scholarly journals Pemodelan 2D Batuan Bawah Permukaan Daerah Mamuju Sulawesi Barat Dengan Menggunakan Metode Magnetik

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Muhammad Irsyad ◽  
Sutrisno Sutrisno ◽  
Dwi Haryanto
Keyword(s):  
Magnetic Anomaly ◽  
Magnetic Anomalies ◽  
Magnetic Method ◽  
Government Agencies ◽  
Quantitative Interpretation ◽  
Magnetic Intensity ◽  
Contour Map ◽  
A Value ◽  
Qualitative Interpretation ◽  
The Earth

Abstrak. Batuan merupakan benda yang berasal dari magma yang mendingin di dalam bumi. Untuk mengetahui kondisi batuan perlu di lakukan penelitian. Mamuju merupakan daerah yang sedang hangat dalam perbincangan peneliti tentang bagaimana kandungan di bawah permukaan daerah Mamuju, Sulawesi Barat. Daerah ini juga merupakan daerah yang diteliti oleh instansi-instansi pemerintah termasuk PTBGN-BATAN. Penelitian ini bertujuan untuk melakukan pemodelan bawah permukaan bumi. Tujuannya untuk memberikan informasi tentang kondisi baik itu bentuk maupun kedalaman batuan. penelitian ini menggunakan metode magnetik dan metode ini merupakan metode yang tepat untuk membuat model bawah permukaan bumi. Hasil interpretasi kualitatif diperoleh peta kontur intensitas magnetik total dan anomali magnetik. Peta kontur intensitas magnetik total memiliki nilai sebesar 41286,5 – 42280 nT. Sedangkan anomali magnetik memiliki nilai -760,1 – 231,8 nT. Daerah A dan daerah B merupakan daerah yang memiliki anomali tinggi. Hasil interpretasi kuantitatif didapat ada 4 model bawah permukaan yang masing-masing terdapat batuan yang sama yaitu batuan breksi dengan nilai suseptibilitas 0,0006 – 0,00075 satuan cgs dan batuan lava dengan nilai suseptibilitas 0.001 – 0.0015 satuan cgs. daerah yang dilakukan pemodelan fokus pada daerah Hulu Mamuju, hal ini disebabkan karena menurut peta kontur daerah tersebut merupakan daerah yang memiliki anomali magnetik yang tinggi.   Abstract. The rocks are objects derived from the magma cooled in the earth. To determine the condition of the rock is necessary to do research. Mamuju is an area that is warm in conversation investigators about how the content of subsurface area Mamuju, West Sulawesi. This area is also the area investigated by government agencies including PTBGN-BATAN. This study aimed to modeling subsurface. The goal is to provide information about the condition of both the shape and depth of rock. This study uses a magnetic method and this method is an appropriate method to create a model of the earth's subsurface. Qualitative interpretation of results obtained contour map of total magnetic intensity and magnetic anomalies. The total magnetic intensity contour map has a value of 41286.5 to 42280 nT. While the magnetic anomaly has a value of -760.1 - 231.8 nT. Area A and area B is an area that has a high anomaly. Results obtained quantitative interpretation there are 4 models of the subsurface that each contained the same rock is rock breccia with values susceptibility of 0.0006 to 0.00075 cgs units and lava rock with susceptibility value 0.001 - 0.0015 cgs unit. modeling area focuses on upstream area Mamuju, this is because according to the contour map of the area is an area that has a high magnetic anomaly.

scholarly journals A Geophysical Survey with Magnetic Method for Interpretation of Iron Ore Deposits in the Eastern Nusawungu Coastal, Cilacap Regency, Central Java, Indonesia

2020 ◽  
Vol 5 (1) ◽  
pp. 47-55
Author(s):  
Muhammad Sehah ◽  
Sukmaji Anom Raharjo ◽  
Azmi Risyad
Keyword(s):  
Magnetic Anomaly ◽  
Iron Ore ◽  
Magnetic Anomalies ◽  
Research Area ◽  
Ore Deposits ◽  
Magnetic Method ◽  
Contour Map ◽  
Strength Data ◽  
Central Java ◽  
Iron Ore Deposits

