“…For a quantitative study on ageing, Leon et al (2006) discussed the timescale of thousands of years or more on the basis of a small number of available data. Yoshimi et al (1984), Goto (1995), Goto et al (1987Goto et al ( , 1992, Hatanaka et al (1985Hatanaka et al ( , 1988, Hori et al (2002) and Nagase et al (1999) employed undisturbed frozen samples, whereas Seki et al (1992) conducted block sampling, to compare the liquefaction resistance of aged soil with laboratoryreconstituted (young) specimens. Mulilis et al (1977) studied several sites to show the increase of liquefaction resistance over thousands of years.…”