The braided course of the Jokulfell downstream from Hofsjokull.| J-STAGE
Basaltic lava field, the Svartshengi geothermal power plant (right), and the Blue Lagoon (left).| J-STAGE
Earth hummock. Earth hummocks are among the periglacial phenomena. The knoll covered with vegetation is |about 0.5 m high.| J-STAGE
Jokulsarlon lagoon. The Breidamerkurjokull glacier has been retreating since about 1920. The lagoon formed at the glacial front shows a yearly increase.| J-STAGE
Geyser Strokkur. The geyser erupts at 5-10 minute intervals.| J-STAGE
Normal fault at Thingvellir. The boundary between the North American plate on the left-hand side and the Eurasian to the right.| J-STAGE
Reykjavik is a smokeless city. Almost 100% of the electricity and the heating depends upon hydropower and geothermal energy.| J-STAGE
Valley of Eldgja. The 934-40 Eldgja eruption occurred along a 75 km-long fissure.| J-STAGE
Dettifoss waterfall. The waterfall is 44 m high. The river water is rich in suspended sediments and the waterfall volume is the greatest in Iceland.| J-STAGE
Palagonite ridge formed by subglacial eruption. Langjokull glacier in the background.| J-STAGE
Gullfoss waterfall. The two-step cataract has a total drop of 32 m.| J-STAGE
Lakagigar fissure eruption. The 1783-84 Laka- gigar eruption resulted in a great famine, due to which Iceland lost 20% of its population.| J-STAGE

Latest Issue

Journal of Geography (Chigaku Zasshi), 2018 Vol.127 No.2

2017 Vol.127 No.2

Deposits of Caldera-forming Eruptions and Post-caldera Eruptions of the Shikotsu Caldera, Hokkaido

The Shikotsu caldera in southwestern Hokkaido is a collapse caldera formed by a large ignimbrite eruption at around 46 ka. During the caldera-forming eruption, a large volume of ignimbrite was ejected from the caldera and spread in all directions. A part of the flow reached the city of Sapporo. After the caldera-forming eruption, Eniwa, Fuppushi, and Tarumae volcanoes were formed as post-caldera volcanoes. The area of Chitose and Tomakomai, located east of the Shikotsu caldera, has several key outcrops that reconstruct volcanic activities of the Shikotsu caldera. This outcrop is in Tomakomai, about 20 km southeast of the caldera. Within this outcrop, three layers of pumice-fall deposits from Tarumae volcano can be recognized on the pumice flow deposit of the caldera-forming eruption of the Shikotsu caldera. A dark-colored paleosol separating these eruption deposits shows a hiatus between these Plinian eruptions. In the distance, Tarumae volcano, one of the post-caldera volcanoes of the Shikotsu caldera, is visible.

(Photo: Mitsuhiro NAKAGAWA;
Explanation: Mitsuhiro NAKAGAWA and Nobuo GESHI)

Special Issue: Progress of Studies on Caldera-forming Eruptions and Future Problems

Overview of the Special Issue
　“Progress of Studies on Caldera-forming Eruptions and Future Problems”

Nobuo GESHI and Mitsuhiro NAKAGAWA

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 103.

DOI:10.5026/jgeography.127.103

Introduction to the Special Issue
　“Progress of Studies on Caldera-forming Eruptions and Future Problems”

Nobuo GESHI and Mitsuhiro NAKAGAWA

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 107.

DOI:10.5026/jgeography.127.107

Crustal Deformation Infers a Magma Chamber (Review Article)

Tadashi YAMASAKI

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 111.

DOI:10.5026/jgeography.127.111

Subsurface Structure of Toya Caldera, Hokkaido, Japan,
　as Inferred from CSAMT Resistivity Surveyn (Original Article)

Yoshihiko GOTO and Tohru DANHARA

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 139.

DOI:10.5026/jgeography.127.139

Eruption Age of Nakajima Volcano at Kutcharo Caldera, Hokkaido, Japan:
　Tephrochronology of Nakajima Pumice (Original Article)

Yoshihiko GOTO and Keiji WADA

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 157.

DOI:10.5026/jgeography.127.157

Structure and Development of Collapse Calderas (Review Article)

Nobuo GESHI

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 175.

DOI:10.5026/jgeography.127.175

Stratigraphy and Lithofacies of the Toya Ignimbrite in Southwestern Hokkaido, Japan:
　Insights into the Caldera-forming Eruption at Toya Caldera (Original Article)

Yoshihiko GOTO, Kazuya SUZUKI, Takashi SHINYA,
Atsuki YAMAUCHI, Masaaki MIYOSHI,
Tohru DANHARA and Akihiko TOMIYA

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 191.

DOI:10.5026/jgeography.127.191

Eruption Sequence of 60 ka Shadai Eruption, Shikotsu Volcano:
　Reexamination from Trench and Boring Surveys (Original Article)

Mizuho AMMA-MIYASAKA and Mitsuhiro NAKAGAWA

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 229.

DOI:10.5026/jgeography.127.229

Eruption Sequence of the 46 ka Caldera-forming Eruption of Shikotsu Volcano,
　Inferred from Stratigraphy of Proximal Deposits
　at South of Lake Shikotsu, Japan (Original Article)

Mitsuhiro NAKAGAWA, Mizuho AMMA-MIYASAKA, Chiharu TOMIJIMA,
Akiko MATSUMOTO and Ryoichi HASE

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 247.

DOI:10.5026/jgeography.127.247

Methods of Estimating the Durations of Super Large Eruptions
　Based on Pyroclastic Deposits (Original Article)

Takeshi HASEGAWA, Nobutatsu MOCHIZUKI and Hisashi OIWANE

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 273.

DOI:10.5026/jgeography.127.273

Large-scale Caldera-forming Eruption and Active Post-caldera Volcano:
　General Geology and Representative Outcrops of Toya Caldera and Usu Volcano,
　Southwestern Hokkaido, Japan (Letter)

Takeshi HASEGAWA, Akiko MATSUMOTO,
Akihiko TOMIYA and Mitsuhiro NAKAGAWA

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 289.

DOI:10.5026/jgeography.127.289

Erratum

Erratum: Most Recent Faulting Event in the Uemachi Fault Zone and Related Changes in the Geomorphic Environment of the Kawachi Plain, Southwest Japan [Chigaku Zasshi (Journal of Geography) Vol. 124 (2015) , No. 4, p.607-631]

Nobuhiko SUGITO and Hisao KONDO

Journal of Geography (Chigaku Zasshi), 2018, 127(2), 303.

DOI:10.5026/jgeography.127.303

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