Geophysical survey with magnetic method to interpret the iron ore deposits in the Eastern Nusawungu Coastal, Cilacap Regency, Central Java, Indonesia was carried out during six month, i.e. March –August 2017, covering the area in the geographical position of 109.3462° – 109.3718° E and 7.6958° – 7.7098° S. This survey has produced total magnetic field strength data at each measuring point in the research area. The magnetic field strength data which have been obtained, then be processed, corrected, and mapped so that the local magnetic anomaly contour map can be obtained. The local magnetic anomaly contour map shows the distribution of magnetic anomalous sources in the subsurface of research area. The 2D-modeling of magnetic anomalies data has been carried out along the AB trajectory extending on the local magnetic anomaly contour map from the position of A(109.3463°E and 7.7023°S) to B (109.3688°E and 7.7053°S), so that some subsurface anomalous objects is obtained. The modelling results of magnetic anomalies data show that the research area is estimated to have the potential of iron ore deposits. The subsurface rocks deposits containing iron ore are estimated to be located below the AB trajectory with a length about of 164.85 meters, a depth ranging of 1.709 – 31.909 meters, and a magnetic susceptibility value of 0.0122 cgs unit. These rocks are interpreted as sand deposits which coexists with silt and clay containing iron ore grains from the alluvium formation. Further, iron ore is also estimated to be present in the rocks deposits below the AB trajectory which have a depth of 24.405 – 49.809 meters and 3.989 – 11.111 meters, with the magnetic susceptibility values of 0.0093 and 0.0073 cgs units.

scholarly journals Interpretasi Bawah Permukaan Daerah Penambangan Batuan Andesit Awang Bangkal Kabupaten Banjar Kalimantan Selatan Menggunakan Metode Magnetik

2019 ◽  
Vol 16 (2) ◽  
pp. 117
Author(s):  
Ayi Nurhidayah ◽  
Sri Cahyo Wahyono ◽  
Simon Sadok Siregar
Keyword(s):  
Magnetic Field ◽  
Data Processing ◽  
Geophysical Methods ◽  
Mining Area ◽  
Magnetic Method ◽  
Contour Map ◽  
Total Magnetic Field ◽  
Qualitative And Quantitative ◽  
Qualitative Interpretation ◽  
The Earth

This research has been done in the mining area of andesite rock of Awang Bangkal village by using magnetic method. Magnetic method is one of the most common geophysical methods used for preliminary surveys on petroleum, earth, and mineral rock exploration. It is intended to determine the subsurface distribution in the area by performing qualitative and quantitative interpretations based on the magnetism value of the earth. The result of data processing using geosoft oasis montaj software shows that the total magnetic field anomaly is -807,3 to -361,7 nT. Qualitative interpretation is done by looking at the contour map of the anomaly, the result of upward continuation and the reduction to the poles. While the interpretation is done by making a modeling of the path that has been determined using mag2dc software. The model shows that the rocks that dominate the area are andesite rocks with their susceptibility value of 0.0992 to 0.2305 in SI units.

QUANTITATIVE INTERPRETATION OF VERTICAL MAGNETIC ANOMALIES OVER VEINS

Geophysics ◽  
1950 ◽  
Vol 15 (4) ◽  
pp. 667-686 ◽  
Author(s):  
Kenneth L. Cook
Keyword(s):  
Magnetic Field ◽  
Magnetic Anomaly ◽  
Magnetic Induction ◽  
Vertical Component ◽  
Magnetic Anomalies ◽  
Quantitative Interpretation ◽  
Magnetic Intensity ◽  
Magnetic Inclination ◽  
Magnetic North ◽  
The Magnetic Field

By using ordinary magnetic induction methods of analysis, Haalck, Heiland, and others have developed formulas which express the magnetic anomaly over a vertical or inclined vein of tabular shape as a function of the susceptibility, dimensions, shape, and disposition of the vein, and of the strength and direction of the earth’s magnetic field. On the basis of these fundamental formulas, other formulas for the vertical component of the magnetic field are derived in the present paper for such veins in intermediate northern magnetic latitudes. Special emphasis is given to the orientation of the veins relative to the magnetic north direction. Several families of vertical magnetic intensity curves for veins with different strikes and dips are given. All theoretical curves for veins striking magnetic north are plotted in terms of a parametric unit so that, once plotted, they can be used repeatedly in different districts, provided a proper multiplying factor is chosen for the observed curve. The importance of the transverse horizontal magnetization effect under certain conditions of orientation is demonstrated. It is shown mathematically that small vertical magnetic anomalies are to be expected for thin veins striking east and dipping south at an angle equal to, or approximately equal to, the complement of the angle of magnetic inclination.

