TDEM survey in urban environmental for hydrogeological study at USP campus in Sao Paulo city, Brazil

Author(s)

Porsani, Jorge Luis ^[1] ; Bortolozo, Cassiano Antonio ^[1] ; Almeida, Emerson Rodrigo ^[1] ; Santos Sobrinho, Esther Novais ^[1] ; dos Santos, Thiago Gomes ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atomosfer IAG, Dept Geofis, BR-05508090 Sao Paulo - Brazil

^[2] IAG USP, Geosoft - Brazil

• Document type: Journal article
• Source: JOURNAL OF APPLIED GEOPHYSICS; v. 76, p. 102-108, JAN 2012.
• Web of Science Citations: 13

Abstract

In this work, some TDEM (Time Domain Electromagnetic) results at USP (University of Sao Paulo) campus in Sao Paulo city, Brazil, are presented. The data were acquired focusing on two mains objectives: (i) to map geoelectrical stratigraphy of Sao Paulo sedimentary basin, emphasizing on hydrogeological studies about sedimentary and crystalline aquifers, and (ii) to analyze the viability of TDEM data acquisition use in urban environment. The study area is located in Sao Paulo basin border, characterized by Resende and Sao Paulo formations, which are constituted by sand-clays sediments over a granite-gneissic basement. Two equipments were used in order to acquire database: Protem47 (low power), and Protem57-MK2 (high power). Capacitive noise affect obtained data with Protem47 due to the presence of metal pipes buried at IAG/USP (Institute of Astronomy, Geophysics, and Atmospheric Science) test site at USP. On the other hand, capacitive noise did not affect acquired data with Protem57-MK2, and the data present high signal to noise ratio. Surveys helped in determining sedimentary and crystalline aquifers, characterized by a fracture zone with water inside basin basement (conductive zone). Results show good agreement with local geology obtained from lithological boreholes located in the study areas. Moreover, it shows that TDEM method can be used in urban environments with a countless potential in hydrogeological studies, offering great reliability. Studies showed that main TDEM-method limitation at USP was the lack of space for opening the transmitter loop. Results are very promising and open new perspectives for TDEM-method use in urban environments as this area remains unexplored. (C) 2011 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 09/08466-3 - Geoelectric characterization of fractured aquifers in basalt in the region of Bebedouro, SP, by using joint inversion of SEVs and TDEM soundings
• Grantee: Jorge Luís Porsani
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/19769-7 - TDEM survey in urban environmental for hydrogeological study at USP campus in São Paulo city, Brazil.
• Grantee: Jorge Luís Porsani
• Support Opportunities: Regular Research Grants - Publications - Scientific article