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Abstract

Reservoir-Triggered Seismicity is an unnatural phenomenon, recorded concomitantly and/or after the filling of a hydroelectric plant reservoir, where previously there was no record of seismic activity. The local geology is commonly the main parameter for seismic risk analysis, although recent studies suggest that the environmental noise also plays an important role. Thus, a study of the local response analysis was carried out in the hydroelectric reservoir in Nova Ponte, in the state of Minas Gerais. This reservoir was selected because it is classified as a case of seismicity triggered by the reservoir. Data was collected with short-period and broadband seismometers in 74 stations with spacing up to 2 km. These measures were used for the calculation of the Fundamental Frequence (f0) using the Nakamura technique, from which the depth of layers could be constrained. Layer-depth values could be compared with previous seismicity and microzonation maps, as well as with geological structures. From the correlation of shallow crustal structures (such as faults) with layer-depths, it is possible that these structures can be forced by the change of direction and intensity in the field of local tensions, generating the seismicity events triggered by the reservoir.