scholarly journals Distribution of Iron Sand in The Widarapayung Coast Area at Regency of Cilacap Based on Magnetic Anomaly Data

2017 ◽  
Vol 6 (02) ◽  
pp. 97
Author(s):  
Sehah Allasimy ◽  
Sukmaji Anom Raharjo ◽  
Muhammad Andi Kurniawan
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Anomaly ◽  
Magnetic Anomalies ◽  
Research Area ◽  
Object Model ◽  
Intensity Data ◽  
Magnetic Intensity ◽  
A Value ◽  
Proton Precession Magnetometer ◽  
Sand And Gravel

Interpretation on the magnetic anomalies data has been done in the Widarapayung coast area, District of Binangun, Regency of Cilacap to identify distribution of iron sand. The acquisition of magnetic intensity data in this area has been done in December 2015 and May 2016 using Proton Precession Magnetometer (PPM) with type of GSM-19T. The research area extends on the geographic positions of 109.2501°BT – 109.2702°E and 7.6781°LS – 7.6986°S. Magnetic anomalies data modeling is done with using Mag2DC for Windows software so obtained some subsurface anomalous objects model. The anomaly object model having a value of magnetic susceptibility of 0.0093cgs unit is interpreted as iron sand interspersed with silt, clay, sand, and gravel from the alluvium formation. This formation is lain at a depth of 1.709 to 11.966m and a length of 1576.7m. The iron sand contained in this formation is estimated prospects for exploitation. Based on the interpretation results, alluvium formation is also found at a depth of 1.140 to 30.769m, which expected be composed of silt, clay, sand, and gravel with a magnetic susceptibility value of 0.0051cgs unit. The content of iron sand in this 2<sup>nd</sup> alluvium formation is expected to be relatively small.

scholarly journals Analisis Sebaran Mineral Logam Pada Sedimentasi Batuan Di Daerah Kertajadi, Cidaun, Kabupaten Cianjur, Jawa Barat Menggunakan Metoda Geomagnet

Wahana Fisika ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 37
Author(s):  
Rajab Basuki ◽  
Nanang Dwi Ardi ◽  
Mimin Iryanti
Keyword(s):  
Magnetic Anomaly ◽  
Mineral Exploration ◽  
Ferrous Metal ◽  
Magnetic Anomalies ◽  
Coastal Areas ◽  
Inversion Method ◽  
Quantitative Interpretation ◽  
West Java ◽  
Value Range ◽  
The Difference

