Unraveling the Enigma of the 2022 Cianjur Earthquake: Insights from Gravity Satellite Data

The 2022 Cianjur Earthquake serves as a stark reminder of the omnipresence of active faults. Despite its moderate magnitude of M5.6 and its distance from the well-known Cimandiri Fault, this earthquake resulted in over 600 fatalities and substantial damage. It presented an unusual challenge, lacking the strength to induce surface rupture or deformation yet causing remarkably intense shaking and scattered building damage. This study employs gravity satellite data, specifically TOPEX data, to explore subsurface anomalies tied to geological structures within the earthquake-affected region. Through mapping, we identify gravity anomalies associated with geological features, active faults, and volcanoes. Our analysis incorporates aftershock distribution, overlaid with a Forest and Building Removed Digital Elevation Model, and geological mapping. Our findings reveal the earthquake's hypocenter positioned amidst gravity anomalies of varying magnitudes. Additionally, we observe that aftershocks are concentrated between two hills of an ancient quaternary volcano, forming a fan-like pattern. Historical earthquake and volcano eruption databases are consulted to assess the potential triggering of volcano flank collapses by past earthquakes. Notably, we detect minor structures suggestive of surface rupture near the landslide-prone area, offering a pivotal location for future investigations into subsurface active faults. For advanced studies, we recommend detailed gravity measurements to enhance structural analysis and understand the subterranean configuration near the earthquake epicenter. Additionally, methods such as electrical resistivity tomography and ground-penetrating radar should be considered. In conclusion, our research underscores the value of an integrated approach, encompassing geophysics, geology, and remote sensing, for comprehensive earthquake studies in this region.