Iranian Journal of Geophysics

Iranian Journal of Geophysics

Subsurface lithological interpretation of the landslide-prone Cipendawa area, Cianjur (Indonesia), using 2D and 3D inversion of aeromagnetic data

Articles in Press

Document Type : Research Article

Authors
Ahmad Ali Muckharom 1
Agus Setyawan 2
Agustya Adi Martha 3
Bono Pranoto 4
Tio Azhar Prakoso Setiadi 5
1 M.Sc., Physics Department, Faculty of Science and Mathematics, Diponegoro University, Semarang, Indonesia
2 Professor, Physics Department, Faculty of Science and Mathematics, Diponegoro University, Semarang, Indonesia
3 Ph.D., National Research and Innovation Agency (BRIN RI), West Java, Indonesia
4 M.Sc., National Research and Innovation Agency (BRIN RI), West Java, Indonesia
5 Ph.D., Student, National Research and Innovation Agency (BRIN RI), West Java, Indonesia
10.30499/ijg.2025.493770.1654
Abstract
Cipendawa, Cianjur (Indonesia), has been declared unsuitable as a permanent housing relocation site for earthquake victims due to the slope of the land, soft soil conditions, and the potential for volcanic eruptions. This research aims to interpret the subsurface structures of the Cipendawa area using the aeromagnetic method, considering variations caused by heterogeneous subsurface lithology. Data acquisition was carried out using a drone-mounted Sensys R3 magnetometer at 135 measurement points, including measurements of total magnetic field. Data processing included IGRF (International Geomagnetic Reference Field) correction, reduction to the pole (RTP), and both two-dimensional and three-dimensional modeling. Qualitative interpretation results indicate three magnetic anomaly patterns. High magnetic anomalies (245 nT-441 nT), observed in the southeastern and northwestern parts of the area, are interpreted as volcanic rocks such as basalt and andesite. Medium magnetic anomalies (193 nT-238 nT), located in the southwestern and central areas, are thought to be sandstone. Low magnetic anomalies (-21 nT-185 nT), found in the northern parts, are interpreted as limestone and sandstone. The analysis of three cross-sections shows variations in rock susceptibility from -23×10-4SI to 54×10-4SI within the depth range of 0-40 meters. It indicates that the northern area consists of sedimentary rocks, such as sandstone, formed by river flow that carries magnetite-rich minerals, while the southern area is composed of volcanic rocks, such as andesite breccia, which align with the geological map due to magma intrusion from Mount Gede in the past. Furthermore, three-dimensional modeling of the Cipendawa area indicates that the landslide-prone sedimentary rock layer is located in the northern part, while the hard rock layer in the southeastern part is more stable. However, the southeastern region could still experience landslides in the event of tectonic activity.
Keywords
IGRF, landslides, lithology, subsurface, magnetic method, RTP

Subjects

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Iranian Journal of Geophysics

Articles in Press, Accepted Manuscript
Available Online from 28 April 2025