LAND
The islands of Japan are the exposed tops of massive undersea ridges
that rise from the floor of the Pacific Ocean on the eastern edge of the Asian
continental shelf. The islands lie between the Japan Deep a north-south,
28,000-foot-deep trench in the Pacific and the 10,000-12,000-foot-deep Sea of
Japan. The Japan Deep is east of the islands; the Sea of Japan, west of the
islands. The islands of Japan are geologically young and unstable. They have
been subjected to considerable folding, faulting, and volcanic activity. As a
result, the land surface of the Japanese islands is dominated by mountains and
hills which divide them into hundreds of subunits. This creates a landscape of
great variety and beauty and gives Japanese life a small-scale compactness. The
largest and highest mountain mass, part of which is known as the Japanese Alps,
is in central Honshu. From it mountain chains extend northward to Hokkaido and
southwest to Shikoku and Kyushu. These mountain chains are gouged by many short
river valleys and interrupted by many small lowland plains.
Only one fourth of Japan's land surface has a slope of
less than 15 degrees. Most Japanese plains have been formed by river deposits
and lie along the seacoast of the nation. The largest lowland, the Kanto Plain
of east-central Honshu, has an area of only about 6,000 square miles. It
contains the city of Tokyo. Among the nation's smaller plains are the Nobi
(Nagoya) Plain and the Kansai (Osaka, Kyoto, and Kobe) Plain. The numerous
rivers of Japan are short and have small drainage basins. Only two of them are
more than 200 miles long the Shinano and the Tone, both on Honshu. Of the two,
the Shinano is the longest (228 miles) and the Tone drains the largest area
(about 7,100 square miles). Japan's rivers generally have steep gradients and
carry heavy loads of sediment from the mountains to the lowlands. On the
lowlands they are usually shallow and braided and flow through gravel-filled
beds. Often they have built-up natural levees and are elevated above the river
plains. Their flow rates vary greatly with the seasonal rain.
Although of little use for navigation, the rivers of
Japan are used intensively for irrigation, urban water supply, and the
generation of electricity. Floods are common, especially during the typhoon
season, and are highly destructive in the heavily populated river valleys and
plains. Japan has few lakes. The largest is Lake Biwa, in west-central Honshu.
Japan's coastline is unusually long in relation to the nation's total land
area. The Pacific coast has many deep indentations, among them Tokyo and Ise
bays on Honshu and the Inland Sea between Honshu and Shikoku. The indentations
are separated by rugged peninsulas and headlands. Among them are the Boso and
Izu peninsulas. The west coast of Kyushu is also deeply indented, and there are
many small offshore islands. The Sea of Japan coast of Honshu, however, is much
straighter and has long stretches of sand dunes and beach ridges.
Japan's numerous volcanoes and frequent earthquakes
are evidence of the instability of the rocks underlying the country. It has
about 200 volcanoes and volcanic groups, of which about 60 have been active in
recorded history. Some of the volcanoes are cone-shaped and rise to the highest
elevations in Japan, while others are calderas, or lake-filled depressions where
cones once stood. Mount Fuji (12,389 feet), the famous volcanic cone, is the
highest peak in Japan. It has been dormant since 1707. Mount Asama in central
Honshu and Mount Sakurajima in southern Kyushu are well-known active volcanoes.
Among the most notable calderas are Mount Aso in Kyushu and Mount Akan in
Hokkaido. There are hot springs in the volcanic zones. Undersea earthquakes in
the northern Pacific basin stir up unusually large tsunamis, or "tidal
waves," which are very destructive when they reach the Japanese coast.
Severe earthquakes that do damage over small areas occur about every five or
six years in Japan. One of the worst was the Great Kanto Earthquake of 1923,
which combined with fire and tsunami to wipe out much of Tokyo and Yokohama. More
than 100,000 lives were lost.
CLIMATE
For a small nation, Japan has a great variety of
climatic conditions. This is because its islands have a long latitudinal spread
and are in the zone where the conflicting air masses of the Asian continent and
of the Pacific Ocean meet and interact. The continental air masses make for
more extreme temperatures, both in winter and in summer, and result in large
annual temperature ranges. But their effect is moderated by the strong marine
influence, which also produces high humidity and abundant rainfall. Japan's
rugged topography also makes for many local variations in weather and climate.
During the winter, Japan is primarily under the influence of cold air masses
moving out of Siberia, deep in the Asian interior. Biting northwest winds pass
over the Sea of Japan and cross the islands of Japan. Moisture picked up over
the Sea of Japan is deposited on Japan's west coast in the form of heavy snows
that are among the deepest in the world.
