LIQUEFACTION AND THE 1992 ROERMOND EARTHQUAKE, THE NETHERLANDS

The scanty information available on liquefaction phenomena during the Roermond earthquake does not allow firm conclusions on the technical s ignificance of these phenomena. However, speculations based on applied mechanics principles justify a few conclusions on what happened and w hat did not happen. First, the presence of fracture vents and sand boi ls agrees well with the estimated earthquake magnitude M(L) = 5.8-5.9; second, the rare occurrence of sand boils and the absence of visible settlements indicate that liquefaction was not an important phenomenon during the earthquake; third, damage of farms due to liquefaction see ms absent. This observation is in agreement with the theoretical analy sis of responses of the farm foundations to liquefaction. If the area affected by liquefaction had exceeded some 1% of the total area, signi ficant damage would have been detectable. The low ground water tables during the time of the earthquake have most probably prevented extensi ve damage.