scholarly journals Modeling Folding Zone in Kedungsari Compassionate Area Kulon Progo Yogyakarta with Gravity Method

Author(s):  
Maya Luthfiya ◽  
Thaqibul Fikri Niyartama

This study aims to determine the condition of subsurface by doing interpretation quantitatively. Quantitative interpretation is done by modeling to determine the shape and boundary of the anomaly. The gravity data reduction is done up to Complete Bouguer Anomaly (CBA) value is obtained. The complete Bouguer anomaly is brought to horizontal plane reduction and separation of local and regional anomalies using the upward continuation method. 2.5 modelling has been made from local anomaly data to illustrate the subsurface condition of the research area more clearly. The result shows R1 density value of 2.55 g / m3 which is a limestone and R2 2,8902 g/m3 which is andesitic rock. The position of the anticline axis is at coordinates 49 S 9128700 N 409844.9 E, while the syncline axis is at coordinates 9129037 N 408694,1 E.

2012 ◽  
Author(s):  
Nasrun Balulu

A geophysical survey using gravity method was carried out in Muria  volcano. This research aimed to interpret the subsurface geology condition of the research area based on gravity data analysis. Research area is (47,6 x 45) km2    with 222 observation  points. Gravitymeter  LaCoste &amp; Romberg type G-1118 MVR was used to    measure the  gravity field, and differential method of Global Positioning System (GPS) was used to measure the position and elevation.<br /><br />Data processing was performed to gain complete Bouguer  anomaly of both residual and  regional. Bouguer density using graphical method resulted to the value of 2.67 gr/cm3.  Transformation to a horizontal plane was performed obtain by using equivalent mass method with horizontal level’s height of 1602 meters beyond the spheroid reference and equivalent The separation of regional anomaly and residual  anomaly  was  generated  through  upward  continuation  method  and  resulted  to  regional anomaly in the height of  15000 meters up the spheroid reference. The residual anomaly acquired by subtract the regional anomaly toward the complete Bouguer anomaly in a horizontal plane.<br /><br />The subsurface modelling of Muria  volcano and its surrounding was acquired from  Grav2DC for Windows. The result shows that Muria volcano and its surrounding was regionally controlled by rock resulted from volcanic processes as lava (density 2,91 gr/cm3). This volcanic rock due to the gravity collapse performed a caldera filled by andesit (density 2,58 gr/cm3). Another rock which is deposited in  Muria  volcano  are  tuff  from  Muria  Tuff  (density  2,4  gr/cm3),  tuff  sandstone  from  Patiayam formation (density 2,5 gr/cm3),  limestone from Bulu formation (density 2,7 gr/cm3), and  limestone from Ngrayong formation (density 2,8 gr/cm3).<br /><br />Keywords:Bouguer anomaly, Regional anomaly, Residual anomaly,  Modeling, Subsurface stracture.<br /><br />


2020 ◽  
Vol 4 (2) ◽  
pp. 62-76
Author(s):  
Shiska Yulistina

In general, Manokwari has a geological structure that is in the form of a folding area found in the highlands of the mountains. Among the creases, there is a fault up and the fault down. In coastal or marine areas found many reefs and corals. The study of gravity was conducted in the Manokwari area of West Papua with the aim to know the subsurface geological structures based on FHD (First Horizontal Derivative), SVD (Second Vertical Derivative) and 2.5D Forward Modeling on the residual anomaly maps of the study area. The results showed that the research area has Bouguer Anomaly value ranged from 4 mGal to 96 mGal with the low anomaly at the left side of the research area lengthwise relatively in north-west to south-east direction, the middle-value anomaly spreads in the west-east area of research area, high anomaly scattered in the northern part of the research area. The results of the 2.5D subsurface modeling and the SVD and FHD analysis indicated the presence of a Thrust Fault on the C-C’ cross-section, on the B-B’ cross-section there is a Diorite Lembai intrusion with the density value is 2.75 gr/cc, whereas the A-A' cross-section which intersects with Sorong fault were not found any fault or rock intrusion based on observed gravity data of the research area.


