Journal ID : TRKU-08-12-2020-11354
[This article belongs to Volume - 63, Issue - 01]
Total View : 349

Title : New Evidences from Magnetotelluric, Gravity, and Passive Seismic Tomography Data Interpretation of the Tecto-Volcano System Delineation in Southwestern Part of Central Java, Indonesia

Abstract :

Magneto telluric, Gravity, and Passive Seismic Tomography (PST) surveys were conducted over the southwestern part of Central Java, Indonesia. The thick volcanic sediments conceal the prospective sedimentary basin in the area, which has been researched for more than five decades without any significant results. New evidence of the tecto-volcano system in the study area was found based on the methods. The study reveals two major geological structures in the area. The northeast-southwest lineaments, which correspond to the Meratus Thrust-Folds were strike-slip faulted by the Pamanukan-Cilacap Fault Zone (PCFZ) in the northwest-southeast directions. The Meratus Thrust-Folds existence proved that the study area is related to the Paleogene Fore-Arc Basin. However, the Meratus Thrust-Folds has been vanished partially due to the volcanism activities. Superimposed calderas of the ancient-volcanoes system were distinct in the area. The circular patterns which are interpreted as the part of ring-fault are found based on the Gravity dataset as well as the geomorphology and geological formation. The old magmatic chamber and the volcano conduit system within the calderas have been modeled based on the Magneto telluric dataset and confirmed with the PST interpretations. The interpretation is constrained by the existing exploration well. Two eruption points delineated following the high-resistive zones of the Magneto telluric dataset, while another eruption points are estimated based on circular patterns. All of the eruption points are located at around PCFZ as the weak zone, where the plume passes through and rising the volcanoes.

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