Metoda Pseudo-Gravity Dalam Analisis Kelurusan Dan Patahan Di Sekitar Tinggian Asahan, Perairan Selat Malaka.

Abstract

Melalui teori medan dalam metoda magnetik dan gaya berat, ambiguitas yang muncul merupakan suatu faktor yang menyulitkan dalam penerapan kedua metoda ini. Terlebih pada penerapan metoda magnetik yang memiliki efek polaritas positif dan negatif. Beberapa teknik dan metoda telah diterapkan dalam melakukan analisis dan pengolahan data anomali magnet untuk mengatasi masalah ambigutas ini dengan tujuan mempermudah dalam melakukan interpretasi. Salah satu metodanya yaitu transformasi data anomali magnet ke dalam data pseudo-gravity. Metoda ini akan diterapkan dalam analisis dan pengolahan data anomali magnet di sekitar Tinggian Asahan dalam hal ini untuk menganalisis kelurusan dan patahan yang muncul di area ini. Hasil transformasi akan dibandingkan dengan data skunder berupa ketebalan sedimen dan patahan di area yang sama. Hasil penerapan metoda ini memperlihatkan adanya indikasi kelurusan ataupun patahan muncul, yang tidak terlihat jelas pada data aslinya yaitu anomali magnet.
 
 Kata Kunci : Transformasi, Pseudo-Gravity, Tinggian Asahan.
 
 
 Through potential field theory in magnetic and gravity methods, ambiguity that presented is the difficult factor in the application of both methods. Moreover the application of magnetic method which involve the effect of positive and negative polarity are more complicated. Some techniques and methods have been used to overcome problem of ambiguity in order to make easier interpretation. One of the techniques is the transformation from anomaly magnetic to pseudo-gravity data. This method will be used within analysis and processing anomaly magnetic data at Asahan Arch to analyze lineaments and faults that appear in this area. Transformation result will be compared with another data which is secondary data about sediment thickness and fault at the same area. This technique shows that indication of fault more clearly than the original data or anomaly magnetic data.
 
 Key Words: Transformation, Pseudo-Gravity, Asahan High.

Identification of Rock Layer Contacts in the Surrounding of the Sutami Dam Using Geomagnetic Methods

“…Pseudogravity is used to change the previously dipole's geomagnetic anomaly to monopole as if it were a gravity anomaly [15]. The pseudogravity transformation can strengthen the subsurface structure analysis by calculating the magnetization value ratio to the pseudo-density value.…”

Two Dimensional Modeling of Basaltic Rocks Intrusion Based on The Local Magnetic Anomalies Data in Jatilawang District Banyumas Regency

“…This complicates the interpretation process, especially quantitative interpretation which aims to model the subsurface anomalous sources, such as basalt rocks intrusion. To clarify the location of subsurface anomalous sources, then a pseudogravity transformation was applied [15] . Transformation is conducted by changing the magnetic anomalies data into pseudogravity anomalies data as explained in Method.…”

“…Transformation is conducted by changing the magnetic anomalies data into pseudogravity anomalies data as explained in Method. Pseudogravity transformation is a technique to interpret magnetic anomalies data qualitatively [15] . The pseudogravity anomalies data obtained from this calculation have values ranging of -115.94 -124.29 mGal, with contour map as shown in Figure 6.…”

“…To localize the subsurface anomalous source that was the target of the research, the local magnetic anomalies data were transformed into pseudogravity anomalies data, using the formulation which has been explained in Equation ( 1). The pseudogravity anomalous map associated with density can be used to localize basaltic rock in the research area [15] . The pseudogravity anomalous map is used as a reference for 2D-forward modeling to the local magnetic anomalies data.…”

Inovasi pemanfaatan peta anomali pseudogravitasi untuk interpretasi pola sebaran batuan andesit masif di desa Candiwulan kecamatan Kutasari kabupaten Purbalingga dan sekitarnya

“…Tidak semua singkapan dapat didokumentasikan akibat terkendala faktor alam. Perbedaan kecil antara foto singkapan batuan dengan peta anomali pseudogravitasi bisa dipahami, mengingat peta anomali tersebut lebih merepresentasikan distribusi sumber anomali atau batuan yang berada di bawah permukaan [19]. Hasil overlay antara peta kontur anomali pseudogravitasi dengan peta geografis daerah penelitian dapat dilihat pada Gambar 10.…”