+++ ICDP: Call for Proposals - Next Chance January 15, 2018 +++ Highlights and Updates Moved to the new ICDP Web Site +++

Unzen Scientific Drilling Project



Unzen VolcanoUnzen Volcano was nominated as one of the Decade Volcanoes of the United Nation's Decade of Natural Disaster Reduction, since it represents an important type of dangerous volcano. 

The volcanic eruptions at Unzen (Japan) during 1990-1995 took a heavy toll on life and property through devastating pyroclastic flow events. In order to understand the structure and growth history of the volcano and to clarify the eruption mechanisms of SiO2-rich viscous magmas, the Unzen Scientific Drilling Project (USDP), a six-year project consisting of two phases, was started in April 1999. In the first phase, two holes were drilled into the volcano's flank (USDP-1 and -2). In the second phase, drilling penetrated the magma conduit that fed a lava dome at the summit. The detailed design and targets of the conduit drilling were determined in the first phase.
The magma conduit, especially its upper part, is believed to be the site of effective degassing that is the major factor controlling eruption styles. The pressure-dependent nature of solubility of volatiles, principally water, accelerates vesiculation as magma approaches the service and produces geophysical signals (earthquakes and inflation) in the shallow conduit region. Drilling into this region will allow for the first in situ observations and sampling of the still-hot conduit and wall rocks of a recent, well-observed eruption.

(Photo ©:Ronald Conze OSG/ICDP)



Asia, Japan, Kyushu, Nagasaki Province, Shimabara Peninsula, Unzen Volcano



32° 46' 11'' N, 130° 17' 11'' E (Please scroll down to end of page for more information.)


Project Start and End
  • Phase I 
    • Begin of drilling February 17, 2003
    • End of drilling November 13, 2003
  • Phase II 
    • Begin of drilling May 13, 2004
    • End of drilling July 7, 2004


Programs and Funding


Principal Investigators
  • Setsuya Nakada, University of Tokyo, Earthquake Research Institute, Volcano Research Center
  • Kozo Uto, National Institute of Advanced Industrial Science and Technology, Institute of Geology and Geoinformation, Magmatic Activity Research Group
  • John C. Eichelberger, U.S. Geological Survey at Reston, Volcano Hazards Program
  • John C. Eichelberger, University of Alaska at Fairbanks, Graduate School
  • Hiroshi Shimizu, Kyushu University, Shimabara Earthquake and Volcano Observatory
  • Sumio Sakuma, Japan Metals and Chemicals Co. Ltd., Geothermal Division


Partners and Contractors



Active Volcano, Conduit, Directional Drilling, Explosion, Hazards, ICDP-2001/01, Japan, Kyushu, Shimabara, Thermal Regimes, UNZEN, USDP, Volcanic Systems


Current State





    Google Earth/Maps