The 1997 phreatic eruption of Akita-Yakeyama volcano, northeast Japan: Insight into the hydrothermal processes

Nogami, Keiji; Hirabayashi, Jun-ichi; Ohba, Takayoshi; Yoshiike, Yuzo

doi:10.1186/bf03351631

Cited by 10 publications

(6 citation statements)

References 11 publications

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“…Ollier, 1967; table in Kienle et al, 1980); we follow Lorenz (1973) in restricting maar volcanoes to those formed by eruptions of magma, though juvenile fragments may form only a small proportion of total ejecta. Hydrothermal explosion pits have different physical origins (Muffler et al, 1971;Nairn and Wiradiradga, 1980;Nogami et al, 2000;Browne and Lawless, 2001), and are not discussed here. Maar volcanoes have formed in a great diversity of subaerial volcanic settings, from magmas with a wide range of compositions (Lorenz, 2007).…”

Section: Small Volcanoesmentioning

confidence: 99%

Maar-diatreme volcanoes: A review

White

Ross

2011

Journal of Volcanology and Geothermal Research

345

251

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Maar-diatreme volcanoes are produced by explosive eruptions that cut deeply into the country rock. A maar is the crater cut into the ground and surrounded by an ejecta ring, while the diatreme structure continues downward and encloses diatreme and root zone deposits. Here we attempt an evenhanded review of maardiatreme volcanology that extends from mafic to kimberlitic varieties, and from historical maar eruptions to deeply eroded or mined diatreme structures. We conclude that maar-diatreme eruptions are episodic. Ejecta rings provide invaluable insight into eruption processes and sequence, but are incomplete records of diatreme formation. Deposits within the diatreme structure include, in varying proportions, lower unbedded deposits sometimes typified by subvertical contacts among domains of debris emplaced sequentially, and upper bedded deposits formed by sedimentation on surfaces open to the atmosphere. A basal root zone comprises the transition from coherent magmatic feeder dike to clastic deposits formed by fragmentation of magma and enclosing country rock; root zones are irregular in form, and the clastic deposits are typically intruded by contorted dikes. Irregular root zone-like chaotic breccias cut by contorted dikes are also present within diatreme deposits, where they represent intra-diatreme fragmentation zones and record changes in the location of the explosion locus during eruption.

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Section: Small Volcanoesmentioning

confidence: 99%

Maar-diatreme volcanoes: A review

White

Ross

2011

Journal of Volcanology and Geothermal Research

345

251

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“…Monitoring volcanic gases can provide information on subsurface conditions and continual observation of volcanic gases will contribute towards the prediction of eruptions (e.g. Hirabayashi et al, 1999;Nogami et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…It is a kind of remote monitoring method which is available for observation of volcanic activity (e.g. Taylor and Stoiber, 1973;Ossaka and Ozawa, 1975;Ossaka et al, 1998;Nogami et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Temporal variations in the constituents of volcanic ash and adherent water-soluble components in the Unzen Fugendake eruption during 1990–1991

et al. 2014

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A change in the chemical compositions of volcanic gases is one of the noticeable phenomena that frequently occurs prior to an eruption. Analysis of the water-soluble components adhering to volcanic ash is available for remote monitoring of volcanic gases from inaccessible volcanoes. It is a secure method for monitoring volcanic activity without using particular devices. Prolonged volcanic eruption at the Unzen Fugendake volcano from 1990 to 1995 started with a phreatic eruption after 198 years of dormancy. Volcanic activity changed from a phreatic and phreatomagmatic eruption to a magmatic eruption with pyroclastic flows in May 1991. The relationship between the chemical composition of volcanic ash and the contents of the water-soluble components adhering to it are discussed in relation to the early stage of the long-term eruption. Volcanic ash ejected by phreatic and phreatomagmatic eruption before dome formation was the product of the alteration in the volcanoclastic materials beneath the surface. The ash had a high content of water-soluble components, which was caused by the absorption of hydrogen chloride and sulfur dioxide gases from magma into wet debris before dome formation. Volcanic ashes which were generated by pyroclastic flows after dome formation were fresh lava fragments. While the contents of water-soluble sulfate adhering to the ash noticeably decreased, those of water-soluble chloride adhering to the ash hardly decreased. The considerable decrease in the contents of water-soluble sulfate was caused by the reaction of volcanic gases with dry lava fragments. Contrary to this, the concentration of hydrogen chloride gas in ash clouds was extremely high, which obstructed the decrease in the water-soluble chloride content in the ash. Volatility of chlorine and sulfur from volcanic rock suggests that the inner temperature of pyroclastic flows was higher than 600∼700 • C at least.

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“…Changes in the chemical composition of gases and/or hot springs may refl ect an interaction more or less important between the deep fl uid and the superfi cial aquifer (Ohsawa, 1993;Valentino, 1999;and Tassi, 2003). But, these evolutions may also be the consequence of an increase in the volcano activity that could generate a phreatic eruption (Nogami, 2000), or a magmatic one (Giggenbach, 1990;Takano and Watanuki, 1990;Arribas, 1995;and Fischer, 1997). The recent activity ejected ash and altered rocks coming from the inside of the hydrothermal system offers an opportunity to improve our knowledge on the alteration processes occurring at depth (Christenson and Wood, 1993).…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal system of the Papandayan Volcano, West Java, Indonesia and its geochemistry evolution of thermal water after the November 2002 eruption

MAZOT¹

2006

IJOG

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Papandayan is a strato volcano situated in West Java, Indonesia. After the last magmatic eruption in 1772, only few phreatic explosions have been occurring. At the present time, the activity is centered in the northeast crater manifested by the presence of fumaroles and hot springs. In November 2002 an explosive eruption occurred and ejected ash and altered rocks. Study of the altered rocks revealed that an advanced argillic alteration took place in the hydrothermal system by an interaction between acid fl uids and rocks. Four zones of alteration have been formed as a limited extension along faults or across permeable structures at different levels beneath the active crater of the volcano. Two types of acid fl uids are distinguished in the crater of the Papandayan Volcano: (1) acid sulphate-chloride water with pH values between 1.6 and 4.6, and (2) acid sulphate water with pH values between 1.2 and 2.5. The samples collected after the eruption revealed an increase in the SO 4 / Cl and Mg / Cl ratios. This evolution is likely explained by an increase in the neutralization of acid fl uids which tends to show that water-rock interactions were more signifi cant after the eruption. The changes in chemistry observed in 2003 were the consequence of the opening of new fractures where unaltered or less altered volcanic rocks were in contact with the ascending acid water. The high δ 34 S values (9-17‰) observed in the acid sulphate-chloride water before the November 2002 eruption suggest that dissolved sulphates were mainly formed by the disproportionation of magmatic SO 2. On the other hand, the low δ 34 S values (-0.3-7 ‰) observed in acid sulphate-chloride water sampled after the eruption suggest that the origin of dissolved sulphates for these waters is the surfi cial oxidation of hydrogen sulphide.

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The 1997 phreatic eruption of Akita-Yakeyama volcano, northeast Japan: Insight into the hydrothermal processes

Cited by 10 publications

References 11 publications

Maar-diatreme volcanoes: A review

Maar-diatreme volcanoes: A review

Temporal variations in the constituents of volcanic ash and adherent water-soluble components in the Unzen Fugendake eruption during 1990–1991

Hydrothermal system of the Papandayan Volcano, West Java, Indonesia and its geochemistry evolution of thermal water after the November 2002 eruption

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