Lakes · Hokkaido
Lake Toya
洞爺湖とうやこTōya-koA round caldera lake beside a living volcano
Lake Toya (Tōya-ko) is a near-circular caldera lake in south-western Hokkaido with a cluster of wooded islands at its centre. On its southern shore rise the active volcano Usu-zan and Showa-shinzan, a mountain born in the 1940s; the area is a UNESCO Global Geopark.
Overview
Lake Toya is an almost round lake about ten kilometres across, filling a caldera formed some 110,000 years ago. It lies in the towns of Tōyako and Sōbetsu in Iburi Subprefecture, and like Lake Shikotsu it does not freeze in winter. The islands of Nakajima rise from its centre.
The lake owes its fame as much to its southern neighbour as to itself. Usu-zan, a young volcano on the caldera rim, has erupted four times since 1910, the last time in 2000, and its eruptions created new mountains, craters and hot springs. Tōyako Onsen, the resort town on the south shore, began with springs that appeared after the 1910 eruption.
In 2008 the G8 summit was held at a hotel on the rim above the lake. The area forms the Toya Caldera and Usu Volcano UNESCO Global Geopark, where destroyed buildings and roads are preserved as eruption memorials.
Landscape and formation
A massive eruption about 110,000 years ago emptied a magma chamber and created the caldera. Nakajima formed later as a group of lava domes in its centre. Around 20,000 years ago Usu began to grow on the southern rim; it has since collapsed and been rebuilt, with eruptions in 1663, 1769, 1822, 1853, 1910, 1943–45, 1977–78 and 2000.
Showa-shinzan (398 m) rose from farmland during the 1943–45 eruption; the local postmaster Mimatsu Masao recorded its growth in the famous 'Mimatsu diagram'.
Highlights
Nakajima
中島NakajimaFour islands in the centre of the lake, the largest of which has forest trails and a deer population; reached by lake cruise.
Usu-zan
有珠山Usu-zanActive volcano on the south shore; a ropeway climbs to viewpoints over its crater and the lake.
Shōwa-shinzan
昭和新山Shōwa-shinzanLava dome that emerged from wheat fields in 1943–45, still steaming; a Special Natural Monument.
Konpira crater trail
金比羅火口災害遺構散策路Konpira Kakō Saigai Ikō SansakuroPath past buildings and a road destroyed by the 2000 eruption, above Tōyako Onsen.
Sairo viewpoint
サイロ展望台Sairo TenbōdaiViewpoint on the northern rim looking across the lake to Usu and Shōwa-shinzan.
Ecology
Nakajima's forest has been shaped by a herd of sika deer introduced in the mid-20th century. Usu's repeated eruptions make the area an outdoor laboratory for how vegetation recolonises fresh volcanic ground.
Flora
Recolonising vegetation
Pioneer plants such as knotweed and willows on the craters of 1977 and 2000.
Fauna
Sika deer of Nakajima
A herd descended from a few animals brought to the island in the 1950s–60s.
Kokanee and trout
Introduced species fished in the lake.
Culture
The lake's name comes from the Ainu to-ya, 'lake shore'. Living with the volcano is a theme of local culture: the 2000 eruption was predicted in time for an evacuation that caused no loss of life, a case studied worldwide. On summer evenings, a long-running series of fireworks is launched from boats on the lake.
Mimatsu Masao Memorial Museum
三松正夫記念館Mimatsu Masao KinenkanMuseum at the foot of Shōwa-shinzan devoted to the postmaster who documented and later bought the new mountain.
History
c. 110,000 BP
A catastrophic eruption forms the Toya caldera.
1910
An eruption of Usu creates Meiji-shinzan; hot springs appear on the lake shore, founding Tōyako Onsen.
1943–1945
Shōwa-shinzan rises from farmland during a series of eruptions.
1949
Shikotsu-Toya National Park is designated.
1977–1978
Usu erupts, damaging Tōyako Onsen and creating new craters.
2000
Usu erupts again from new vents west of the town; about 16,000 people had been evacuated beforehand.
2008
The G8 summit is held at Lake Toya.
2009
Toya Caldera and Usu Volcano becomes one of Japan's first UNESCO Global Geoparks.
Through the seasons
Spring
Cherry blossom along the south shore in early May.
Summer
Lake cruises to Nakajima and nightly fireworks during the season.
Autumn
Colours on the rim and around Usu in October.
Winter
The lake does not freeze; snow and steaming vents make striking views of Usu.
Routes and trails
Usu-zan ropeway and crater rim
Ropeway from Shōwa-shinzan to viewpoints over the summit crater; a walking trail continues along the rim.
Nishiyama crater trail
Walk through the craters and ruined roads of the 2000 eruption.
Lake circuit
Road of about 40 km around the lake, popular with cyclists.
Practical notes
- Tōya Station on the JR Muroran Line (limited expresses from Sapporo and Hakodate) is a short bus ride from Tōyako Onsen.
- Usu is an active volcano; trails may close when activity increases – check the JMA alert level.
- The lake is usually combined with Noboribetsu Onsen and the Shikotsu area.
Frequently asked questions
Is Usu volcano still active?
Yes. It has erupted roughly every 20 to 30 years in the past century, the last time in 2000, and is closely monitored by the Japan Meteorological Agency.
What is Shōwa-shinzan?
A 398 m lava dome that grew out of farmland between 1943 and 1945 beside Lake Toya.
Does Lake Toya freeze in winter?
No, it remains ice-free, like Lake Shikotsu.
How do you get to Lake Toya from Sapporo?
By limited express on the JR Muroran Line to Tōya Station, then by bus, in around two and a half hours in total; by car it takes about two hours.
Related
Sources
- 1.統計FAQ 日本の湖沼の面積 (opens in a new tab) — 総務省統計局
- 2.日本ジオパークネットワーク (opens in a new tab) — 日本ジオパークネットワーク
- 3.支笏洞爺国立公園 (opens in a new tab) — 環境省
- 4.気象庁 火山 (opens in a new tab) — 気象庁