Analysis of the Centrifuge Seismic Response of a Submarine Canyon with a Weak Layer

The offshore environment of southeastern Brazil is an important area for oil exploration. In this region, the formation of weak layers can occur due to variations in the rate of soil deposition. Although several studies have analyzed the seismic response of topographic features, centrifuge modeling including the presence of weak layers has been little explored. To address this gap, the present study employs centrifuge modeling to investigate the seismic response of three different ground profiles: one with a uniform clay deposit and two incorporating weak layers. Each profile begins with a flat ground configuration and subsequently, a canyon is excavated to assess the impact of topography on the seismic response of soft clay profiles. The centrifuge tests were conducted at an acceleration level of 40 g. The results showed that the weak layer intensifies the non-linearity of the soil and acts as a filter in the spectral response of the soil, limiting the propagation of higher frequency waves. While this leads to a reduction in amplification and spectral response energy, it also results in a noticeable extension of the earthquake’s significant duration at the model’s surface.