[SGD03-P03] Characteristics of the Tenryu-Funagira laser extensometer and its detection ability of slow slips
Keywords:Laser extensometer, iodine-stabilized laser, slow-slip observation
We compared the obtained data with that previously obtained with He-Ne laser. It was found that the atmospheric pressure response and tidal response were not changed. However, trend was changed. Trend of about 10-7 strain/year was previously observed. No such trend is observed currently. A trend change was observed before and after the 2011 Tohoku earthquake. The trend might be affected by local condition. We compared spectrum levels of the detrended previous and current data. The spectrum level was almost the same over a period range from 0.1 s to several months.
Ide et al. (2007) presented a scaling law of slow earthquakes, in which seismic moment is proportional to event duration. It is considered that strain rate would be the same level regardless of its seismic moment based on the scaling law. Katsumata et al. (2001) showed that the Tenry-Funagira laser extensometer would detect strain change with strain rate the same as those of short-term slow-slips in a day. If there were a slow-slip of one day duration, the Tenryu-Funagira laser extensometer could detect it.