Reply to discussion on ‘Spectral analysis of aeromagnetic data for geothermal energy investigation of Ikogosi Warm Spring - Ekiti State, southwestern Nigeria’

Abstract

In reply to Geothermal Energy 2:11 comments about possible errors in our recent paper Geothermal Energy 2:6, 1-21 with title 'Spectral analysis of aeromagnetic data for geothermal energy investigation of Ikogosi Warm Spring -Ekiti State, southwestern Nigeria', we show that there are no errors in the published paper. Our choice of 55 × 55 km block dimension slide across the magnetic anomaly map is consistent with the derived Curie point depths. This choice was adopted because of complexity of the geology in the area and the need to sample more data points while preserving the spectral peak. All depth estimates were carefully and thoroughly performed and assessed using tectonic framework, geological and geophysical evidence, heat flow, seismicity, and other independent information.

Precambrian tectonic inheritance control of the NE Brazilian continental margin revealed by Curie point depth estimation

“…An important debate about the CPD estimation involves the definition of the effective width of the sampling window, which is an essential part of the centroid method [Bouligand et al, 2009;Li et al, 2010;Abraham et al, 2014aAbraham et al, , 2014bNwankwo and Shehu, 2015]. Some authors argue that large square windows are necessary to ensure that the response of the deepest magnetic layers is captured and that the use of windows with small widths cannot efficiently resolve deep sources.…”

Energy Status, Energy Mix and Renewable Energy Potentials of Nigeria

“…Farming, industrial and domestic hot water use, and individual and residential district heating are examples of direct thermal uses of geothermal energy. Heat pumps are also widely used in temperate climates (Abraham et al, 2014).…”

Investigating heat and magnetic source depths in the Soutpansberg Basin, South Africa: exploring the Soutpansberg Basin Geothermal Field

“…The largest window size with L of 129 km and six data points ensured that spectral signatures were preserved. The authors, therefore, utilised three window sizes to verify discussions on the choice of window sizes that supported the use various and larger window sizes for the spectral analyses of data for depth determinations (Nwankwo 2014;Abraham et al 2014). The radially averaged power spectrum (RAPS) was generated from the transformed airborne magnetic data.…”

“…(Shabalala et al 2015) In the computation of spectral energies, the data windows should have dimensions, L that ensure that the computed depths are within and more that the value of, L/2π to improve the depth resolution from spectral analysis (Nwankwo 2014). Abraham et al (2014), however, argued that dimensions of L ranging from 40,41,130,150, and 222 km have been applied to determine depths of 10, 15, 30, 32, and 46 km, respectively, on several case studies. Nwankwo et al (2009) previously obtained a depth of 30 km from the analysis of a data set with an L of 45 km.…”