By comparing seismic data from over one thousand earthquakes across the globe with quantum mechanical models for the properties of iron, they suggest that seismic variations directly reflect variations in the iron structure.
To interpret co-seismic variations in magnetic fields in terms of the piezomagnetic effect, however, theories should be reconsidered in a framework of elastodynamics.
Simulations of co-seismic variations in the piezomagnetic field are additionally complicated by the fact that they involve 3-D volume integrals, even if the magnetization structure itself is two-dimensional.
Therefore, it is concluded that the piezomagnetic effect may be a plausible mechanism of co-seismic variations in the geomagnetic field in certain settings, particularly if the magnetometer is installed near magnetization boundaries.
In the case that co-seismic variations are observed only in the magnetic field (e.g., Okubo et al., 2009), the contribution of the piezomagnetic effect must be taken into account because the electrokinetic effect and electromagnetic induction primarily generate electrical fields.
Furthermore, the seismic response variation is evaluated parametrically to investigate the effect of connection parameter spatial variability.
To reduce computation demands in calculating the seismic response variation, design parameters that have a negligible effect on seismic response are first eliminated through sensitivity analysis.
Seismic velocity variation in carbonate rocks is a complicated function of different parameters such as mineral composition, porosity, pore type, saturation, and pore pressure.
We have revealed the along-trench seismic structure variation within the overlying plate by wide-angle seismic traveltime analysis.
For the purpose of testing for a possible seismic moment variation at very long periods, we performed additional W phase inversions using increasingly long period band pass filters.
These empirical equations are useful for estimating the average characteristics of seismic amplitude variation with hypocentral distance; however, the observed ground motions (e.g., peak ground velocity) show large scatter around the predictions (e.g., Strasser et al. 2009).
