Electronic Theses and Dissertation

Metode magnetik merupakan salah satu metode geofisika yang memanfaatkan sifat kemagnetan bumi untuk mengetahui kondisi bawah permukaan. Penelitian ini menggunakan metode magnetik untuk melakukan pemetaan patahan di Pulau Weh. Pengambilan data dilakukan sebanyak 204 titik dengan jarak antar titik 500 meter di seluruh Pulau. Namun, di beberapa titik memiliki akses yang terbatas sehingga sulit dilakukan pengukuran seperti di kawasan hutan dan pegunungan dan area militer yang tidak dapat dimasuki. Pengambilan data dilakukan menggunakan alat Proton Precession Magnetometer (PPM). Pengolahan data dasar seperti koreksi diurnal dan koreksi International Geomagnetic Reference Field (IGRF) digunakan untuk memperoleh data intensitas magnetik total. Kemudian beberapa transformasi seperti reduksi ke kutub, analitik sinyal, Tilt Derivative dan Horizontal Derivative diterapkan untuk menghilangkan pengaruh inklinasi, deklinasi dan efek regional di lokasi pengukuran yang bertujuan untuk mendapatkan anomali patahan. Transformasi reduksi ke kutub tidak menunjukkan anomali yang dicari. Sedangkan hasil transformasi analitik sinyal, Tilt Derivative dan Horizontal Derivative didapatkan anomali sebanyak 13 patahan. Patahan-patahan tersebut berorientasi pada timur laut- tenggara Pulau Weh. Diperkirakan distribusi patahan tersebut merupakan kontinuitas dari Patahan Sumatera segmen Seulimum.
Kata Kunci: Patahan, Metode Magnetik, Reduksi Kutub, Analitik Sinyal, Tilt Derivative, Horizontal Derivative.

The magnetic method is a geophysical method that utilizes the earth's magnetic properties to determine subsurface conditions. This study uses a magnetic method to map the fault on Pulau Weh. Data were collected as many as 204 points with a distance between points of 500 meters across the island. However, some points have limited access, making it difficult to measure, such as in forest and mountainous areas and inaccessible military areas. Data were collected using a Proton Precession Magnetometer (PPM). Basic data processing such as diurnal correction and International Geomagnetic Reference Field (IGRF) correction is used to obtain total magnetic intensity data. Then several transformations such as reduction to the pole, signal analytic, Tilt Derivative and Horizontal Derivative are applied to eliminate the influence of inclination, declination and regional effects at the measurement location in order to obtain fault anomalies. The reduction to polar transformation does not show the anomali that is being sought. Meanwhile, the result of signal analytic transformation, Tilt Derivative and Horizontal Derivative obtained anomalies of 13 faults. The faults are oriented to the northeast-southeast of Pulau Weh. It is estimated that the distribution of the fault is a continuity of the Sumatra Fault in the Seulimum segment. Keywords: Fault, Magnetic Method, Pole Reduction, Signal analytics, Tilt Derivative, Horizontal Derivative.