Cidaun merupakan salah satu daerah pesisir pantai selatan yang terletak pada Kabupaten Cinajur Provinsi Jawa Barat. Salah satu kelebihan dari daerah pesisir pantai selatan Pulau Jawa adalah terdapat banyaknya mineral logam penghasil besi yang tersebar luas di sepanjang pesisir pantai. Oleh karena itu dilakukanlah eksplorasi untuk memetakan sebaran mineral logam yang ada di daerah Cidaun. Dalam melakukan eksplorasi mineral logam dibutuhkan suatu metode yang paling efektif yaitu eksplorasi geofisika dengan menggunakan metode geomagnet. Proses pengolahan data pada metode geomagnet dilakukan dengan menghitung nilai anomali magnetik dari medan magnetik total yang telah dilakukan koreksi terhadap koreksi harian dan koreksi IGRF. Kemudian dengan metode inversi data yang telah didapat dijadikan sebuah model. Selain itu dilakukan juga interpretasi kualitatif dan interpretasi kuantitatif. Interperetasi kualitatif dilakukan pada data yang telah dimodelkan menggunakan software surfer 11, apabila data tersebut terdapat anomali magnetik bernilai sangat tinggi yang berdekatan dengan nilai anomali magnetik bernilai rendah atau perubahan nilai anomali terjadi secara signifikan kemudian dilakukan proses interpretasi secara kuantitatif. Interpretasi kuantitatif pada penelitian ini dengan dilakukan deliniasi berupa proses sayatan pada perbedaan nilai anomali magnetik yang terjadi perubahan secara signifikan. Tahap selanjutnya data dari proses sayatan tersebut kemudian dilakukanlah pemodelan menggunakan software mag2dc untuk mengetahui sebaran mineral logam dapa daerah tersebut. Berdasarkan data yang telah diolah pada daerah Kertajadi, Cidaun, Kabupaten Cianjur, Jawa Barat dengan koordinat 698283 easting - 757162 easting dan 9180169 northing - 9171050 northing memiliki rentang nilai anomali magnetik -5 nT – 145 nT. Sedangkan nilai anomali magnetik pada daerah yang telah dilakukan proses sayatan memiliki rentang nilai 84.18 nT - 119.69 nT dengan nilai susptibilitas -0.041000 – 0.050001. Dari rentang nilai suseptibilitas tersebut diduga sebaran mineral yang yang memiliki nilai suseptibilitas positif merupakan bijih besi sedangkan yang bernilai negatif merupakan lempung dan endapan pasir. Dari hasil dari penelitian ini diharapkan data tersebut dapat dijadikan informasi dan referensi bagi masyarakat, peneliti lain dan pengusaha tambang dalam eksplorasi mineral logam.Cidaun is one of the coastal areas of the southern coast located in the district of West Java province Cinajur. One of the advantages of the southern coastal areas of Java is that there are many ferrous metal mineral producer widespread along the coast. Therefore, the exploration was undertaken to map the distribution of metallic minerals in the area Cidaun. In conducting metal mineral exploration required a most effective method is a geophysical exploration using geomagnetic methods. Data processing on geomagnetic method is done by calculating the value of the magnetic anomalies of the total magnetic field has a daily correction of correction and correction IGRF. Then, with the inversion method of data has been obtained serve as a model. The researcher also interpretation of qualitative and quantitative interpretation. Qualitative Interperetasi performed on the data that has been modeled using software surfer 11, when the inputs are very high-value magnetic anomalies adjacent to the value of the magnetic anomalies of low value or change in value of the anomaly occurred significantly later performed quantitative interpretation process. Quantitative interpretation in this study conducted a process of delineation of the incision on the difference in magnetic anomaly change significantly. The next stage of the data are then perform the incision process modeling using software mag2dc to determine the distribution of metallic minerals onshore areas. Based on the data that has been processed in the region Kertajadi, Cidaun, Cianjur, West Java coordinate 698283 easting - 757162 easting and 9180169 northing - 917105 northing and has a value range of magnetic anomaly -5 nT - 145 nT. While the value of magnetic anomalies in the area that has been carried out the process of incisions have a range of values 84.18 nT - 119.69 nT with susptibilitas value -0.041000 - 0.050001. Of the value range susceptibility is suspected distribution of minerals that have a positive susceptibility value is the iron ore which is negative while the clay and sand deposits. From the results of this study are expected data can be made of information and reference for the community, other researchers and mining company in mineral exploration.

scholarly journals An improved space domain algorithm for determining the 3-D structure of the magnetic basement

2019 ◽  
Vol 41 (1) ◽  
pp. 69-80
Author(s):  
Nguyen Thi Thu Hang ◽  
Erdinc Oksum ◽  
Le Huy Minh ◽  
Do Duc Thanh
Keyword(s):  
Magnetic Anomaly ◽  
Science And Technology ◽  
Three Dimensional ◽  
Magnetic Anomalies ◽  
Magnetic Data ◽  
Marine Science ◽  
Euler Deconvolution ◽  
The Earth ◽  
Magnetic Basement ◽  
Basement Structures

