Prime Meridian. The country is north-northeast of China and Taiwan (separated by the East China Sea) and slightly east of Korea (separated by the Sea of Japan). The country is south of Siberia in Russia.

The main islands, sometimes called the 'Home Islands', are (from north to south) Hokkaido, Honshu (the 'mainland'), Shikoku and Kyushu. There are also about 3,000 smaller islands, including Okinawa, and islets, some inhabited and others uninhabited. In total, Japan's territory is 377,835 sq km, of which 374,744 sq km is land and 3,091 sq km water. This makes Japan's total area approximately 1.5 times larger than that of the UK.

Composition and Topography

About 73 percent of Japan is mountainous, with a mountain range running through each of the main islands. Japan's highest mountain is Mt. Fuji, with an elevation of 3,776 m (12,388 feet). Since so very little flat area exists, many hills and mountainsides are cultivated all the way to the top. As Japan is situated in a volcanic zone along the Pacific deeps, frequent low-intensity earth tremors and occasional volcanic activity are felt throughout the islands. Destructive earthquakes occur several times a century. Hot springs are numerous and have been exploited as an economic capital by the leisure industry.

The mountainous islands of the Japanese Archipelago form a crescent off the eastern coast of Asia. They are separated from the mainland by the Sea of Japan, which historically served as a protective barrier. The country consists of four principal islands: Hokkaido, Honshu, Shikoku, and Kyushu; more than 3,000 adjacent islands and islets, including Oshima in the Nampo chain; and more than 200 other smaller islands, including those of the Amami, Okinawa, and Sakishima chains of the Ryukyu Islands. The national territory also includes the small Bonin or Ogasawara Islands, which include Iwo Jima and the Volcano Islands (Kazan Retto), stretching some 1,100 kilometres from the main islands. A territorial dispute with Russia, dating from the end of World War II, over the two southernmost of the Kuril Islands, Etorofu (Iturup) and Kunashiri, and the smaller Shikotan and Habomai Islands northeast of Hokkaido remains a sensitive spot in Japanese-Russian relations as of 2005. Excluding disputed territory, the archipelago covers about 377,000 square kilometres. No point in Japan is more than 150 kilometres from the sea.

The four major islands are separated by narrow straits and form a natural entity. The Ryukyu Islands curve 970 kilometres southward from Kyushu.

The distance between Japan and the Korean Peninsula, the nearest point on the Asian continent, is about 200 kilometres at the Korea Strait. Japan has always been linked with the continent through trade routes, stretching in the north toward Siberia, in the west through the Tsushima Islands to the Korean Peninsula, and in the south to the ports on the south China coast.

Mountains and Plains

The Japanese islands are the summits of mountain ridges uplifted near the outer edge of the continental shelf. About 75 percent of Japan's area is mountainous, and scattered plains and intermontane basins (in which the population is concentrated) cover only about 25 percent. A long chain of mountains runs down the middle of the archipelago, dividing it into two halves, the 'face,' fronting on the Pacific Ocean, and the 'back,' toward the Sea of Japan. On the Pacific side are steep mountains 1,500 to 3,000 metres high, with deep valleys and gorges.

Central Japan is marked by the convergence of the three mountain chains (the Hida, Kiso, and Akaishi mountains) that form the Japanese Alps (Nihon Arupusu), several of whose peaks are higher than 3,000 metres. The highest point in the Japanese Alps is Kitadake at 3,193 metres. The highest point in the country is Mount Fuji (Fujisan, also erroneously called Fujiyama), a volcano dormant since 1707 that rises to 3,776 metres above sea level in Shizuoka Prefecture. On the Sea of Japan side are plateaus and low mountain districts, with altitudes of 500 to 1,500 metres.

None of the populated plains or mountain basins is extensive in area. The largest, the Kanto Plain, where Tokyo is situated, covers only 13,000 square kilometres. Other important plains are the Nobi Plain surrounding Nagoya, the Kinki Plain in the Osaka-Kyoto area, the Sendai Plain around the city of Sendai in north-eastern Honshu, and the Ishikari Plain on Hokkaido. Many of these plains are along the coast, and their areas have been increased by reclamation throughout recorded history.

The small amount of habitable land prompted significant human modification of the terrain over many centuries. Land was reclaimed from the sea and from river deltas by building dikes and drainage, and rice paddies were built on terraces carved into mountainsides. The process continued in the modern period with extension of shorelines and building of artificial islands for industrial and port development, such as Port Island in Kobe and the new Kansai International Airport in Osaka Bay. Hills and even mountains have been razed to provide flat areas for housing.

Rivers and Coastline

Rivers are generally steep and swift, and few are suitable for navigation except in their lower reaches. Most rivers are fewer than 300 kilometres in length, but their rapid flow from the mountains provides a valuable, renewable resource: hydroelectric power generation. Japan's hydroelectric power potential has been exploited almost to capacity. Seasonal variations in flow have led to extensive development of flood control measures. Most of the rivers are very short. The longest, the Shinano River, which winds through Nagano Prefecture to Niigata Prefecture and flows into the Sea of Japan, is only 367 kilometres long. The largest freshwater lake is Lake Biwa, northeast of Kyoto.

Extensive coastal shipping, especially around the Inland Sea (Seto Naikai), compensates for the lack of navigable rivers. The Pacific coastline south of Tokyo is characterised by long, narrow, gradually shallowing inlets produced by sedimentation, which has created many natural harbours. The Pacific coastline north of Tokyo, the coast of Hokkaido, and the Sea of Japan coast are generally unindented, with few natural harbours.

Environmental Issues

Current environmental issues in Japn include:

• air pollution from car emissions in urban area suspected for causing Asthma
• over-enrichment of lakes and reservoirs degrading water quality for aquatic life
• quota for fisheries imposed on Japanese fishing fleets
• over-fish farming causing degrading water quality for aquatic life
• biodiversity threatened by foreign animals, fish, insects, and plants

Natural Hazards

Ten percent of the world's active volcanoes - forty in the early 1990s (another 148 were dormant) - are found in Japan, which lies in a zone of extreme crustal instability. As many as 1,500 earthquakes are recorded yearly, and magnitudes of four to six on the Richter scale are not uncommon. Minor tremors occur almost daily in one part of the country or another, causing slight shaking of buildings. Major earthquakes occur infrequently; the most famous in the twentieth century was the great Kanto earthquake of 1923, in which 130,000 people died. Undersea earthquakes also expose the Japanese coastline to danger from tsunami tidal wave.

Japan has become a world leader in research on causes and prediction of earthquakes. The development of advanced technology has permitted the construction of skyscrapers even in earthquake-prone areas. Extensive civil defence efforts focus on training in protection against earthquakes, in particular against accompanying fire, which represents the greatest danger.

Another common hazard are typhoons (taifu) that reach Japan from the Pacific.