Contributions of TDEM Survey in a Seismic Activity Area Triggered by Wells in Paraná Basin, Brazil - Preliminary Results

Abstract

This article present TDEM results on a seismic activity area triggered by groundwater exploitation from deep wells. The study area is situated at Paraná basin, São Paulo state, Brazil. Stations were individually arranged next to wells and along profiles. Preliminary result showed the geoelectrical stratigraphy of Paraná basin. 1st geoelectrical layer is constituted by sedimentary aquifer, followed by top of basalt layer that occur ~60-80 m depth. A fractured zone filled with water within of the basaltic layer was found between 100-300 m depth, which agree to the depth estimated for more than 3000 micro earthtremor hypocenter in the studied region. The bottom of the basalt layer was estimated between ~400-650 m depth. The last geoelectrical layer is characterized by Botucatu sandstone. Results suggest that the high water flow in some wells seems to be related to the presence of fractured zones filled with water founded in the middle of basalt layer. Moreover, there are a good correlation between the seismic activities area and the fractured zones filled with water, which some wells presented the high flux of groundwater. This is a good result which suggest that the shallow seismic activity, can probably is being triggered by water wells drilling.