[M-IS04] Interdisciplinary studies on pre-earthquake processes

[MIS04-P09] Development of a detection method for magnetic field anomalies related to earthquakes with the use of Interstation Transfer Function Method

*WANG JINGYU¹, Shu Kaneko¹, Wenchao Li¹, Yoichi NODA¹, Chie Yoshino², Katsumi Hattori² (1. Graduate School of Science and Engineering, Chiba University, 2.Graduate School of Science, Chiba University)

Keywords:ULF , interstation transfer function method, seismo-electromagnetics, magnetic field anomalies

There are many reports on seismo-electromagnetics. Among of them ULF magnetic field change is one of the most promising approaches. The observed ULF signals are superposition of some signals. The most intense signal is the global one, so-called geomagnetic pulsations, the second one is signals related to artificial noises, such as DC driven train noises and factory noises, and the weakest one is related to the signals from underground including seism-electromagnetic phenomena. To study the seismic electromagnetic signals, the discrimination of the observed signals is important. Until now many methodologies have been developed. Nighttime energy of the vertical component observed at Kakioka, Japan is investigated in statistically. In this report, they use the ratio between the data at Kakioka and reference station to remove the global effect. In this study, we try to remove the global effect using Inter Station Transfer function (ISTF) approach. We analyze the Kakioka data with Memambetsu and Kanoya data as reference data, we analyze the ISTF between Kakioka and Kanoya and between Kakioka and Memambetsu for 2001-2010. In this presentation, we will demonstrate the stability of ISTF and performance of global signal reduction. The nighttime energy changes at Kakioka and reference stations will be also given, the details will be shown in our presentation.