Geomagnetic fluctuations and occurrence of Earthquake in Taiwan
Speaker: Chen Chun-Rong
Abstract
Taiwan has experienced many disastrous earthquakes in the past and can expect more in the future. Many examples of geomagnetic changes associated with earthquakes have been reported.The study of earthquake prediction to lessen or, at least better anticipate an earthquake hazard has become a more important research topic in Taiwan.For observing the geomagnetic field surrounding Taiwan, a network of eight geomagnetic stations was installed at the beginning of 1998 and extending into eleven stations at 2004. Chen et al. (2009) analyzed the data using the Chapman-Miller method for determining the parameters of the solar and lunar variations by four harmonics (Chapman and Miller 1940).It is clear from this study that the Chapman-Miller method can be employed to identify whether or not the geomagnetic field has been disturbed and also if magnetometersare functioning normally.Yen etal. (2004) has discover that somefluctuations during the Chi-Chiearthquake and Chia-Yi earthquake. Many other examples of geomagnetic changes associated with earthquakes have been reported.Note that before the large earthquake, the fluid expended or compressed in the crust results in the change of underground conductivity and current. These in turn modify the geomagnetic field around the coming earthquake area.These observations lead us to believe that these anomalous phenomena are connected to the process of accumulation and releases of crustal stress.
Reference
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