The paper presents an improved algorithm based on Bhaskara Rao and Ramesh Babu’s algorithm to invert magnetic anomalies of three-dimensional basement structures. The magnetic basement is approximated by an ensemble of juxtaposed vertical prisms whose bottom surface coincides with Curie surface with the known depth. The computer program operating with the proposed algorithm is built in Matlab environment. Test applications show that the proposed method can perform computations with fast and stable convergence rate where the results also coincide well with the actual model structure. The effectiveness of the method is demonstrated by inverting magnetic anomalies of the southeast part of Vietnam continental shelf. The calculated magnetic basement relief of the study area provides useful additional information for studies in the aim of dealing with the geological structure of the area.References Beiki M., 2010. Analytic signals of gravity gradient tensor and their application to estimate source location, Geophysics, 75(6), i59–i74.Bui C.Q. (chief author), Le T., Tran T. D., Nguyen T. H., Phi T.T., 2007. Map of deep structure of the Earth’s crust, Atlas of the characteristics of natural conditions and environment in Vietnam’s waters and adjacent region. Publisher of Science and Technology, Ha Noi. Do D.T., Nguyen T.T.H., 2011. Atempt the improvement of inversion of magnetic anomalies of two dimensional polygonal cross sections to determine the depth of magnetic basement in some data profile of middle off shelf of Vietnam. Journal of Science and Technology, Vietnam Academy of Science and Technology, 49(2), 125–132.Do D.T., 2013. Study for application of 3D magnetic and gravity method to determine density contribution of basement rock and depth of magnetic basement on Vietnam’s shelf for oil research and prospecting Vietnam National University, Hanoi, Project code QG-11-04. Keating P. and Pilkington M., 2000, Euler deconvolution of the analytic signal, 62nd Annual International Meeting, EAGE, Session P0193.Keating P., Zerbo L., 1996. An improved technique for reduction to the pole at low latitudes, Geophysics, 61, 131–137.Le H.M., Luu V.H., 2003. Preliminary interpretation of the magnetic anomalies of the Eastern Vietnam sea and adiacent regions. J.  Sci. of the Earth, 25(2), 173–181. Mai T.T., Pham V.T., Dang V.B., Le D.B., Nguyen B., Le V.D., 2011. Characteristics of Pliocene - Quaternary geology and Geoengineering in the Center and Southeast parts of Continental Shelf of Vietnam. J.  Sci.  of the Earth, 33(2), 109-118.Mushayandebvu M.F., Lesur V., Reid A.B., Fairhead J.D., 2004. Grid Euler deconvolution with constraints for 2D structures, Geophysics, 69, 489–496.Nguyen N.T., Bui V.N., Nguyen T.T.H., Than D.L., 2014a. Application of power density spectrum of magnetic anomaly to estimate the structure of magnetic layer of the earth crust in the Bac Bo gulf. Journal of Marine Science and Technology, 14(4A), 137–148.Nguyen N.T., Bui V.N., Nguyen T.T.H., 2014b. Determining the depth to the magnetic basementand fault systems in Tu Chinh - Vung May area  by magnetic data interpretation. Journal of Marine Science and Technology, 14(4A), 16–25.Nguyen T.T.H., Pham T.L., Do D.T., Le H.M., 2018. Improving algorithm of determining the coordinates of the vertices of the polygon to invert magnetic anomalies of two-dimensional basement structures in space domain, Journal of Marine Science and Technology (preparing to print).Parker R.L., 1973. The rapid calculation of potential anomalies, Geophys. J. Roy. Astron. Soc, 31, 447–455. Pilkington M., Gregotski M.E., Todoeschuck J.P., 1994. Using fractal crustal magnetization models in magnetic interpretation, Geophysical Prospecting, 42, 677–692.Pilkington M., 2006. Joint inversion of gravity and magnetic data for two-layer models, Geophysics, 71, L35–L42.Rao D.B., Babu N.R., 1993. A fortran 77 computer program for three dimensional inversion of magnetic anomalies resulting from multiple prismatic bodies, Computer & Geosciences, 19(8), 781–801.Tanaka A., Okubo Y., Matsubayashi O., 1999. Curie point depth based on spectrum analysis of the magnetic anomaly data in East and Southeast Asia, Tectonic Pphysics, 306, 461–470.Thompson D.T., 1982. EULDTH – A new technique for marking computer-assisted depth estimates from magnetic data, Geophysics, 47, 31–37.Vo T.S., Le H.M., Luu V.H., 2005. Determining the horizontal position and depth of the density discontinuties in Red River Delta by using the vertical derivative and Euler deconvolution for the gravity anomaly data, Vietnam. Journal of Geology, Series A, 287(3–4), 39–52.  Werner S., 1955. Interpretation of magnetic anomalies of sheet-like bodies, Sveriges Geologiska Undersokning, Series C, Arsbok, 43, 6.Xu S.Z., 2006. The integral-iteration method for continuation of potential fields, Chinese journal of geophysics (in Chinese), 49(4), 1176–1182.Zhang C., Huang D.N., Zhang K., Pu Y.T., Yu P., 2016. Magnetic interface forward and inversion method based on Padé approximation, Applied Geophysics, 13(4), 712–720.CCOP, 1996. Magnetic anomaly map of East Asia, scale 1:4.000.000, Geological survey of Japan and Committee for co-ordination of joint prospecting for mineral resources in asian offshore areas.

