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...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2005-09-01
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| Series: | Scientific Drilling |
| Online Access: | http://www.sci-dril.net/1/18/2005/sd-1-18-2005.pdf |
| Summary: | 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.
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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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| ISSN: | 1816-8957 1816-3459 |