Dynamic site characterization was performed at 25 sites located on the western portion of the Mexico City Basin that were severely damaged during the Mw7.1 2017 Puebla–Morelos, Mexico, earthquake. Testing was conducted using active and passive seismic surface wave methods and the microtremor horizontal-to-vertical spectral ratio method to determine site periods and develop one-dimensional (1D) shear wave velocity ( Vs) profiles for the first 60 m of the subsoil. The measured site periods were compared to site period maps developed in 2004 and 2020 along with values computed using the Design Seismic Actions System (SASID) software following the 2020 version of the Complementary Technical Norms for Seismic Design (NTC-DS). The most noticeable biases in the predictions from the 2004 site period map were observed between the boundary of Zone II and Zone IIIa, at which site periods are overestimated. These estimates were improved upon in the 2020 site period map and showed a close similarity with SASID computed site period values. The Vs, depth, and thickness of the lacustrine clay layer were also determined to be quite variable within the basin. The softest sites are located between the lakebeds with a Vs between 45 and 57 m/s. Sites located toward the outer rim of the North lakebed have a higher Vs between 80 and 100 m/s. The thickness of the clay layer varies significantly in the western side of the Basin with values ranging between approximately 3 and 34 m. Overall, the results of this study indicate good agreement with the model embedded in the SASID software. The results (1) emphasize the need to regularly monitor changes that occur over time in the lacustrine clay layer, (2) complement the development of models that improve our understanding of wave propagation within the Basin, and (3) update and improve Mexico City’s Norms.
A characterization of all idempotent uninorms satisfying the distributive property is given. The special cases of left-continuous and right-continuous idempotent uninorms are presented separately and it is also proved that all idempotent uninorms are autodistributive. Moreover, all distributive pairs of idempotent uninorms (pairs U\, U2 such that U\ is distributive over U2 and U2 is distributive over Ui) are also characterized.
The Almendares River is central to recreational and other activities in Havana, Cuba. However, monitoring indicated significant heavy metal contamination in river sediments, especially below Calle 100, the largest landfill in Havana. This work extended previous sediment studies by determining complementary Cu, Pb, Ni, Cr, Cd, and Zn levels in indigenous water hyacinths (Eichhornia crassipes; EC) above and below the landfill. Pb, Cu, and Zn were significantly elevated in EC roots below the landfill and also correlated with sediment data (p < 0.05), implying elevated levels likely result from landfill activity and might be useful biomonitors as river remediation proceeds.
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