2016 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Anjar Pranggawan Azhari ◽  
Sukir Maryanto ◽  
Arief Rachmansyah

Gravity survey has been acquired by Gravimeter Lacoste &amp; Romberg G-1035 at Blawan-Ijen geothermal area. It was a focusing study from previous research. The residual Bouguer anomaly data was obtain after applying gravity data reduction, reduction to horizontal plane, and upward continuation. Result of Bouguer anomaly interpretation shows occurrence of new faults and their relative movement. Blawan fault (F1), F2, F3, and F6 are normal fault. Blawan fault is main fault controlling hot springs at Blawan-Ijen geothermal area. F4 and F5 are oblique fault and forming a graben at Banyupahit River. F7 is reverse fault. Subsurface model shows that Blawan-Ijen geothermal area was dominated by the Ijen caldera forming ignimbrite (ρ1=2.670 g/cm3), embedded shale and sand (ρ2=2.644 g/cm3) as Blawan lake sediments, magma intrusion (ρ3=2.814 g/cm3 &amp; ρ7=2.821 g/cm3), andesite rock (ρ4=2.448 g/cm3) as geothermal reservoir, pyroclastic air fall deposits (ρ5=2.613 g/cm3) from Mt. Blau, and lava flow (ρ6=2.890 g/cm3).


2020 ◽  
Vol 10 (01) ◽  
pp. 65
Author(s):  
Sorja Koesuma ◽  
Mela Budiani Septianingsih ◽  
Budi Legowo

<p>Information about the eastern side subsurface stones of Mount Lawu regarding geothermal potential is limited. This research was conducted to provide information regarding geothermal potential in those area by using the gravity method. We did a 18 sites of gravity surveys in eastern flank of Mount Lawu where located in Magetan regency, Ngawi regency and Sragen regency, East Java. The principle of this method is to measure the earth's gravity field, then the value of gravity is corrected by some gravity corrections, i.e. height, tide, drift, normal gravity, free-air, Bouguer and terrain corrections. The Complete Bouguer Anomaly (CBA) shows the formation that related to the rock formation in the subsurface of Mount Lawu. Based on CBA modelling we found that in the eastern flank of Mount Lawu contains of tuff and breccia of volcanic rocks, breccia Jabolarangan and tuff Jabolarangan, lava andesite, igneous rock (pumice), and sedimentary rocks in the form of sandstone and clay. We found a fault structure on six tracks of a research area. Otherwise, we estimated that there is a geothermal potential on the southeast side of the research area</p>


2020 ◽  
Vol 4 (2) ◽  
pp. 47-61
Author(s):  
Roy Bryanson Sihombing ◽  
Rustadi Rustadi

Research has been conducted in Kepahiang area using gravity data with the aim of identify faults based on analysis of the Second Vertical Derivative (SVD) and interpreting structure sub-surface of the based on 3D inverse modelling from Bouguer anomaly and residual anomaly. The research area have an Bouguer anomaly between 38 mGal - 74 mGal, where the high Bouguer anomaly value has a value range of 63,2 mGal - 74 mGal located in the southwest direction of the research area. Whereas the low Bouguer anomaly value has a range of values 38 mGal - 47 mGal located in the north of the research area. To know the existence of fault structure in research area, conducted filtering Second Vertical Derivative (SVD) on the map Bouguer anomaly, regional and residual. The structure faulting is shown with contour of zero and between the contours of high and low. From the analysis of SVD complete anomaly Bouguer and SVD residual anomaly there are 8 (eight) faulting, while from SVD regional anomaly there are 4 (four) fault. 3D inversion modeling of the residual anomaly was done to prove the existence of the fault analyzed based on filtering Second Vertical Derivative (SVD). Based on the results of inversion 3D residual anomaly been gained one (1) reservoir in a northern direction research area and two (2) in the direction of west the research area by a contrast the density of -0,0719356 gr/cc until -0,236053 gr/cc with a depth of 0 meters up to 4.705 meters.