During the summer, Japan is under the influence of air
moving in from the Pacific Ocean. Southeast winds prevail, making the summer
months warm and humid. The cycle of the seasons brings frequent, often sharp,
changes in the weather, especially during the spring and autumn months. Japan's
climate, especially along the coasts, is also affected by two ocean currents
the warm Kuroshio, or Japan Current, from the south, and the cold Oyashio, or
Okhotsk Current, from the north. The two currents meet off northeastern Honshu.
The Kuroshio, on the lee side of Japan in winter, has little warming effect on
land temperatures. The Tsushima Current, a branch of the Kuroshio, passes into
the Sea of Japan by way of Korea Strait and slightly warms offshore waters. The
Oyashio reduces summer temperatures and creates dense fog banks off the coasts
of northeastern Honshu and Hokkaido.
Virtually all of Japan except parts of eastern
Hokkaido averages more than 40 inches of precipitation annually. Several
coastal mountain areas in Honshu get more than 120 inches. Areas around the
Inland Sea, in eastern Honshu north of Tokyo Bay, and in western Hokkaido
average 40 to 60 inches. The Sea of Japan coast gets more precipitation in
winter, largely in the form of snow, than it does in summer. The reverse is true
for the Pacific coast, where summer precipitation exceeds that of winter. In
northern Hokkaido, snow falls an average of 130 days per year; along the Sea of
Japan, 80 days; on the Pacific coast south and west of Tokyo Bay, only 10 days.
Japan has rainy seasons in June and in September, though there is some
precipitation throughout the year. The main, June rainy season is called the
baiu, or tsuyu, and has many days of continuous rain. The September rainy
season is called the shurin. It is associated with occasional typhoons,
tropical storms like the hurricanes of southeastern North America. These move
to the north and northeast in a clockwise arc from their spawning grounds east
of the Philippines. When they strike Japan, they cause destructive floods and
landslides. However, they also restore water levels in rivers and reservoirs,
which drop during the dry days of late summer. Typhoons bring roughly one third
of the rain that falls annually on the Pacific coast. In 1959, one of the worst
typhoons of modern times tore through the city of Nagoya and across central
Honshu. Approaching typhoons are carefully watched by the Japan Meteorological
Agency, and special radio and television bulletins are issued on their
progress.
Seasonal temperatures in Japan increase from north to
south. Average January temperatures are 15 to 20 F in Hokkaido; 35 to 40 in
central Honshu; and 45 in southern Kyushu. There is little difference in winter
temperatures between the west and east coasts, though the skies are more overcast
on the west coast and clearer and sunnier on the east coast. Summers are sultry
throughout Japan. July temperatures average 77 to 80 in Kyushu, Shikoku, and
southern and central Honshu; 72 to 75 in northern Honshu; and a cooler 65 to 70
in Hokkaido. The clear, hot weather of summer arrives in mid-July, following
the baiu rains. It is ended by the shurin rains. The length of the frost-free,
or growing, season ranges from 250 days or more along the Pacific coast south
from Tokyo Bay to only 120 days in central Hokkaido. Early autumn frosts in
northern Japan and late spring frosts in central and southern Japan pose a
seasonal threat to farming.
PLANT AND ANIMAL LIFE
The trees, shrubs, and flowering plants of Japan are
as varied as its topography and climate. Forests cover most of the land surface
that has not been cleared by man. Coniferous, broadleaf, and mixed forests are
the three main types. Among the conifers, pine, cypress, hemlock, cedar, fir,
and spruce are commercially valuable. The numerous broadleafs include oak,
maple, ash, birch, beech, poplar, chestnut, and horse chestnut. Subtropical
forms such as bamboo and palms grow as far north as central Honshu. Many native
plant species have been destroyed or reduced by humans, and new species from
the Asian mainland have had to be introduced. Large virgin-forest areas have
been preserved in parks.
Large mammals include bear, badger, otter, mink, deer,
fox, and walrus. One monkey, the Japanese macaque, is found as far north as
Hokkaido. Adjacent seas are the home of whales and porpoises. Japanese bird
species include many water and wading birds, hawks, pheasants, peacocks, doves,
owls, and woodpeckers. Among the reptiles are sea turtles, tortoises, lizards,
and snakes. The sea abounds with hundreds of fish species. Salmon, sardine, sea
bream, tuna, trout, mackerel, cod, and mullet are among those caught by
commercial fishermen. Tropical varieties accompany the warm waters of the Kuroshio
as far north as Tokyo Bay. The raising of goldfish for decorative purposes is a
Japanese specialty.
