Application of MASW and SRT Surveys in Engineering Geotechnical Evaluation for Safe Urban Extension: A Case Study in Eastern Agadir, Morocco

Despite the strategic and economic importance of the Agadir area, many buildings in the city were constructed without a thorough understanding of the subsoil. The 1960 Agadir earthquake, even though it had a moderate magnitude (Mw = 5.8), led to the destruction of more than 75% of the city, revealing the vulnerability of its structures. Due to population growth, the Eastern Agadir area was chosen as a planned urban expansion area. To ensure the durability of structures and safe urban development, extensive geotechnical investigations are needed. However, these investigations are expensive and time-consuming. Our main goal is to determine the geotechnical, petrophysical, and elastic-dynamic properties of the subsoil using seismic surveys, which are cost-effective and efficient. We used MASW and SRT to calculate S-waves and P-waves, respectively and then derived the mentioned properties. Our results show three layers: (1) The first layer, with a thickness of 5 m, has VP and VS values ranging from 382 to 3757 m/s and 220 to > 850 m/s. (2) The second layer, at a depth of -5 to -10 m, has VP and VS values ranging from 432 to 3494 m/s and 215 to > 850 m/s. (3) The third layer, located at -10 to -20 m, has VP and VS values ranging from 432 to 432 m/s and 215 to > 850 m/s, respectively. VS30 was calculated for near-surface geologic materials by applying the EUROCODE 8 classification. The study area was categorized into three classes: class A, class B, and class C. We have provided maps and tables containing the calculated parameters.