We have conducted a case study for recently proposed parameter of non-linear site response DNLs. The data are used the accelerograms of the 2011 off the Pacific coast of Tohoku earthquake and its aftershocks, mainly, recorded at three KiK-Net stations that have vertical arrays.
Besides DNLs PGA amplification is considered as a reference parameter. In FKSH14 and IBRH13, a significant de-amplification is observed in the range of PGA at the borehole bottom greater than 10 gals; also in the range of PGA at the ground surface greater than 100 gals, whereas in IBRH18, it is not observed with the only exception, i.e., the main shock. It is observed that DNLs increases with the PGA both at the ground surface and borehole bottom in the range as mentioned above for all three stations. DNL based on the horizontal to vertical spectral ratio of the surface record (DNLS-H/V) well follows the behavior of that based on the spectral ratio of the surface records to those obtained at the borehole bottom (DNLSB) and shows a possibility to use the former in place of the latter if only surface records are available. We may expect that these DNLs will be useful for the future strong motion study in Myanmar.