for unveiling a possible relationship between geomagnetic field variations and Earth’s orbital parameters were conducted. Studies of absolute paleointensity for volcanic rocks have also progressed: the average field intensity for the past ca. 5 Ma as well as intensity variations over transient periods, such as polarity transitions and geomagnetic excursions, were examined on the basis of a modified version of the Shaw method.
Oceanic and continental drillings have provided unique opportunities for obtaining materials for various types of paleomagnetic research. The Integrated Ocean Drilling Program (IODP) began in October 2003. A number of paleomagnetists have been involved in the expeditions. A riser-drilling vessel “Chikyu,” constructed for IODP, will embark on scientific drillings in October 2007.
As for extraterrestrial magnetism, the lunar exploration mission SELENE is scheduled to be in orbit in the summer of 2007. The remnant of the magnetic field of the Moon will be measured, which will enable us to unveil its ancient (3 to 4 billion years ago) magnetic field.
2.2 Electromagnetic studies of the Earth’s interior The collection and distribution of geomagnetic and geoelectric data from the Ocean Hemisphere Project (OHP) resulted in three-dimensional electrical conductivity models of the mid-mantle in the
Pacific and Europe.
These are the first models comparable to
the ones from seismic tomography, The OHP was succeeded by a new
multi-disciplinary, five-year project designed to reveal “a stagnant slab” in the mantle transition zone.
Efforts continued to promote major projects to identify basic electromagnetic properties on a regional scale. For example, the network MT project has further been carried out, compiling distributions of the
electrical conductivity of the crust and upper mantle.
An attempt to establish a regional
reference field generated a few preliminary models for the region in and around Japan.
Intensive studies in tectonically active environments were also made especially by magnetotelluric and aeromagnetic survey to explore the distribution of fluids in the crust and their roles in the
surveys on volcanoes became possible
volcanic studies, a quantitative interpretation of self potential by elaborated laboratory experiments of the zeta potential.
3. Meetings, Reorganizations, and Research Programs
The XIth IAGA Workshop on Geomagnetic Observatory Instruments, Data Acquisition and Processing was held at the Kakioka Magnetic Observatory and Tsukuba City on November 9-17, 2004. After four-years of extensive discussions, a report from this National Committee in the Science Council of Japan, entitled “Geomagnetism and Aeronomy in the 21st Century” was published in August 2004. It
recommends several major research projects the national universities and some national institutions
Japanese have been
science community should initiate. All reorganized, making their management to
be more independent from the government. May 2005 and our society, i.e., Society of
The Japan Geoscience Union (JPGU) was established in Geomagnetism and Earth, Planetary and Space Sciences,
became one of its members.
The Japanese organization for IHY, recognized by the United Nations, was
established in 2006, and four international projects, i.e., MAGDAS Project, Muon Detection Network, IPS Network, and Network of International Space Environment Service, have joined the IHY program. The Japanese eGY (electronic Geophysical Year) Committee was established in 2005 and the eGY Subcommittee in the Science Council of Japan was established in January 2007.