IDENTIFIKASI DAN INTERPRETASI STRUKTUR BAWAH PERMUKAAN KAWASAN GUNUNG BROMO-SEMERU DENGAN METODE GRAVITASI

Aisyah Salsabila; Arie Realita; Muhammad Nurul Fahmi

doi:10.26740/ifi.v14n2.p171-177

Authors

Aisyah Salsabila Universitas Negeri Surabaya
Arie Realita Universitas Negeri Surabaya
Muhammad Nurul Fahmi Universitas Negeri Surabaya

DOI:

https://doi.org/10.26740/ifi.v14n2.p171-177

Keywords:

Mount Bromo-Semeru, Gravity method, TOPEX, Metode gravitasi, Gunung Bromo-Semeru

Abstract

Abstrak
Gunung Bromo-Semeru merupakan wilayah vulkanik aktif di Jawa Timur yang memiliki sumber daya vulkanik tinggi. Penelitian ini bertujuan untuk mengidentifikasi dan menginterpretasi struktur bawah permukaan kawasan tersebut berdasarkan data anomali gravitasi. Data sekunder anomali gravitasi diperoleh dari satelit TOPography EXperiment (TOPEX) dan dianalisis melalui beberapa tahapan koreksi, meliputi Free-Air Correction (FAC), koreksi Bouguer dan koreksi terrain. Peta Complete Bouguer Anomaly (CBA) yang dihasilkan kemudian dipisahkan menjadi anomali regional dan anomali lokal (residual) menggunakan metode Moving Avarage. Hasil interpretasi menunjukkan bahwa area sekitar kaldera Bromo didominasi oleh anomali negatif, yang mengindikasikan keberdaan batuan piroklastik lepas, zona rekahan dan potensi kantung magma dangkal. Sebaliknya, akibat intrusi magma berulang, wilayah selatan dan tenggara gunung semeru menunjukkan anomali positif yang diasosiasikan karena keberadaan batuan beku padat seperti andesit dan basalt. Temuan ini memberikan gambaran awal struktur geologi bawah permukaan dengan metode non-destruktif dan dapat mendukung eksplorasi sumber daya alam serta mitigasi bencana.

Abstract
Mount Bromo-Semeru is an active volcanic area in East Java that has high volcanic resources. This research aims to identify and interpret the subsurface structure of the area based on gravity anomaly data were obtained from TOPography EXperiment (TOPEX) satellite and analyzed trough several correction stages, including Free-Air Correction (FAC), Bouguer correction and terrain correction. The resulting Complete Bouguer Anomaly (CBA) map is then separated into regional anomalies and local (residual) anomalies using the Moving Avarage method. The result of interpretation show that the area around the Bromo caldera is dominated by negative anomalies, wich indicate the presence of loose pyroclastic rocks, fracture zones and potential shallow magma pockets. In contrast, due to repeated magma intrusion, the south and southeast areas of Mount Semeru show positive anomalies associated with the presence of solid igneous rocks such as andesite and basalt. These findings provide an initial picture of the geological structure below the surface with non-destructive methods and can support the exploration of natural resources and disaster mitigation.

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