Seismological and Volcanological Research Department
Meteorological Research Institute
1-1 Nagamine, Tsukuba-shi, Ibaraki-ken 305-0052
Japan

Kakioka Magnetic Observatory
Kakioka 595, Yasato-machi, Niihari-gun, Ibaraki-ken 315-0116
Japan

Staff :
           Mr. Masaaki Churei - Director
           26 staff members

There are currently a total of 108 active volcanoes in Japan. Eruption or abnormal phenomena are observed approximately at 10 volcanoes a year on average, sometimes causing great disasters. The Japan Meteorological Agency has defined active volcanoes in Japan as "volcanoes which have erupted within 10,000 years or volcanoes with vigorous fumarolic activity".

The Japan Meteorological Agency (JMA) monitors 26 active volcanoes day and night with seismometers and other equipments and also less active volcanoes by sending mobile observation teams during their emergency.

When volcanoes become restless, JMA issues volcano information.

JMA has been making a concerted effort to predict volcanic eruption in accordance with the Volcanic Eruption Prediction Program while accumulating data, building up expertise and promoting relevant research. As volcanic phenomena are very complicated, Meteorological Research Institute and Kakioka Magnetic Observatory mentioned below are engaged in research and development activities related to volcanic eruption process.

Organization of JMA:

JMA consists of headquarters, field offices, and auxiliary organs. The headquarters is in the heart of Tokyo, made up of five Departments which are responsible for administering and planning of respective tasks: forecasts; observations; earthquakes and volcanoes; climate and marine affairs; and administration which deals such matters as overall planning, aviation meteorology, commercial meteorology, finance, personnel. Some of the Divisions under these Departments also function as a national or a regional operational center for specific tasks --- conducting numerical weather predictions, issuing forecasts or directing local forecast services, issuing maritime forecast, and monitoring earthquakes and forecasting tsunamis.

There are six District Meteorological Observatories including Okinawa in the respective areas. These Observatories lead smaller field offices such as Local Meteorological Observatories and Weather Stations; they also operate as regional centers for directing regional forecast, monitoring regional earthquakes, tsunamis, and volcanoes. There is at least one Meteorological Observatory in a prefecture. These Observatories work as a contact point for local authorities and regional disaster-prevention organizations representing JMA.

In addition, there are four Marine Observatories operating individual maritime meteorological observation vessels. These Observatories work not only for marine and maritime meteorological observation but also for regional weather services in each area.

OBSERVATION REGIME OF JMA

The JMA constantly conducts seismic and infrasonic observations, ground deformation observation, visual observation and other observations at 25 active volcanoes. Volcano Observation and Information Centers (VOIC) were established in the Headquarters in Tokyo and Sapporo, Sendai and Fukuoka District Meteorological Observatories in 2001. The data obtained at each site are telemetered to the relevant VOICs. Based on the observation results, VOICs release volcano information which is conveyed to the general public through various channels.

Seismic observation is conducted to observe volcanic earthquakes and tremors. The JMA is analyzing the sources and wave forms of them to investigate the state of volcanoes.

In a volcano area, change of ground tilt, and expansion and contraction are produced in accordance with magmatic activity. Ground deformation observation monitors underground activity by observing those diastrophism by the tiltmeter and GPS which are installed around volcano.

A visual observation is to observe height and color of plume, erupted materials (ash fall, volcanic bombs, etc.)and other volcanic phenomena from a fixed point. In Volcanic Observations and Information Center, volcanoes are continuously monitored with the volcano visual observation equipment (a high sensitivity camera, or visible and infrared camera)

Infrasonic waves are excited by an atmospheric pressure change by eruption or explosion, and are utilized in order to detect an eruption or to evaluate its magnitude. Infrasonic waves are observed with low frequency microphones that were installed at volcanoes.

Volcanic Observations and Information Center dispatches a mobile observation team in order to monitor the state of the volcanic activity. Mobile observation is carried out periodically or emergently.

