Fault rupture-foundation interaction: Selected case histories

The 1999 earthquakes in Turkey and Taiwan, offering a variety of case histories with structures subjected to large tectonic displacements, have refueled the interest of the earthquake engineering community on the subject. While several structures were severely damaged or even collapsed, there were numerous examples of satisfactory performance. Even more astonishingly, in specific cases the surface fault rupture was effectively diverted due to the presence of a structure. For the purpose of developing deeper insights into the main mechanisms controlling this fascinating interplay, this article documents selected field case histories of fault rupture-foundation interaction from (a) the M 7.4 Kocaeli (August 17) 1999 earthquake in Turkey, (b) the M 7.1 Düzce-Bolu (November 12) 1999 earthquake in Turkey, (c) the M 7.6 Chi-Chi (September 21) 1999 earthquake in Taiwan, and (d) surface faulting in Mount Etna. A subset of the case histories presented herein is analysed numerically, using the methods developed in the companion paper. It is shown that relatively "heavy" or stiff structures supported by continuous and rigid foundations may divert the fault rupture. Such structures are subjected to rigid body rotation, without substantial structural distress. In contrast, structures on structurally-resilient foundation systems or on isolated supports are prone to substantial damage.