Convenors

Yoichi Sasai   Disaster Prevention Division   Tokyo Metropolitan Government   Tokyo   Japan   Email: yosasai@zag.att.jp Jacques Zlotnicki   OPGC-CNRS   France   Email: jacques.zlotnicki@wanadoo.fr

Description

ElectroMagnetic (EM) fields are particularly sensitive to rather shallower parts of a volcano because of their penetration depth. They often manifest anomalous changes simultaneously with geochemistry, temperature and potential field signals. EM observations are mainly based on the detection of signals in 1. the geomagnetic field, 2. the electrical resistivity, 3. the self electric potential (SP) and 4. the EM emissions. Volcanic eruptions generate various kinds of EM signals, from the ground to the ionosphere, which can also be detected by satellites as GPS-TEC or DEMETER observations. Combined EM methods turn into a very powerful tool for volcano monitoring when other geochemical and geophysical observations are associated. Also, EM methods can be effective for monitoring phreatic explosions, which sometimes show no mechanical forerunners. This session will focus on a. Volcano structure as revealed by combined EM and other geophysical methods, b. Geochemistry and thermal budget of sources for volcano-EM signals, c. Joint EM, geochemical and geophysical observations, d. Joint modelling of EM and other geophysical data, e. Advanced technologies for time series analyses of EM signals, f. EM and other signals related to phreatic and phreato-magmatic explosions, g. Satellite and other remote sensing of EM signals related to volcanic activities, h. EM emissions related to volcanic eruptions and pyroclastic flows, and i. Mapping volcanic hazards by EM, geochemical and geophysical methods.