With infrared thermal image equipment, the high temperature region of the fumarole circumference is caught in situ. The change of volcanic activity is monitored by observing the state of the far-reaching thermal activity.
By observing change of the composition ratio or the amount of discharge of various volcanic gas, the underground state and underground volcanic activity of magma are investigated.
In the comparatively narrow domain around activity region, GPS observation equipment is installed in the fixed point, and the state of volcanic activity is monitored by observing ground deformation in a local area.
Activity of the magma inside a volcano changes the value of the geomagnetism near the volcano. To observe the change of such geomagnetism, the thermal state inside a volcano is monitored.
In a place where approach is difficult because of volcanic activity or other reason, various obser- vation for monitoring volcanic activity is performed using an un-maned remote control helicopter and Kite with engine as a means to observe without infringing on danger.

• Seis = Seismic Observation
• TV = Visual Observation with TV camera
• GPS = GPS Observation
• Infr = Infrasonic Observation
• Tilt = Tiltmeter Observation
• EDM = EDM Observation
• Mag = Geomagmetic Observation
• Gas = Gas density Observation

Staff :
           Mr. Masami Sakurada - Supervisor
           4 staff members

The Tokyo VAAC is responsible for monitoring volcanic ash clouds in the East Asia and the Northwest Pacific region and issuing Volcanic Ash Advisories (VAAs) .

Monitoring of volcanic ash clouds

Tokyo VAAC receives information on volcanic activities from JMA volcano observations and information centers, other oversea volcano obervatories.
Pilot reports on volcanic eruptions from cruising airplanes and satellite images from the geostationary meteorological satellite (GOES-9) and polar orbiting satellite (NOAA) are also important information sources.

Issuance of the Volcanic Ash Advisory (VAA)

VAACs issue Volcanic Ash Advisories (VAAs), which describe the latest extent and forecast trajectories of volcanic ash clouds in both text and graphical formats defined in ICAO Annex 3, to assist MWOs in preparing SIGMETs on volcanic ash clouds. VAA is updated basically every 6 hours (00, 06, 12, and 18 UTC) as long as ash clouds are identified by satellite imagery. If remarkable changes occur in the ash clouds, VAA is updated at any time. In case that the extent of volcanic ash clouds are recognized on satellite imageries, the volcanic ash graphic information and the volcanic ash dispersion forecast charts are issued as well.VAAs are disseminated to twenty-four MWOs and eight VAACs and are also provided to the offices of the Civil Aviation Bureau and airline companies in Japan through the airport branches of JMA. :

Staff :
           Dr. Nobuo Hamada - Director
           18 staff members (including seismological research staffs)

The Meteorological Research Institute (MRI) is an auxiliary organ of JMA, and supports the works of JMA by research activities on meteorological and geophysical phenomena. In the Seismology and Volcanology Research Department of MRI researchers make studies of earthquake, tsunami, volcanic activity and instruments to observe these phenomena, to contribute to the seismic and volcanic monitoring of JMA. Temporary observations (GPS, tilt, EDM, magnetic field and others) are carried out in several volcanoes for the volcanological research.

List of observations in volcano carried out by MRI

Staff :
           Mr. Masami Okada - Director
           44 staff members (including management and other research staffs than volcanologists)

The Kakioka Magnetic Observatory is in charge of geomagnetic and geoelectric observations and the relevant researches as one of auxiliary organs of JMA, and carries out research activities also for monitoring of volcanic activities.

1. Development of electromagnetic observing techniques for volcanic monitoring

Magnetic field observation in a volcanic area faces many difficulties, because of its severe surrounding environment. Development of observation techniques to obtain more stable and accurate magnetic field data by more efficient ways in volcanic areas is one of the missions of the Kakioka Magnetic Observatory.

2. Development of techniques for analyzing magnetic data and for evaluating volcanic activities

Magnetic fields around a volcano slightly change in accordance with volcanic activities. However, they also change with a dynamo process in the Earth's core, solar-terrestrial interactions, sea currents and artificial noises. Another mission of the Magnetic Observatory is to sophisticate analyzing techniques to pick out signals due to volcanic activities from observed data and to utilize them for physical understanding of volcanic activities as follows:

- development of techniques to pick out signals from volcanic activities,
- development of modeling methods for the magnetic field variation caused by complicated distribution of thermal sources as shown in the figure below,
- development of synthesized software to analyze volcanic activities.