Compact inversion of induced polarization spectrum

• Grant number: 13/22165-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2014
• End date: June 30, 2015
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal Investigator: Carlos Alberto Mendonça
• Grantee: Andréa Teixeira Ustra
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The Spectral Induced Polarization method (SIP) has been considered a promising methodology for hydrogeophysics and environmental studies. Nordsiek and Weller (2008) developed a new approach to fit SIP data, called Debye Decomposition (DD), where magnitude and phase spectra are considered a superposition of distinct Debye spectra, characterized by a specific chargeability (obtained by minimum Euclidean norm criterion) and relaxation time. This procedure presents great flexibility fitting the data, but cannot isolate specific chargeability values to identify specific relaxation times, as predicted by induced polarization models for sediments and rocks. The minimum Euclidean norm condition cannot retrieve individual relaxation times values and, because it establishes a gradual variation amongst the true values, produces a fictional values range, with no clear association with the polarization process. This limitation has been partially overcome assuming a total chargeability and a dominant relaxation time, which restricts the method potentialities, especially if there is more than one characteristic relaxation time. The objective of this project is to apply the DD using the compact distribution constrain (or compact inversion). Potentially, the compacity constrain may allow specific chargeabilities and its associated relaxation times to be identified in the inversion. The inversion algorithm will be tested on a wide SIP data based which was published in several studies that investigated the relation between SIP parameters and organic contaminant concentration, abiotic and biotic mineral precipitation and biodegradation effects on sediments.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

USTRA, ANDREA; MENDONCA, CARLOS ALBERTO; NTARLAGIANNIS, DIMITRIOS; SLATER, LEE D.. Relaxation time distribution obtained from a Debye decomposition of spectral induced polarization data. GEOPHYSICS, v. 81, n. 2, p. E129-E138, MAR-APR 2016. (13/22165-1)