Table 2 Amount and rate of changes in ground surface elevation for each period
Period | I | II | III | IV |
|---|---|---|---|---|
Year | 2004–2011 | 2011–2013 | 2013–2014 | 2014–2015 |
Duration (months) | 85 | 30 | 12 | 12 |
Strong earthquakes and maximum acceleration | 2004 Chuetsu (17.5 cm/s2) 2007 Chuetsu-oki (3.02 cm/s2) 2011 N Nagano (3.08 cm/s2) |  | 2014 Kamishiro (0.22 cm/s2) |  |
Mean elevation change (mm) | 44.1 | 4.7 | 0.2 | 11.6 |
Standard deviation of elevation change (mm) | 128.4 | 19.8 | 19.0 | 12.8 |
1st percentile | −222.5 | −34.8 | −46.3 | −19.5 |
99th percentile | 397.5 | 59.7 | 30.0 | 30.0 |
Mean rate of elevation change (mm/year) | 6.2 | 1.9 | 0.2 | 11.7 |