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

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.

Author(s):  
Muhammad Sehah ◽  
Sukmaji Anom Raharjo ◽  
Azmi Risyad

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.


2017 ◽  
Vol 7 (2) ◽  
pp. 71 ◽  
Author(s):  
Sehah Allasimy ◽  
Sukmaji Anom Raharjo ◽  
Iska Andriyanto

<p class="AbstractText">Exploration of the spread of iron sand on the eastern coastal of Binangun District in Cilacap Regency has been conducted using the magnetic surveys. The magnetic data acquisition was conducted in April 2017. The total magnetic field data obtained is processed, so that can be obtained the local magnetic anomaly data. The modeling of the local magnetic anomaly data is performed on the trajectory of AB that extending from the position point of 109,274698° E and 7.686620° S to 109.2296195° E and 7.689099° S so that obtained various model of the subsurface anomalous objects. Interpretation on the subsurface anomalous objects is done to estimate the types of rocks and their formations based on the magnetic susceptibility value of each object which supported by the geological information of the research area. Based on the interpretation results to be obtained two layers of subsurface rocks that can be estimated as the iron sand that coexists with silt dan clay derived from the alluvium formation. The first rock has a length of 1238.2 meters, a depth of 1.709 – 20.513 meters, and a magnetic susceptibility value of 0.0183 cgs unit. The second rock has a length of 643.055 meters, a depth of 16.524 – 34.188 meters, and a magnetic susceptibility value of 0.0174 cgs unit. The results of this research are also supported by the results of geoelectric data interpretation, where the iron sand that coexists with silt and clay is found at a depth of 9.42 – 19.48 meters with a resistivity value of 52.99 Ωm at Geo-1 point; and a depth of 10.56 – 22.20 meters with resistivity value of 49,03 Ωm at Geo-2 point. Based on the results of of this research, the eastern coastal area of Binangun District is estimated to contain potentially iron ore and economically is a prospect for exploitation.</p>


2021 ◽  
Vol 13 (1) ◽  
pp. 26
Author(s):  
Muhammad Yanis ◽  
Aprilla Hasibuan Anggini ◽  
Faisal Abdullah ◽  
Muzakir Zainal ◽  
Marwan Abubakar

The Geophysical method is operated by using physical parameters above the surface to estimate the subsurface structures. In data interpretation, all 3D surveys, i.e., magnetic, gravity, magnetotelluric, and airborne, are required for geographical conditions in the research area. In a large area, global DEM data is used to explain the field condition, but for local measurement, the data is not efficient due to low resolution (15-30 m/px). This research uses UAV technology to produce a high-resolution topography in local Geophysical measurement (500 x 600 m). The survey was conducted to map the coal structure in the subsurface. UAV data were also compared to SRTM (30 m/px) and DEMNAS (8 m/px) as global topography. Based on data processing, the UAV topographic was have a high resolution of 2.5 cm/px. Comparison of UAV and magnetic data are able to explain a good condition of field measurement than a global DEM data, even in a relatively small area; outcrops of the coal (50x50 m) can show a good differences contrast of topography. Based on data analysis, we can conclude that UAV technology can interpret the geophysical data measured in a local area.Keywords: UAV, SRTM, Topography, Geophysical Interpretation.Metode Geofisika bekerja dengan memanfaatkan parameter fisis diatas permukaan untuk pendugaan struktur bawah permukaan. Dalam tahapan interpretasi data, semua pengukuran 3D Geofisika; magnetic, gravity, magnetotelluric, dan airbone sangat membutuhkan keadaan geografis lapangan. Pada area yang luas, data DEM global digunakan untuk menjelaskan deskripsi lapangan, namun untuk pengukuran dekat permukaan yang bersifat lokal, data ini tidaklah efesien, karena resolusi yang relative rendah (15 – 30 m/px). Kami menggunakan teknologi UAV untuk menghasilkan topografi resolusi tinggi pada area pengukuran Geofisika dengan luas 500 x 600 m, yang disurvei untuk pemetaan batubara dibawah permukaan. Data UAV juga dibandingkan dengan topografi global SRTM (30 m/px) dan DEMNAS (8 m/px). Hasil pengolahan data menunjukkan data UAV menghasilkan topografi dengan resolusi 2.5 cm/px. Hasil overlay UAV dengan Geofisika magnetik mampu menjelaskan deskripsi lapangan dengan sangat baik dibandingkan DEM global, bahkan pada area yang relative kecil seperti singkapan batuabara (50x50 m) dapat menunjukkan keadaan perbedaan topografi dengan kontras. Berdasarkan data analysis, topografi UAV sangat potensial digunakan untuk interpretasi data Geofisika dekat permukaan yang diukur pada area yang relative lokal.Kata kunci: UAV, SRTM, Topografi, Interpretasi Geofisika.


Author(s):  
Muhammad Irsyad ◽  
Sutrisno Sutrisno ◽  
Dwi Haryanto

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.


