Analysis of Seismic Amplification of Soil to the Preservation of the Archaeological Park of Saqsaywaman – Cusco Peru

The Archaeological Park of Saqsaywaman was officially declared Cultural Heritage of Peru on 11th July 1982 for its historical, archaeological and natural value and for being an inherent part of the ancestral Andean conception and of the current image of the city of Cusco-Perú. In 2009 the walls of the third terrace of Sacsaywaman were damaged. It is assumed that these events were caused by the lateral thrust created by the additional hydrostatic pressure due to rainfall runoff and seismic movements. The problem now, is to preserve the restored walls for posterity. The research assess the dynamic response by means two-dimensional analysis. This analysis determine the seismic behavior of the site in terms of the seismic amplification of the surface ground. This is resulting of effects of topography and stratigraphy. For this purpose, two cross sections of the stratigraphic profile were selected. Non-destructive techniques were used to conduct geophysical surveys applying Multichannel Surface of Wave Analysis (MASW), Seismic Refraction, Microtremor Array Measurement (MAM) methods as well as the Nakamura technique for fundamental period studies. Georadar (GPR) surveys were also performed. Results show that the amplifications within the range of 1.37 to 2.35. The maximum acceleration obtained from the ground varies between 0.30 g and 0.52 g. Also, spectral ratio of the surface register and the rock record was determined to obtain the soil vibration period from 0.45 s to 0.55 s, which was then compared with vibration period obtained from microtremor measurements.