STUDY OF DEEP AQUIFERS IN THE LAVA FAN OF THE HARUMAN AREA, WESTERN MALABAR MOUNTAINS, BASED ON 1D AUDIO MAGNETOTELLURIC DATA

Abstract

Haruman is one of the peaks in the Malabar Mountains, located in the southern region of the Bandung Basin. The Malabar Mountains play a critical role as a recharge area that feeds the Bandung-Soreang Groundwater Basin. This role is supported by the region's dense vegetation, high rainfall, and slopes that drain directly into the southern part of the Bandung Basin. Shallow aquifers in the Puncak Haruman area have been identified at depths of less than 40 meters. This study aimed to investigate the presence of deep aquifers in the Haruman Peak area using the Audio Magnetotelluric (AMT) method. AMT data acquisition was conducted at three measurement points located north of the suspected fault. The inversion process produced a 1D model representing subsurface resistivity values, which was used to identify lithology and aquifer layers. The subsurface layers beneath the Haruman Peak area were interpreted to consist of soil, Malabar-Tilu Volcanics (Qmt), and Waringin-Bedil Andesite, as well as the Old Malabar (Qwb) formations. Deep aquifers were found at depths of 1322 meters and 804 meters at points MB-01 and MB-02, respectively. Meanwhile, at point MB-03, a shallow aquifer was found at a depth of less than 100 meters within the soil layer.