Imaging the source region of the 2015 phreatic eruption at Owakudani, Hakone Volcano, Japan, using high‐density audio‐frequency magnetotellurics

2020 ◽  
Author(s):  
K. Seki ◽  
W. Kanda ◽  
K. Mannen ◽  
S. Takakura ◽  
T. Koyama ◽  
...  
Keyword(s):  
Source Region ◽  
Phreatic Eruption ◽  
High Density ◽  
Audio Frequency ◽  
Hakone Volcano

scholarly journals Analyzing the continuous volcanic tremors detected during the 2015 phreatic eruption of the Hakone volcano

2017 ◽  
Vol 69 (1) ◽  
Author(s):  
Yohei Yukutake ◽  
Ryou Honda ◽  
Masatake Harada ◽  
Ryosuke Doke ◽  
Tatsuhiko Saito ◽  
...  
Keyword(s):  
Phreatic Eruption ◽  
Hakone Volcano

scholarly journals InSAR analysis for detecting the route of hydrothermal fluid to the surface during the 2015 phreatic eruption of Hakone Volcano, Japan

2018 ◽  
Vol 70 (1) ◽  
Author(s):  
Ryosuke Doke ◽  
Masatake Harada ◽  
Kazutaka Mannen ◽  
Kazuhiro Itadera ◽  
Jun Takenaka
Keyword(s):  
Hydrothermal Fluid ◽  
Phreatic Eruption ◽  
Hakone Volcano

scholarly journals Precursory tilt changes associated with a phreatic eruption of the Hakone volcano and the corresponding source model

2018 ◽  
Vol 70 (1) ◽  
Author(s):  
Ryou Honda ◽  
Yohei Yukutake ◽  
Yuichi Morita ◽  
Shin’ichi Sakai ◽  
Kazuhiro Itadera ◽  
...  
Keyword(s):  
Source Model ◽  
Phreatic Eruption ◽  
Hakone Volcano ◽  
Precursory Tilt

scholarly journals Source constraints for the 2015 phreatic eruption of Hakone volcano, Japan, based on geological analysis and resistivity structure

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Kazutaka Mannen ◽  
Toshikazu Tanada ◽  
Akira Jomori ◽  
Takashi Akatsuka ◽  
George Kikugawa ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Phreatic Eruption ◽  
Mineral Precipitation ◽  
Hakone Volcano ◽  
Vapor Flux ◽  
Conductive Body ◽  
Before And After ◽  
Sealing Zone ◽  
Center Area ◽  
Geological Analysis

AbstractOn June 29, 2015, a small phreatic eruption occurred in the most intensively steaming area of Hakone volcano, Japan. A previous magnetotelluric survey for the whole volcano revealed that the eruption center area (ECA) was located near the apex of a bell-shaped conductive body (resistivity < 10 Ωm) beneath the volcano. We performed local, high-resolution magnetotelluric surveys focusing on the ECA before and after the eruption. The results from these, combined with our geological analysis of samples obtained from a steam well (500 m deep) in the ECA, revealed that the conductive body contained smectite. Beneath the ECA, however, the conductive body intercalated a very local resistive body located at a depth of approximately 150 m. This resistive body is considered a vapor pocket. For the 2 months prior to eruption, a highly localized uplift of the ECA had been observed via satellite InSAR. The calculated depth of the inflation source was coincident with that of the vapor pocket, implying that enhanced vapor flux during the precursory unrest increased the porosity and vapor content in the vapor pocket. In fact, our magnetotelluric survey indicated that the vapor pocket became inflated after the eruption. The layer overlaying the vapor pocket was characterized by the formation of various altered minerals, and mineral precipitation within the veins and cracks in the layer was considered to have formed a self-sealing zone. From the mineral assemblage, we conclude that the product of the 2015 eruption originated from the self-sealing zone. The 2015 eruption is thus considered a rupture of the vapor pocket only 150 m below the surface. Even though the eruption appeared to have been triggered by the formation of a considerably deeper crack, as implied by the ground deformation, no geothermal fluid or rocks from significantly deeper than 150 m were erupted.

Planar defects in ordered (Ga,In)P

1988 ◽  
Vol 46 ◽  
pp. 902-903
Author(s):  
S. McKernan ◽  
C. B. Carter ◽  
D. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Diffraction ◽  
Vapor Phase ◽  
Growth Direction ◽  
High Density ◽  
Ordered Structure ◽  
Planar Defects ◽  
Diffraction Patterns ◽  
Ternary Semiconductors ◽  
Anion Species ◽  
Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

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