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Research: Fuji developing a more explosive style? 6 May 2010

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‘Rumbles hint that Mount Fuji is getting angry’, says the rather sensationalized headline that New Scientist has stuck over their report of a new study of Mount Fuji. There’s no suggestion in the original research paper that Fuji is ‘getting angry’, or even slightly annoyed, just a new theorization of the processes that may be causing Fuji’s magmas to become more andesitic to dacitic, thus tending towards a more explosive eruptive style.

The paper, ‘Crypto-magma chambers beneath Mt. Fuji’ by Takayuki Kaneko et al (JVGR 2010, in press) notes that Fuji’s eruptive history has been characterized by basaltic activity with occasional explosive eruptions involving andesitic to dacitic lavas. Studies of Fuji’s lavas using air-fall scoria, however, indicate an increase in silica content over time: Kaneko proposes a two-level magma chamber system to account for this, with basaltic magma at the deep level and more silicic magma at the shallower level. The increasing level of silica, suggests Kaneko, ‘could result from the combination of repeated magma mixing between the two end-member magmas and fractional crystallization processes in each magma chamber’.

The upward trend of SiO2 … seems to continue to the present. In the last several thousand years, explosive eruptions involving a small volume of andesitic magma were repeated sporadically … Such andesitic or dacitic products have not been found from the older periods of Fuji–Ko-Fuji to the middle stage of Shin-Fuji volcanoes. This may suggest that, in the last several thousand years, the composition of the magma in the shallow chamber has become more SiO2-rich than ever.

The New Scientist article says that Kaneko interprets the low-frequency earthquakes detected beneath Fuji in 2000 and 2001 as possible evidence for magma injections into the lower chamber, ‘and adds he would not be surprised if Fuji erupts in the very near future’. That’s the ‘Fuji getting angry’ bit, and it’s stretching things somewhat on the basis of this research. The paper itself simply concludes with the suggestion that ‘Fuji may have entered a stage with the potential for explosive eruptions involving andesitic to dacitic magmas’.

  • Takayuki Kaneko, Atsushi Yasuda, Toshitsugu Fujii and Mitsuhiro Yoshimoto, ‘Crypto-magma chambers beneath Mt. Fuji’, Journal of Volcanology & Geothermal Research, article in press 2010 [doi:10.1016/j.jvolgeores.2010.04.002]

News
Rumbles hint that Mount Fuji is getting angryNew Scientist, 5 May 2010

Information
Global Volcanism Program: Fuji – information about Fuji from the GVP (0803-03=)
Volcano Research Center – the University of Tokyo’s Volcano Research Center

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Fukutoku-Okanoba at the NASA Earth Observatory 12 February 2010

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Submarine Volcano Fukutoku-Okanoba Erupts (NASA Terra image, 9 February 2010)

Undersea volcano Fukutoku-Okanoba in the Japanese Volcano Islands erupted a few days ago, producing steam and ash, and discolouring the surrounding water. The NASA Earth Observatory has two nice images of this event captured on 9 and 11 February 2010. The first (detail above) was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite on 9 February 2010, while the second (detail below) comes from the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite and was captured on 11 February 2010.

Submarine Volcano Fukutoku-Okanoba Erupts (NASA EO-1 image, 11 February 2010)

(Thanks to the NASA Earth Observatory team for citing this blog as a source.)

Information
Global Volcanism Program: Fukutoku-Okanoba – information from the GVP about Fukutoku-Okanoba (0804-13=)

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Sparks fly in Sakura-jima eruption 11 February 2010

Posted by admin in eruptions, Japan, Sakura-jima.
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Sakura-jima eruption, 8 February 2010 (Kago-net)

Here’s some serious volcanic lightning. As reported in this week’s SI/USGS Weekly Volcanic Activity Report, Sakura-jima volcano in southern Japan – always highly-active – erupted spectacularly on 8 February, producing lava fountaining up to 1 km in height, showering its flanks with incandescent material, and throwing up a very dense ash plume positively pulsating with lightning. There’s a great video at Kago-net showing all this activity, and I can’t resist showcasing some captures from that video here.

(There has been some interesting research on volcanic lightning recently, occasioned by Redoubt’s 2009 eruption. See Eruptions for background and links, and this article from National Geographic News.)

Sakura-jima eruption, 8 February 2010 (Kago-net)

Sakura-jima eruption, 8 February 2010 (Kago-net)

Sakura-jima eruption, 8 February 2010 (Kago-net)

Sakura-jima eruption, 8 February 2010 (Kago-net)

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Undersea eruption south of Japan caught on video 4 February 2010

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Fukutoku-Okanoba undersea volcano erupting, February 2010 (stills from Japanese Coastguard video)

Fukutoku-Okanoba is a submarine volcano which is part of the Volcano Islands group, which is about 1000 km south of the main Japanese archipelago. Submarine, but only just, for its summit lies a mere 14 metres beneath the surface. This week it has been erupting, the first eruption (or, if you are British news channel ITN, ‘smoke explosion’) of Fukutoku-Okanoba since 2005, and the Japanese Coastguard caught the eruption on video. Four still images from the video can be seen above, showing steam billowing out and some dark-grey ash erupting from the ocean.