DERIVATION OF MAGNETIC AND GRAVITATIONAL QUANTITIES BY SURFACE INTEGRATION

Geophysics ◽  
1949 ◽  
Vol 14 (2) ◽  
pp. 133-150 ◽  
Author(s):  
D. C. Skeels ◽  
R. J. Watson
Keyword(s):  
Magnetic Field ◽  
Horizontal Plane ◽  
Plane Surface ◽  
Vertical Component ◽  
Magnetic Anomalies ◽  
Magnetic Intensity ◽  
Artificial Data ◽  
The Earth ◽  
Surface Integration ◽  
Derivatives Of

In an earlier paper by one of the authors, it was pointed out that if the vertical component of a gravitational or magnetic field is known over a horizontal plane surface of sufficient extent, all other components and derivatives of the field can theoretically be calculated by surface integration of the vertical component. In this paper, examples are given to show that within certain limits such calculations are not only theoretically possible but practically so. Examples are given of the calculations of curvatures from observed gradients and of horizontal magnetic intensity from observed vertical intensity, and the calculated values are compared with those obtained by observation. Examples are also given, based on artificial data, of the calculation of plumb‐line deflections from gravity and of the calculation of magnetic anomalies at a given elevation above the earth from data obtained at the surface. The purpose of these calculations is to demonstrate the nonindependence of the various derivatives of gravitational and magnetic potential.

Intermediate‐scale magnetic anomalies of the Earth

Geophysics ◽  
1985 ◽  
Vol 50 (12) ◽  
pp. 2817-2830 ◽  
Author(s):  
J. Arkani‐Hamed ◽  
D. W. Strangway
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Anomaly ◽  
Correlation Coefficients ◽  
Sedimentary Basins ◽  
Magnetic Anomalies ◽  
The Earth ◽  
Asymmetric Component ◽  
Anomaly Map ◽  
Well Correlation

Four separate magnetic anomaly maps of the earth are derived from magnetometer satellite data acquired at dawn and at dusk using two different altitude ranges. The magnetic anomalies on the two dawn maps (or dusk maps) are well correlated for spherical harmonics of degree less than 51, suggesting that the time varying external magnetic field and leveling noise have negligible effects on these harmonics. Dawn and dusk maps have an appreciable asymmetric component for harmonics of degree n ⩽ 5 and n = 15 and 17, arising from the quasi‐stable external magnetic field. Dawn‐dusk covariant harmonics of degree [Formula: see text] with signal‐to‐noise ratios greater than 1.5 correlate well. Correlation coefficients are higher than 0.75, implying that these harmonics can be repeatably derived. A global scalar magnetic anomaly map is derived based on these harmonics. The map is then converted to a magnetic susceptibility anomaly map by an inversion technique. The susceptibility anomalies delineate the ocean‐continent differences as well as the boundaries of tectonic provinces, modern uplifts, crustal rifts, and sedimentary basins.

scholarly journals Upward Continuation of Subsurface Anomalies Utilizing Magnetic Data in The Bedadung Watershed, Jember City

2016 ◽  
Vol 16 (2) ◽  
pp. 69
Author(s):  
Yudhistira Adi Nugraha ◽  
Puguh Hiskiawan ◽  
Supriyadi Supriyadi
Keyword(s):  
Data Analysis ◽  
Magnetic Anomaly ◽  
Research Area ◽  
Magnetic Data ◽  
Magnetic Method ◽  
Magnetic Characteristics ◽  
Data Input ◽  
Contour Map ◽  
Upward Continuation ◽  
Subsurface Material

Magnetic method is a geophysics method to determine the kind of subsurface material in certain depth by identifying the magnetic characteristics of rock based on the value of magnetic suspetibility. The data analysis described the subsurface anomaly using upward continuation filter. It separated local anomaly and regional anomaly by lifting research area in certain elevation. The raw data research was the total of magnetics data around Bedadung watershed, Jember. It was proceeded to obtaine magnetic anomaly curve on 5 line in contour map. It was digitalized and use as data input of magpick and upward continuation filter program. Upward continuation program was conducted using variation of area elevation in each track from 1 m up to 30 m. magnetic anomaly from this program is compared to magpick result showed that the magnetic anomaly curve on each line have good suitability with the accuracy 0,93%. Therefore, the continuation program become the alternative in magnetic data processing.

