Japan boasts approximately 27,000 hot spring sources, making it one of the top countries in the world for hot springs. Why does Japan have so many hot springs?

The answer lies in its volcanoes. Japan is one of the world's leading volcanic nations, and these volcanoes are what create hot springs.

The Pacific Ring of Fire

Japan is located in the "Pacific Ring of Fire."

The Pacific Ring of Fire is a volcanic belt that encircles the Pacific Ocean, including the Japanese archipelago, the Aleutian Islands, and the west coasts of North and South America.

About 75% of the world's active volcanoes are concentrated in this volcanic belt. Japan has about 110 active volcanoes, accounting for approximately 7% of the world's active volcanoes.

In such a small land area, there are so many volcanoes. This is the main reason why Japan is a hot spring powerhouse.

Why Japan Has So Many Volcanoes

The reason Japan has so many volcanoes is due to the movement of tectonic plates.

The Japanese archipelago is located at the convergence of four tectonic plates: the Pacific Plate, the Philippine Sea Plate, the Eurasian Plate, and the North American Plate.

The oceanic plates (Pacific Plate, Philippine Sea Plate) subduct beneath the continental plates (Eurasian Plate, North American Plate). This subduction generates magma.

When magma erupts onto the surface, a volcano is born. Japan is situated in this "subduction zone," which is why it has so many volcanoes.

The Connection Between Volcanoes and Hot Springs

Volcanoes and hot springs are deeply connected.

Magma Heats Underground Water

Beneath volcanoes lies magma, with temperatures ranging from about 800 to 1,200°C.

This magma heats rainwater and snowmelt that have seeped underground. The heated underground water becomes hot springs.

As the temperature rises, the volume of water expands, increasing pressure. This pressure causes the hot springs to gush to the surface.

Volcanic Gases Create Hot Spring Components

Volcanoes emit various gases, such as hydrogen sulfide, carbon dioxide, and hydrogen chloride.

These gases dissolve into underground water, forming the components of hot springs. Sulfur springs, carbonated springs, and acidic springs are created.

Due to volcanic gases, hot springs become more than just "hot water"; they become "mineral-rich hot springs."

Volcanic Hot Springs and Non-Volcanic Hot Springs

Hot springs are classified into volcanic hot springs and non-volcanic hot springs.

Volcanic Hot Springs

Characteristics: Hot springs created by volcanic activity. They are high in temperature and rich in minerals.

Spring Quality: Common types include sulfur springs, acidic springs, and chloride springs.

Examples: Kusatsu Onsen, Hakone Onsen, Beppu Onsen, Noboribetsu Onsen.

Non-Volcanic Hot Springs

Characteristics: Hot springs formed independently of volcanic activity. Underground water heated deep below the surface.

Spring Quality: Common types include simple springs and bicarbonate springs.

Examples: Arima Onsen (Hyogo Prefecture), Misasa Onsen (Tottori Prefecture), Dogo Onsen (Ehime Prefecture).

Most of Japan's hot springs are volcanic, but non-volcanic hot springs also exist.

Is Arima Onsen Non-Volcanic?

Arima Onsen is one of Japan's three famous hot springs. However, there are no active volcanoes nearby. Why does it have high-temperature, mineral-rich hot springs?

It is believed that as the Philippine Sea Plate subducts, seawater components are carried deep underground, heated, and then emerge. Although unrelated to volcanoes, it is a hot spring created by plate movement.

Thus, Japan's hot springs are born not only from volcanoes but also from tectonic plate movements.

The Benefits of Volcanic Japan

Volcanoes bring disasters such as earthquakes and eruptions. However, they also provide significant benefits.

Hot Springs: Japan is one of the world's leading hot spring nations.

Geothermal Power: A renewable energy source unique to volcanic countries.

Beautiful Landscapes: The scenery created by volcanoes, such as Mount Fuji and Mount Aso, is stunning.

Fertile Land: Volcanic ash creates soil suitable for agriculture.

Volcanoes support Japan's culture and economy.

Volcanoes and Hot Springs Around the World

Other volcanic countries besides Japan also have many hot springs.

Iceland: A volcanic island in the North Atlantic. Rich in hot springs and active in geothermal power.

New Zealand: Active volcanic activity. Many hot spring areas like Rotorua.

Italy: Mount Vesuvius, Mount Etna, etc. Hot spring culture dates back to ancient Rome.

United States: Famous for the geysers in Yellowstone National Park.

Where there are volcanoes, there are hot springs. This is a universal rule.

Hot Springs and Japanese Culture

The Japanese have lived alongside volcanoes and hot springs.

Hot springs are deeply rooted in Japanese life. They relieve fatigue, heal ailments, and enhance travel experiences. Hot springs are a part of Japanese culture.

Being a volcanic nation carries disaster risks, but it also brings the great blessing of hot springs.

Conclusion

The reason Japan is a hot spring powerhouse is due to its volcanoes. Japan is located in the Pacific Ring of Fire and has about 110 active volcanoes.

Magma from volcanoes heats underground water, and volcanic gases create hot spring components. This is the mechanism by which hot springs are born.

Most of Japan's hot springs are volcanic, but non-volcanic hot springs like Arima Onsen also exist. Tectonic plate movements can also create hot springs.

Volcanoes bring disasters, but they also bring the blessing of hot springs. The Japanese have lived alongside volcanoes and hot springs, and this relationship will continue in the future.