Liquefaction beyond the Near Field

Groundwater level changes induced by the 2011 Tohoku earthquake in China mainland

“…Thirdly, the 'enhanced permeability' model was promoted as the most plausible mechanism for sustained water level changes in recent studies (Rojstaczer & Wolf 1992;Rojstaczer et al 1995;Roeloffs 1998;Brodsky et al 2003;Elkhoury et al 2006;Wang Within each box, the central mark is the median, the edges of the box are the 25th and 75th percentiles, the whiskers extend to the most extreme outlying data points, and outliers, which are plotted individually with crosses. (b) Boxplot of the M 2 tidal factors grouped into three categories with respect to the water level response to the Earth-circling surface waves: no 2nd Earthcircling wave, clear response, that is several Earth-circling waves, and no obvious response.…”

“…(Holzer et al 2005;Wang 2007), control the distribution of aftershocks (Nur & Booker 1972;Bosl & Nur 2002), trigger earthquakes and volcanic eruptions (Hill et al 1993;Prejean et al 2004) and may provide evidence of possible hydrogeological earthquake precursor mechanisms (Igarashi et al 1992;Roeloffs 1998;Matsumoto & Roeloffs 2003). In general, there are two types of co-and post-seismic responses recorded in groundwater levels: transient dynamic oscillations (Blanchard & Byerly 1935;Cooper et al 1965;Liu et al 1989;Kitagawa et al 2011) and sustained changes.…”

Hydrological effects of theMW7.1 Darfield (Canterbury) earthquake, 4 September 2010, New Zealand

“…Earthquake engineers commonly think of liquefaction in terms of Terzaghi's concept, whereby consolidation and densification of loose sediments temporarily increases the pore pressure and results in liquefaction (Seed & Lee 1966;National Research Council 1985;Terzaghi et al 1996). While Terzaghi's mechanism may be valid in the near-field of an earthquake, it has been noticed that the energy of seismic waves may be too small to induce consolidation and explain occurrences of liquefaction at intermediate-and far-field distances (Wang 2007). This has led to the idea that redistribution of pore pressure by earthquake-enhanced permeability could be an important mechanism that is not accounted for, or replicated, in laboratory experiments (Wang 2007;Wang & Manga 2010a).…”

Frequency dependence of mud volcano response to earthquakes

“…There is a clear pattern in that larger earthquakes can trigger eruptions at greater distances. Also shown in Figure 1 is an estimate of the energy dissipated by the seismic waves at the eruption location [Wang, 2007]. Eruptions appear to be triggered for energy densities as small as 10 À1 J/m 3 .…”

“…Eruptions appear to be triggered for energy densities as small as 10 À1 J/m 3 . To put this number in perspective, sediments prone to liquefaction require energy densities >30 J/m 3 [Green and Mitchell, 2004] to liquefy by undrained consolidation, the mechanism thought to be responsible for liquefaction in the near-field [Wang, 2007]. Thus, the eruption of previously existing mud volcanoes is not likely to arise from the processes that create the small mud and sediment eruptions produced by liquefaction of shallow sediments.…”