Active Geophysical Monitoring

CHAPTER 25

CHARACTERISTICS OF ACROSS SIGNALSTRANSMITTED FROM THE TONOTRANSMITTING STATION AND OBSERVEDBY HI-NET

Yasuhiro Yoshida^a, Hiroshi Ueno^b, Satoshi Takahama^b,Yuzo Ishikawa^c, Sumio Yoshikawa^b, Akio Katsumata^a,Takahiro Kunitomo^d, and Mineo Kumazawa^d

Contents

1. Introduction

2. Data and Methods

3. Results

4. Discussion

5. Conclusion and Future Plan

Acknowledgments

References

1. INTRODUCTION

The validity of using ACROSS signals for detecting temporal variations in P- and S-wave travel times over short distances (less than several kilometers) has been confirmed by previous studies. Ikuta et al. (2002) detected an S-wave delay of about 1 ms after the 2000 Western Tottori earthquake (Mw 6.6) using ACROSS deployed at Awaji Island. The ACROSS signals ...