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Schlagwörter:
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Zusammenfassung:
Among the key aspects for the analysis of artificial water Reservoir-Triggered Seismicity (RTS) is the adequate setting of the 4D spatiotemporal distribution of water loads, usually based on the Digital Elevation Models (DEMs) of the reservoir basin, and the observed temporal evolution of the water levels. Somehow, in some cases, the access to a detailed lake bathymetry for old reservoirs is generally limited.
Here we study the 4D spatiotemporal evolution of the stress changes as a function of the 3D configuration of the bathymetry, and the temporal changes in the water level in dams, using real and theoretical 3D DEMs. First, surface loads are modeled using 3D theoretical configurations for the bathymetry and water levels time evolution, considering the actual aspect ratio of the lakes. Stress changes (ΔCFS), are computed for an elastic halfspace, calculated using the full 3D stress tensor. Then, stress changes from theoretical models are compared with those produced by the real DEMs of the dam. The analysis is carried out for three different reservoirs: the Aguamilpa reservoir in Mexico, with a storage capacity SC=5480 hm3, the Itoiz reservoir in Spain, with a SC=418 hm3 and the Pirrís reservoir in Costa Rica with a SC=30 hm3. Stresses are compared with the corresponding seismic series occurred after the initial filling of the three dams. Results show that theoretical models adequately reproduce the main effects of surface loads even at relatively shallow depths, showing their suitability for the analysis on the possible induced shallow seismicity.
