Active Geophysical Monitoring

CHAPTER 14

SIGNAL DISCRIMINATION OF EXTERNAL GEOMAGNETIC EFFECTS USING THE TRANSFER FUNCTION APPROACH WITH CONTINUOUS WAVELET TRANSFORM

Makoto Harada^a, Katsumi Hattori^b, and Nobuhiro Isezaki^b,a

Contents

1. Introduction

2. Formulation of Signal Discrimination

2.1. Interstation transfer function (ISTF)

2.2. ISTF approach to the magnetotelluric (MT) response function

2.3. Elimination of the external geomagnetic effects

3. Application of the Wavelet Transform

3.1. Continuous wavelet transform

3.2. Auto- and cross-correlation functions based on the wavelet transform

3.3. Wavelet-based transfer function and correlation function

4. Application to Observed Data

5. Verification of the Detectability of Artificial Signals

6. Conclusion

References

1. I