Ahmad Muhadjir Utama

Program Studi Geofisika, Universitas Tanjungpura, Jalan Prof. Dr. Hadari Nawawi, Pontianak, Kalimantan Barat, 78124, Indonesia

Muhardi

Program Studi Geofisika, Universitas Tanjungpura, Jalan Prof. Dr. Hadari Nawawi, Pontianak, Kalimantan Barat, 78124, Indonesia

Radhitya Perdhana

Program Studi Geofisika, Universitas Tanjungpura, Jalan Prof. Dr. Hadari Nawawi, Pontianak, Kalimantan Barat, 78124, Indonesia

DOI: https://doi.org/10.19184/bst.v14i2.60007

ABSTRACT 

This study aims to model the subsurface structure in Kutai Kartanegara Regency based on Free Air Anomaly (FAA) gravity data from the TOPEX satellite. Bouguer and terrain corrections were applied to obtain the Complete Bouguer Anomaly. Regional and residual anomalies were separated using the upward continuation method. Modeling was performed on the regional anomalies to identify the subsurface structure at the study location. The modeling results show that there are six rock formations: the Kampung Baru Formation (Tpkb) has a density of 2.31-2.35 g/cm3, the Balikpapan Formation (Tmbp) has a density of 2.44-2.5 g/cm3, the Pulau Balang Formation (Tmpb) has a density of 2.538 g/cm3, the Bebuluh Formation (Tmb) has a density of 2.21 g/cm3, the Pamaluan Formation (Tomp) has a density of 2.36-2.39 g/cm3, and the Alluvial Deposit (Qa) has a density of 2.2 g/cm3. The 2D modeling also shows subsurface geological structures in the form of anticlines, synclines, and thrust faults.

Keywords: Bouguer; Free air anomaly; Gravity; Subsuface structure.