Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)

Directional drilling at Unzen Volcano in Japan during mid of 2004 penetrated the magma conduit and successfully recovered samples of the lava dike that is believed to have fed the 1991–1995 eruption. The dike was sampled about 1.3 km below the volcano’s summit vent and is intruded into a broader con...

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Main Authors: S. Nakada, K. Uto, S. Sakuma, J. C. Eichelberger, H. Shimizu
Format: Article
Language:English
Published: Copernicus Publications 2005-09-01
Series:Scientific Drilling
Online Access:http://www.sci-dril.net/1/18/2005/sd-1-18-2005.pdf
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author S. Nakada
K. Uto
S. Sakuma
J. C. Eichelberger
H. Shimizu
author_facet S. Nakada
K. Uto
S. Sakuma
J. C. Eichelberger
H. Shimizu
author_sort S. Nakada
collection DOAJ
description Directional drilling at Unzen Volcano in Japan during mid of 2004 penetrated the magma conduit and successfully recovered samples of the lava dike that is believed to have fed the 1991–1995 eruption. The dike was sampled about 1.3 km below the volcano’s summit vent and is intruded into a broader conduit zone that is 0.5 km wide. This zone consists of multiple older lava dikes and pyroclastic veins and has cooled to less than 200 ˚C. The lava dike sample was unexpectedly altered, suggesting that circulation of hydrothermal fluids rapidly cools the conduit region of even very active volcanoes. It is likely that seismic signals monitored prior to emergence of the lava dome reflected fracturing of the country rocks, caused by veining as volatiles escaped predominantly upward, not outward, from the rising magma. Geophysical and geological investigation of cuttings and core samples from the conduit and of bore-hole logging data continues. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.3.01.2006" target="_blank">10.2204/iodp.sd.3.01.2006</a>
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spelling doaj.art-7475697e79d848fba1eba3db3c3ddc202022-12-22T01:06:08ZengCopernicus PublicationsScientific Drilling1816-89571816-34592005-09-011182210.5194/sd-1-18-2005Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)S. Nakada0K. Uto1S. Sakuma2J. C. Eichelberger3H. Shimizu4Earthquake Research Institute, University of Tokyo, Yayoi, Bunkyo, Tokyo 113-0032, JapanAEST Geological Survey of Japan, Geol. Surv. Japan, AIST, Higashi, Tsukuba 305-8567, JapanJapan Metals and Chemicals Co. Ltd., Takizawa, Iwate 020-0172, JapanGeophysical Institute, University of Alaska, Fairbanks, AK 99775, USAInstitute of Seismology and Volcanology, Kyushu University, Shinyama, Shimabara 855-0843, JapanDirectional drilling at Unzen Volcano in Japan during mid of 2004 penetrated the magma conduit and successfully recovered samples of the lava dike that is believed to have fed the 1991–1995 eruption. The dike was sampled about 1.3 km below the volcano’s summit vent and is intruded into a broader conduit zone that is 0.5 km wide. This zone consists of multiple older lava dikes and pyroclastic veins and has cooled to less than 200 ˚C. The lava dike sample was unexpectedly altered, suggesting that circulation of hydrothermal fluids rapidly cools the conduit region of even very active volcanoes. It is likely that seismic signals monitored prior to emergence of the lava dome reflected fracturing of the country rocks, caused by veining as volatiles escaped predominantly upward, not outward, from the rising magma. Geophysical and geological investigation of cuttings and core samples from the conduit and of bore-hole logging data continues. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.3.01.2006" target="_blank">10.2204/iodp.sd.3.01.2006</a>http://www.sci-dril.net/1/18/2005/sd-1-18-2005.pdf
spellingShingle S. Nakada
K. Uto
S. Sakuma
J. C. Eichelberger
H. Shimizu
Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)
Scientific Drilling
title Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)
title_full Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)
title_fullStr Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)
title_full_unstemmed Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)
title_short Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)
title_sort scientific results of conduit drilling in the unzen scientific drilling project usdp
url http://www.sci-dril.net/1/18/2005/sd-1-18-2005.pdf
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