[SEM19-P06] Wideband MT survey in Aridagawa non-volcanic earthquake swarm region, Wakayama Prefecture
Keywords:Wideband MT survey, Aridagawa region, Wakayama Pref., non-volcanic earthquake swarm region
In 2015, we performed wideband MT survey at another profile across the Aridagawa area. Five component electromagnetic fields were measured at 5 sites by ADU-07 (Metronix Geophisics). We obtained continuous 1024Hz data, which were saved in the CF-memory once per an hour. After the survey, we made 32Hz and 1Hz data by downsampling. To avoid leakage current noise from the DC train (the Kisei main line), in analyzing the 1024 Hz data, we used only midnight data that was obtained from JST 2 to 5 a.m..
MT responses of a frequency band of 384-0.039Hz were estimated using remote reference method and the robust processing code BIRRP (Chave and Thomson, 2004). From the GB decomposition analysis (Chave and Smith, 1994, Toh and Uyeshima, 1997) and geological features, we considered that the optimum regional strike is in the EW direction. We tried to obtain a 2-D resistivity structure along N-S profile with the aid of the REBOCC 2-D inversion code (Siripunvaraporn and Egbert, 2000). In this presentation, we show the results of 2-D inversion and the relationship with the swarm activity.