2015 ◽  
Vol 5 (02) ◽  
pp. 80 ◽  
Author(s):  
Sukmaji Anom Raharjo ◽  
Sehah S

<p class="AbstractText">The magnetic survey had been conducted in Village of Cipari, District of Cipari, Region of  Cilacap to interpret to the location of the oil seepage source rock. Boundary of the research area is 108.75675°E – 108.77611°E and 7.42319°S – 7.43761°S. The observed total magnetic data is corrected and reducted to obtain the local magnetic anomaly data. The local magnetic anomaly data is applied to model the subsurface bodies anomalies based on the Mag2DC for Windows software. With be supported the geological information, the some bodies anomalies are interpreted as the basaltic igneous rock (c = 0.0051), the alternately of sandstone and claystone and insert of marl from Halang Formation (c = 0.0014), the breccia from Kumbang Formation (c = 0.0035), the alternately of sandstones and claystone with insert of marl and breccia from Halang Formation (c = 0.0036), the claystone from Tapak Formation (c = 0.0015), the alternately of sandstones and claystone with insert of marl and compacted breccia from Halang Formation (c = 0.0030), and the alternately of sandstone and claystone from   Halang Formation (c = 0.0020). The plantonic foraminifer fossils as resources of oil seepage are estimated in the sedimentaries rocks, where the oil flows from those rocks into the         reservoir (source rock). Based on the interpretation results, the source rock is above basaltic igneous rock with the approximate position is 108.76164°W and 7.43089°S; and the depth is 132.09 meters below the average topographic.</p>


2017 ◽  
Vol 4 (02) ◽  
pp. 171
Author(s):  
Sehah S ◽  
Sukmaji Anom Raharjo ◽  
Adi Chandra

<p>The Estimation of coal bituminous depth in Village of Banjaran, District of Salem, Regency of Brebes based on magnetic anomaly data has been done. The Village of Banjaran is located in the geology basin which called as Bentarsari Basin. The activities stages that carried out in this research include of magnetic data acquisition in the field, data processing, and interpretation. The interpretation of the anomalies data is done through the modeling using the Mag2DC for Window software on the local magnetic anomalies data. Based on this modeling results, then obtained six anomalous objects that can be interpreted as the subsurface rocks in the research area, which consists of sediments of gravel, sand, clay, and silt ( = 0.0020 cgs units); tuff and tuffaceous sandstone ( = 0.0069cgs units); andesite breccia, tuff, and tuffaceous sandstone ( = 0.0085cgs units); solid andesite breccia which not layered ( = 0.0115 cgs units); coarse sandstones, limestones, and sandy marl ( = 0.0109cgs units); andesite sandstone that layered with claystone and thin insertions of new coal bituminous alternately ( = 0.0008cgs units). Based on the modeling results and the geological information of this research area, it can be estimated that the coal bituminous found in the Kaliglagah formation, with its depths ranging between 104.48 m – 505.97m, and the value of the magnetic susceptibility is 0.0008 cgs units.</p>


2021 ◽  
Vol 67 (7) ◽  
pp. 2199-2206
Author(s):  
N.A. Zakaria ◽  
S.H.M. Yusoff ◽  
N.A.M. Rizal ◽  
N.S.A. Hamid ◽  
M.H. Hashim ◽  
...  

2018 ◽  
Vol 14 (2) ◽  
pp. 15-28
Author(s):  
A A ALABI ◽  
O OLOWOFELA

Airborne magnetic data covering geographical latitudes of 7000‟N to 7030‟N and longitudes of 3 30′E to 4 00′E within Ibadan area were obtained from Nigeria Geology Survey Agency. The data were ana-lyzed to map the sub surface structure and the source parameters were deduced from the quantitative and qualitative interpretation of magnetic data. The upward continuation technique was used to de-emphasize short – wavelength anomaly while the depth to magnetic sources in the area was deter-mined using local wavenumber technique, the analytic signal was also employed to obtain the depths of the magnetic basement. Analysis involving the local wavenumber, upward continuation and appar-ent magnetic susceptibility techniques significantly improves the interpretation of magnetic data in terms of delineating the geological structure, source parameter and magnetic susceptibility within Iba-dan area.. These depth ranges from 0.607km to 2.48km. The apparent susceptibility map at the cut-off wavelength of 50 m ranges from -0.00012 to 0.00079 which agree with the susceptibility value of some rock types; granite gneiss, migmatite biotite gneiss, biotite muscovite granite, hornblende granite, quartz and schists. The result of the local wavenumber suggests variation along the profiles in the surface of magnetic basement across the study area.


2018 ◽  
Vol 93 (5) ◽  
pp. 553-564 ◽  
Author(s):  
R. Umar ◽  
◽  
S. F. Natasha ◽  
S. S. N. Aminah ◽  
K. N. Juhari ◽  
...  

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