[Thanks to Ton van der Aa for the tip.]

News
Underwater volcano erupts in smoke explosion – ITN, 4 February 2010
Mogelijke uitbarsting zeevulkaan gefilmd – NUVideo, 4 February 2010
Undersea volcano close to Iwo Jima blows topMainichi Daily News, 4 February 2010

Information
Global Volcanism Program: Fukutoku-Okanoba – information from the GVP about Fukutoku-Okanoba (0804-13=)

The Volcanism Blog

A plume from Sakura-jima 30 October 2009

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Plume from Sakura-jima, 30 October 2009

Sakura-jima on the southern Japanese island of Kyushu is one of the most active volcanoes on earth: there is nearly always a current Volcanic Ash Advisory reporting explosions and emissions from its Minami-dake summit cone, which has been the focus of eruptive activity for about 5000 years.

Sakura-jima sits in Kagoshima Bay, the northern portion of which is formed by Aira Caldera, created in a very large eruption ~22,000 years ago. The volcano has developed on the southern edge of the caldera, and was an island until erupted material joined it to the Osumi Peninsula to the east during the major eruption of 1914. On the western rim, meanwhile, sits the city of Kagoshima, population 600,000.

In the image above, captured by NASA’s Terra satellite on 30 October 2009, Sakura-jima is releasing a grey ashy plume which crosses the Satsuma Peninsula to the west of the volcano and spreads out over the East China Sea. The plume crosses directly over the city of Kagoshima, where ashfall from Sakura-jima is a frequent occurence. The general haziness of the image is not the result of the eruption, but of air pollution blowing over from China.

Click here to see the original uncropped image (1 pixel = 250 m) at the NASA MODIS Rapid Response site. Many thanks to Robert Simmon of the NASA Earth Observatory for providing this image.

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The vanishing views of Fuji 13 October 2009

Posted by admin in Fuji, Japan, volcano culture.
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Mt Fuji from Nippori Fujimi slope on 18 November 2000 (photo by Mr Naofumi Nakajima).
Mt Fuji from Nippori Fujimi slope on 18 November 2000 (photo by Mr Naofumi Nakajima).

Among the many ways in which human beings interact with volcanoes, one of the most important but also least tangible and hardest to quantify is the simplest of all: looking.

Volcanoes are beautiful, often dramatic elements of the landscape, and people like to look at them. But views are fragile things, particularly where volcanoes are close to constantly-changing urban areas in which the construction of buildings and the effects of pollution mean the obstruction of once-valued views. Perhaps the most notable such case is Mount Fuji, and the New York Times‘s ‘Tokyo Journal’ has a report on the efforts of some Tokyo residents to fight back against the loss of treasured views of Fuji:

Protecting a building or a park may be one thing, but how do you protect a view? Saving the view from Nippori’s Fujimizaka would require capping building heights within an elongated fan-shaped corridor three miles long and up to 1,000 feet wide across densely populated neighborhoods. So far, the society has met stiff resistance from city officials and developers in Tokyo, whose properties rose rapidly from the postwar ashes thanks in part to unrestrained construction.

For centuries, the views of Mount Fuji offered by many parts of the Tokyo region have been a celebrated part of Japanese culture: but as Tokyo’s skyscrapers have climbed into the sky, the views have disappeared. Of the sixteen areas of central Tokyo called Fujimizaka, ‘the slope for seeing Mount Fuji’, there is now only one, in Nippori, from which the volcano can still be seen – just. The threat to this last remaining view of Fuji provoked the establishment of the Citizens’ Alliance to save the Fuji-view (CASF): the picture at the top of this post, from the CASF website, shows what they are up against.

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Saturday Volcano Art: Katsushika Hokusai, ‘Mount Fuji seen through cherry blossom’ (c.1834) 12 September 2009

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Katsushika Hokusai, 'Mount Fuji seen through cherry blossom' (c.1834) - detail

Unfortunately there is no time for a detailed ‘Saturday Volcano Art’ essay this week, so please just enjoy this tranquil image of Mount Fuji by the Japanese artist and printmaker Katsushika Hokusai (1760-1849), ‘Mount Fuji seen through cherry blossom’, from One Hundred Views of Mount Fuji (1834).

Katsushika Hokusai, 'Mount Fuji seen through cherry blossom' (c.1834)

For all ‘Saturday volcano art’ articles: Saturday volcano art « The Volcanism Blog.

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Saturday Volcano Art: Hiroshige II, ‘Mount Asama’ (1859) 29 August 2009

Posted by admin in Asama, Japan, Saturday volcano art, volcano art, volcano culture.
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Hiroshige II, 'Mount Asama' (1859)

The artist known as Hiroshige II (1826-69) was a student of the great ukiyo-e artist Utagawa Hiroshige (1797-1858), who has already featured in this series. He became his master’s adopted son and married his daughter, Tatsu, and, after Hiroshige’s death in 1858, used his name; he had previously signed himself as Shigenobu. To avoid confusion, he is generally known as Hiroshige II. There is also a Hiroshige III, who was also the first Hiroshige’s adopted son and also married to Tatsu, but let’s not get into that here.

