At S. dei M. Hida, a mountainous territory rich in vegetation begins, consisting of granite rocks on which the intensity of erosion is visible, rarely higher than 1000 m. In height: it is the M. Chūgoku chain that crosses the peninsula of the same name and seems to continue in Kyūshū in the chain of M. Tsukushi, more varied in geological formations.
To the south-east of Hondo, under the Alpine region, gigantic faults have given rise to three fracture chains: the M. Suzuka-Ibuki, the M. Kasagi-Hiei and the M. Kongō, parallel and limiting with their flanks two wide valleys of sinking. The first of these contains Lake Biwa, the largest in the Empire, and ends in the north on the coasts of rías of Tsuruga and Wakasa; the other constitutes an important region from a historical point of view, since it can well be said to be the cradle of ancient Japanese civilization. It is in it that we find Nara, the first capital that Japan had, and Kyōto, which was the capital until 1868, whose name is linked to a period of wonderful literary and artistic flourishing. To the west of M. Kongō, the Settsu plain, due to its position, has assumed a first-rate place in the modern life of the nation, centralizing, in a large metropolis like Ōsaka (more than 2 million residents), the commercial activity of it.
The archipelago’s position on the edge of the great Pacific basin means that it participates with its numerous volcanoes in the so-called “circle of fire” that surrounds it. 165 is the number of known volcanoes throughout the country, of which 54 (according to some 59) are active. The term active or inactive, moreover, is relative, since it is not uncommon for volcanoes considered to be inactive to have had disastrous and terrible awakenings of their activity. The case of Bandaisan, north of Lake Inawashiro, which, always considered an extinct volcano, had a terrifying eruption on May 15, 1888 that destroyed its crater and formed another larger one. Japanese volcanoes are usually made up of andesite, often basaltic, and derivatives. The study of their distribution makes it possible to distinguish 10 volcanic chains or zones (see map on page 6), all arranged longitudinally to the archipelago, with the exception of one, the area of Fuji, the largest of all, which goes from the Sea of Japan to the Pacific crossing Hondo in the Fossa Magna. The Aso volcano, in the center of Kyūshū, has one of the largest craters in the world (22 km in diameter); the highest volcanic peak in Japan is Fuji (3778 m.).
The history of the country recorded, before 1895, 18 violent eruptions, 39 of which belong to the Aso alone, followed by the Sakurajima and the Asamayama, with 22 each. The latter, in particular, is sadly famous for the violence of its paroxysms and the Tōkyō region has increasingly suffered from its proximity. In its eruption of 1873, for example, there were several hundred victims and the quantity of ashes erupted was enough to cover an area of 10,000 sq km. devastating fields and crops; in the other of 1912 blocks of 50 cubic meters were projected upwards. and the displacement of air was such as to cause serious damage to buildings located 15 km. far. In the last fifty years the activity of the Japanese volcanoes has been mainly of the Strombolian type; some, such as Atosanupuri, Meakan, Asahidake and others, have solfataras activity. Volcanoes are characteristic elements of the Japanese relief and landscape; their daring cones, more or less rounded at the top, with an often elegant and regular profile, are the most suggestive one can imagine; their lavas often produce barriers that give rise to those multiple waterfalls which are one of the natural beauties of Japan.
According to healthvv, another of the scourges of the country are earthquakes. Recent statistics average 4-5 tremors per day, with a disastrous tremor every 6-7 years. This condition of things has obliged since time immemorial the exclusive use of wood in buildings, limiting the floors of these to one or two floors; naturally the fires are very frequent, but the forests abound and are rich. Earthquakes are often to be related to volcanic activity, the resumption of which they are then usually heralds in this case, however, they have a limited intensity and extent, and their effects are not comparable to those, much more disastrous, of earthquakes of nature. tectonics. The study of the epicenters of the 51 catatrophic earthquakes that the history of the country remembers from 1546 to today, has made it possible to distinguish 6 main seismic zones, some of which coincide roughly with volcanic areas; the most important is that of Fuji, which also includes the Tōkyō region, one of the most affected. The memory of the last catastrophic earthquake of 1923 is still fresh, which cost the lives of 150,000 people, destroyed Yokohama completely, Tokyo by half and caused vast fires everywhere; the reconstruction work, started immediately with great energy by the government, required financial efforts so conspicuous, as to have profound repercussions on the economic development of the country. Half Tōkyō and caused vast fires all over; the reconstruction work, started immediately with great energy by the government, required financial efforts so conspicuous, as to have profound repercussions on the economic development of the country. Half Tōkyō and caused vast fires all over; the reconstruction work, started immediately with great energy by the government, required financial efforts so conspicuous, as to have profound repercussions on the economic development of the country.
Tsunamis (Japanese tsunamis), which frequently sweep the coastal plains, especially the eastern ones, can be attributed to submarine earthquakes. One of them, in 1854, almost completely destroyed the coastal town of Kamaishi, northeast of Hondo, and cost the lives of 70% of the population.
In the face of such disastrous manifestations of endogenous activity, the benefits of a conspicuous wealth of thermal and mineral springs that the country enjoys are in return. Up to now, 951 hot and 155 cold springs are known; among all, 250 possess radioactive properties. In general they are of volcanic origin, but there is no lack of tectonic ones. Most of them have therapeutic properties that have made many spas renowned and very popular. Their chemical composition is extremely varied and it can be said that all types of known mineral waters are widely represented. Radioactivity is closely related to the geology of the region, not to the chemical composition of the water. The most strongly radioactive sources, such as eg. the thermal one of Misasa (142. 14 Mache units) and the cold one of Masutomi (1425 u. M.) are located in granite soils. As for the temperature, some few measure more than 100 °; most have temperatures between 25 ° and 90 °. Among the best known and most accredited spas are those of Beppu and Unzen, on the island of Kyūshū; of Atami, of Higashiyama, of Yumoto, of Hakone, of Arima, of Kusatsu, on the island of Hondo; of Noboribetsu, on the island of Yezo.