scholarly journals INTERPRETASI JENIS BATUAN MENGGUNAKAN METODE GEOMAGNETIK PADA DAERAH TERAKUMULASINYA AIR TANAH DI BENA AMANUBAN SELATAN

2018 ◽  
Vol 3 (2) ◽  
pp. 126-131
Author(s):  
Yohanes Takaeb ◽  
Hadi Imam Sutaji ◽  
Bernandus Bernandus
Keyword(s):  
Field Data ◽  
Magnetic Anomalies ◽  
Quantitative Interpretation ◽  
Rock Types ◽  
Qualitative Interpretation ◽  
Rock Structure ◽  
Proton Precession Magnetometer ◽  
Clay Rocks ◽  
Study Sites ◽  
Area Data

Abstrak Telah dilakukan penelitian interpretasi jenis batuan menggunakan metode geomagnetik pada daerah terakumulasinya air tanah di Bena Amanuban Selatan. Tujuan penelitian ini untuk menentukan pemetaan anomali magnetik bawah permukaan dan pola penyebaran batuan di sekitar daerah terakumulasinya air tanah. Akuisisi data menggunakan  Proton Precession Magnetometer (PPM) tipe GSM–19T. Hasil pengukuran data lapangan berupa nilai medan magnet total dan variasi harian yang diolah serta diinterpretasikan secara kualitatif dan kuantitatif. Interpretasi kualitatif menunjukkan tiga pola anomali, yaitu anomali tinggi, sedang dan rendah. Anomali tinggi (sekitar 105 nT sampai 140 nT) pada bagian selatan dan barat daya diduga berupa batuan lempung dan batugamping. Anomali sedang (sekitar 70 nT sampai <105 nT) yang mendominasi lokasi penelitian diduga batuan lempung dan batu pasir. Anomali rendah (sekitar 40 nT sampai <70 nT) di bagian timur diduga batu gamping dan batu pasir. Interpretasi kuantitatif menunjukan struktur batuan yang diduga akuifer yaitu batu pasir memiliki suseptibilitas 6.7 x 10-5 – 3.56 x10-4 pada kedalaman 22.8 m serta batugamping yang bersifat meluluskan air dengan suseptibilitas 5.792 x 10-3 – 9.247 x 10-3 dengan kedalaman 75 m. Selain kedua batuan tersebut, terdapat batuan lempung dengan suseptibilitas 7.28 x 10-4 – 1.063 x 10-3 di kedalaman 13.8 m. Kata kunci: Metode geomagnetik, suseptibilitas, akuifer. Abstract An interpretation of rock types has been done using geomagnetic method in the area of ​​accumulated groundwater in Bena Amanuban Selatan. The purpose of this study was to determine the mapping of subsurface magnetic anomalies and the pattern of rock distribution around the accumulated groundwater area. Data acquisition using Proton Precession Magnetometer (PPM) type GSM-19T. The results of field data measurements in the form of total magnetic field value and daily variations are processed and interpreted qualitatively and quantitatively. Qualitative interpretation shows three patterns of anomalies, namely high anomalies, moderate and low. High anomalies (about 105 nT to 140 nT) in the south and southwest are thought to be clay and limestone. Moderate anomalies (about 70 nT to <105 nT) that dominate the study sites are suspected clay and sandstone. Low anomalies (about 40 nT to <70 nT) in the eastern part are suspected of limestone and sandstone. Quantitative interpretation shows the suspected aquifer rock structure of sandstone has a susceptibility of 6.7 x 10-5 – 3.56 x10-4 at a depth of 22.8 m as well as a water-grinding limestone with the susceptibility of 5.792 x 10-3 – 9.247 x 10-3 with a depth of 75 m. In addition to these two rocks, there are clay rocks with the susceptibility of 7.28 x 10-4 – 1.063 x 10-3 at depth of 13.8 m. Keywords: Geomagnetic method, susceptibility, aquifer.

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