Mount Asama, the most active volcano on Honshu, is pictured in this image from Hiroshige II’s series One Hundred Views of Famous Places in the Provinces, published 1859-61. At the time this print was made the most recent significant eruption of Asama had occurred around 30 years earlier, in 1815, while in 1783 the volcano had produced one of the largest and most destructive eruptions (VEI=4) in modern Japanese history.

The print shows the volcano viewed from the south-east: on the left is the ridge of the Korufu-yama arc, remnant of an older volcano. The summit of Asama is producing brownish-grey emissions and is covered with recent ashfall and crowned with large boulders. The reddish-purple cloud, edged with yellow, that reaches across the distant ridge to encircle the volcano gives the scene a threatening air, emphasized by the towering flanks of the mountain (their steepness exaggerated by the artist) and the tiny, fragile details of the landscape in the foreground – trees, bushes, hurrying figures. There is a pervasive sense of unease that is absent from the first Hiroshige’s landscapes: a brooding atmosphere of latent threat. In this image the volcano is a grey monster, overshadowing the landscape and stirring in its sleep.

That sense of latent threat is by no means misleading. When this print was published Asama’s half-century of quiescence was coming to an end. In 1869 a VEI=2 event marked the beginning of a pattern of frequent eruptions (over fifty between 1875 and 2008) that has continued to the present day. Asama’s most recent eruption was in February 2009.

For all ‘Saturday volcano art’ articles: Saturday volcano art « The Volcanism Blog.

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Eruption at Sakura-jima 10 March 2009

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Sakura-jima 10 March 2009 (6)

The highly active stratovolcano Sakura-jima in southern Japan has erupted, say English-language news reports this morning. There are reports of an explosion at 05:22 local time, lava flows, an eruption column of up to 1.2km altitude, and volcanic debris projected to distances of up to 2km from the crater.

The Tokyo VAAC has issued a volcanic ash advisory for the volcano, but no aviation colour code alert has yet been issued. The Japan Meteorological Agency has issued a warning to local residents. The BBC has a video of the current activity.

My thanks to a Japanese reader of this blog who has sent some stills from videos of today’s eruption. One of these images is at the top of the post; click on ‘more’ to see the full series of six below.

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Saturday volcano art – Utagawa Hiroshige, ‘Miho no Matsuhara in Suruga Province’ (1858) 21 February 2009

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Utagawa Hiroshige, 'Miho no Matsubara in Suruga Province' (1858).

Utagawa Hiroshige (1797-1858), whose given name was Andō Tokutarō, was one of the masters of Japanese painting and print-making in the nineteenth century, one of the last great ukiyo-e artists and a leading exponent of the art of the full-colour landscape print. The son of a minor Shogunal official, he showed early promise in drawing and painting, and studied under a number of leading artists associated with the Utagawa school of the ukiyo-e genre, from which he took his professional name. In the first part of his career he produced prints in the characteristic ukiyo-e genre depicting beautiful women and actors, book illustrations and decorative works. In the 1830s he seems to have become aware of the possibilities offered by the then neglected genre of landscape, perhaps being inspired by the works being published by Katsushika Hokusai, including the celebrated Thirty-six Views of Mount Fuji (1830-33). Hiroshige began producing his own landscape print series, and with the publication from 1833 of Fifty-three Stages on the Tokaido he achieved success and his reputation was assured.

The beautifully symmetrical cone of Mount Fuji has long been a profoundly important symbol in Japanese culture, and images of Fuji form an ancient and rich tradition in Japanese visual art. With the development of Edo as the Shogunal capital after 1603 the ascetic religious cult of Mount Fuji became metropolitanized and absorbed into Court culture. During the seventeenth and eighteenth centuries Fuji was also highly active, making it even more of a powerful presence in the local landscape. The volcano, with its pilgrimage routes, its ascetic holy men and its shrines, became the focus of an increasingly popular urban religious movement during the Edo period, providing a market for visual representations of the volcano in prints, books and devotional images which an entire industry of artists, printmakers and publishers sought to fulfil. When first Hokusai and then Hiroshige (and their followers and imitators) began to produce innovative new styles of landscape prints in the first decades of the nineteenth century, Fuji was a natural choice of subject.

Hiroshige produced two woodblock print series of Fuji, both entitled Thirty-six Views of Mount Fuji, one in 1852 and another, at the very end of his life, in 1858 (although he produced many more images of the volcano throughout his career). The picture reproduced above is from the latter series and is typical of the artist’s later work in its simplicity, with the composition reduced to a limited number of motifs, and striking use of colour. Here the grey cone of the volcano stands starkly against a sky filled with a dramatic combination of yellow and black. The setting is a famous scenic location on Suruga Bay, on the Pacific coast of Honshu south-west of Tokyo, long celebrated for its views of Mount Fuji. Hiroshige emphasizes the dominance of Mount Fuji, but draws the surrounding scene of land and water, and the evidence of human activity in the boats that pass along the coast, into an overall harmony. This print represents the classic image of Fuji as the central motif of a landscape of elemental clarity and harmonious balance.

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