Detection of a crack‐like conduit beneath the active crater at Aso Volcano Japan

Yamamoto, Mare; Kawakatsu, Hitoshi; Kaneshima, Satoshi; Mori, Takehiko; Tsutsui, Tomoki; Sudo, Yasuaki; Morita, Yoshinori

doi:10.1029/1999gl005395

Cited by 77 publications

(77 citation statements)

References 7 publications

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“…Recent magnetotelluric surveys have detected a significantly low resistivity region at approximately 200 m below the crater lake. An analysis of the longperiod tremor indicated that volcanic fluid is transported to the region through a crack-like conduit (Yamamoto et al, 1999). These results suggest that a hydrothermal system exists at a shallow depth (Kanda et al, in press).…”

Section: Implication For the Volcanic Hydrothermal Systemmentioning

confidence: 85%

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Precise remote-monitoring technique of water volume and temperature of a crater lake in Aso volcano, Japan: implications for a sensitive window of a volcanic hydrothermal system

et al. 2008

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A high-resolution Digital Surface Model and a commercial digital camera have enabled precise and continuous monitoring of the crater lake at Aso volcano. From July 2006 onwards, infrared (IR) thermometry has been used with this system, enabling more accurate measurements of lake volume and temperature based on simple and intensive observations than has been possible in any other previous studies. The heat discharge remained largely constant at approximately 220 MW, with the exception of an abrupt increase to 280 MW that coincided with a rapid decrease in the water level in August 2007. Simultaneously, an increase in temperature at a shallow depth was suggested by other observations. The crater lake was found to respond to even slight changes in volcanic fluid supply, which can be well quantified by our method. Thus, a crater lake can be monitored more precisely than subaerial fumaroles whose energy estimation is often accompanied by large uncertainties. Our monitoring technique of a crater lake provides information on the subsurface hydrothermal system beneath it, for which any in-situ measurements are practically impossible.

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Section: Implication For the Volcanic Hydrothermal Systemmentioning

confidence: 85%

“…Various geophysical observational studies, including seismicity (Yamamoto et al, 1999) and geomagnetic field (Tanaka, 1993), have been carried out with the aim of determining the ascent processes of the volcanic fluid or magma at Aso volcano. These have revealed that the sources are located at shallow depths below Yudamari.…”

Section: Introductionmentioning

confidence: 99%

Precise remote-monitoring technique of water volume and temperature of a crater lake in Aso volcano, Japan: implications for a sensitive window of a volcanic hydrothermal system

et al. 2008

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“…Tsutsui et al (2003) observed a high-velocity zone considered to be a dike or dense volcanic deposits beneath Kusasenrigahama to the Nakadake crater; therefore, magma from a magma storage region could not ascended directly above this area. Yamamoto et al (1999) showed a dike model conduit beneath the Nakadake craters with a reasonable dip range of 83°-86°W. This dike probably has been created by connection faulting between Aso-N·C and Aso-S by westward dragging.…”

Section: Magma Plumbing System With Faultsmentioning

confidence: 99%

Effects of the 2016 Kumamoto earthquakes on the Aso volcanic edifice

Tajima

Hasenaka

Torii

2017

Earth Planets Space

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Large earthquakes occurred in the central part of Kumamoto Prefecture on April 14-16, 2016, causing severe damage to the northern segment of the Hinagu faults and the eastern segment of the Futagawa faults. Earthquake surface ruptures appeared along these faults and on the Aso volcanic edifice, which in turn generated landslides. We conducted landform change analysis of the central cones of Aso volcano by using satellite and aerial photographs. First, we categorized the topographical changes as surface scarps, arc-shaped cracks, and linear cracks. Field survey indicated that landslides caused the scarps and arc-shaped cracks, whereas faulting caused the linear cracks. We discovered a surface rupture concentration zone (RCZ) formed three ruptures bands with many surface ruptures and landslides extending from the west foot to the center of the Aso volcanic edifice. The magmatic volcanic vents that formed during the past 10,000 years are located along the north margin of the RCZ. Moreover, the distribution and dip of the core of rupture concentration zone correspond with the Nakadake craters. We conclude that a strong relationship exists between the volcanic vents and fault structures in the central cones of Aso volcano.

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“…The results from studies of volcanic tremors occurring at active volcanoes indicate that volcanic fluid or magma is related to the source mechanisms of the volcanic activity (e.g., Tameguri et al, 2007;Mori et al, 2008). Based on such results, it has been suggested that the source mechanisms of harmonic and long period tremors that have a resonant frequency are resonance phenomena occurring in the conduits or cracks filled with volcanic fluid or gas (e.g., Schlindwein et al, 1995;Yamamoto et al, 1999;Maryanto et al, 2008). However, the exact depth from the surface to the layer separating the vapor and liquid phases and to the magma head in a conduit cannot be obtained by geophysical prospecting or associated seismic observations.…”

Section: Introductionmentioning

confidence: 99%

Depth estimation of fumarolic gas source deduced by fume pressure measurement

Mori

Suzuki²,

Hirabayashi

et al. 2008

Earth Planet Sp

Self Cite

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The origin of fumarolic gas is hydrothermal boiling in the active fumarolic area and magma degassing in the active volcano where high temperature gas is discharged. The determination of the fumarolic gas source is important for understanding the geothermal activity or the eruption process. However, it is difficult to determine the gas source by geophysical prospecting using seismic or geomagnetic techniques due to the resolution limitation of these techniques. New measurement tools are therefore necessary. The aim of this study was to determine the conduit length-i.e., the depth of the fumarolic gas source-by measuring the fume pressure, which in turn facilitates the determination of the pressure oscillation of a conduit generated by acoustic resonance. We initially assembled the measuring device and measured the fume pressure at an active fumarole in Kusatsu-Shirane volcano, Japan. Our measuring device succeeded in measuring the pressure oscillation generated by acoustic resonance, revealing that the fumarolic gas source at Kusatsu-Shirane volcano has a depth of approximately 40 m. We propose that the use of an acoustic resonance is an effective approach for deducing the fumarolic gas source.

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Detection of a crack‐like conduit beneath the active crater at Aso Volcano Japan

Abstract: Abstract.To

Cited by 77 publications

References 7 publications

Precise remote-monitoring technique of water volume and temperature of a crater lake in Aso volcano, Japan: implications for a sensitive window of a volcanic hydrothermal system

Precise remote-monitoring technique of water volume and temperature of a crater lake in Aso volcano, Japan: implications for a sensitive window of a volcanic hydrothermal system

Effects of the 2016 Kumamoto earthquakes on the Aso volcanic edifice

Depth estimation of fumarolic gas source deduced by fume pressure measurement

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