Comparison Among Subsurface Linear Features of Residual Gravity Fields at the Eastern and Western Parts of Central Iraq by Applying the THD Filtering Technique.

Abstract

In this study, upward continuation technique is considered as a clean filter because it produces no side effect like other filters which are used in used in processing in order to acquire residual gravity data in the western and eastern regions of the central part of Iraq. The residual anomaly maps achieved to 2km, 12km, 16km, and 22km upward elevation levels. The approximate equivalent depth of detection for the four upward continuation elevation levels generally ranges (1.6, 10, 13 and 18 km respectively) in relation to the upward continuation elevation. The Total Horizontal Derivative (THD) technique applied to the residual anomaly maps In order to identify the subsurface linear features (faults or source boundaries) for the two studied parts. The THD measures the lateral rate of change of the measured gravity field. It is useful to detect the edges and delineate the boundaries (Faults), where the peak values occur over the edge of block. The most lineament trends in western part area are in the NW-SE direction, and ,while lesser trends were in the direction NE-SW. The N55W, N45W, and N35W trends percentage is 51% of all lineaments in the western part. The percentage of the three mention trends for the four considered levels range 48-60%, where the percentage value increase with the deeper lineaments, this may indicate the faults in the sedimentary cover affected by the basement rocks.