Research on Seismo-Electromagnetic Precursors of Earthquake -- New geomagnetic network of Taiwan

In Taiwan, fluctuation in the geomagnetic field associated with change in tectonic stress is identified as one facet of the ­Research on Seismo-Electromagnetic Precursors of Earthquake­" program. A new geomagnetic network of twelve stations equipped with continuous recording systems will be completed before June 2003 by the Institute of Geophysics, National Central University. All stations are location in areas of high seismicity or crustal activity except the Kinmen station. The geomagnetic observation station on Kinmen Island will be a reference station in this network. The accuracy of the instruments will be 0.1 nT, the sampling rate is at 1 minute interval, and apart from being stored in the hard disks of the observation instruments, the geomagnetic data recorded will be relayed back to the National Central University Data center by way of telephone lines daily. In order to detect changes in geomagnetic field associated with tectonic stress, it is necessary to eliminate the changes originating from external sources in the observed data. A simple way is by using the differences of geomagnetic data between field stations and the reference station. The goals of this network will investigate the temporal geomagnetic variations, as well as their associated with earthquake occurrences and changes in tectonic stress.