Ulf Geomagneic Changes Associated with Crustal Activitity

Despite its extreme importance and years of effort, practical short-term earthquake prediction still remains to be achieved in future. However, earthquakerelated electromagnetic phenomena are recently considered as a promising candidate for short-term earthquake prediction. There have been accumulated a lot of evidences of precursory signatures in a wide frequency range (DC-VHF). The ULF geomagnetic change is one of the most promising phenomena and it suggests that the shortterm prediction is expected to realize. The methodologies to detect abnormal changes in ULF electromagnetic approach are described in this paper.