2005 ◽  
Vol 1 (1) ◽  
pp. 21-24
Author(s):  
Hamid Reza Samadi

In exploration geophysics the main and initial aim is to determine density of under-research goals which have certain density difference with the host rock. Therefore, we state a method in this paper to determine the density of bouguer plate, the so-called variogram method based on fractal geometry. This method is based on minimizing surface roughness of bouguer anomaly. The fractal dimension of surface has been used as surface roughness of bouguer anomaly. Using this method, the optimal density of Charak area insouth of Hormozgan province can be determined which is 2/7 g/cfor the under-research area. This determined density has been used to correct and investigate its results about the isostasy of the studied area and results well-coincided with the geology of the area and dug exploratory holes in the text area


1997 ◽  
Vol 23 (10) ◽  
pp. 1063-1070 ◽  
Author(s):  
W.E. Featherstone ◽  
M.C. Dentith
Keyword(s):  

2018 ◽  
Vol 7 (1) ◽  
pp. 94
Author(s):  
Anatole Eugene Djieto Lordon ◽  
Mbohlieu YOSSA ◽  
Christopher M Agyingi ◽  
Yves Shandini ◽  
Thierry Stephane Kuisseu

Gravimetric studies using the ETOPO1-corrected high resolution satellite-based EGM2008 gravity data was used to define the surface extent, depth to basement and shape of the Mamfe basin. The Bouguer anomaly map was produced in Surfer 11.0. The Fast Fourier Transformed data was analyzed by spectral analysis to remove the effect of the regional bodies in the study area. The residual anomaly map obtained was compared with the known geology of the study area, and this showed that the gravity highs correspond to the metamorphic and igneous rocks while the gravity lows match with Cretaceous sediments. Three profiles were drawn on the residual anomaly map along which 2D models of the Mamfe basin were drawn. The modeling was completed in Grav2dc v2.06 software which uses the Talwini’s algorithm and the resulting models gave the depth to basement and the shape of the basement along the profiles. After processing and interpretation, it was deduced that the Mamfe basin has an average length and width of 77.6 km and 29.2 km respectively, an average depth to basement of 5 km and an overall U-shape basement. These dimensions (especially the depth) theoretically create the depth and temperature conditions for petroleum generation. 


2016 ◽  
Vol 3 (01) ◽  
pp. 10 ◽  
Author(s):  
Jarot Purnomo ◽  
Sorja Koesuma ◽  
Mohtar Yunianto

<span>It has been done a research about separation of regional-residual anomaly in Gravity method. <span>This research compares the result of three methods i.e. moving average method, polynomial <span>method, and inversion method. The computer program is created using a computer programming <span>Matlab 7. From three methods that have been made, the separation results are compared with<br /><span>results of separation by using Upward Continuation method. From the results of these <span>comparisons will be available an excellent program of regional-residual anomali separation. The <span>results show that in polynomial method of the order 4 obtained similar contour to the separation <span>by Upward Continuation Software. So that the output of this separation will be treated again <span>with Grav2DC software. The output of this software is the density of rock Grav2DC of the study<br /><span>area. Processing results obtained the minimum error of 1.85% for the separation by polynomial <span>method, while for the method of Upward Continuation obtained minimum error of 2.22%. The <span>results obtained show that the separation of regional-residual anomali by polynomial method is <span>similar to separation by Upward Continuation method.</span></span></span></span></span></span></span></span></span></span></span></span><br /></span>


2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Gumilar Utamas Nugraha ◽  
Karit Lumban Goal ◽  
Lina Handayani ◽  
Rachmat Fajar Lubis

Lineament is one of the most important features showing subsurface elements or structural weakness such as faults. This study aims to identify subsurface lineament patterns using automatic lineament in Citarum watershed with gravity data. Satellite gravity data were used to generate a sub-surface lineament. Satellite gravity data corrected using Bouguer and terrain correction to obtain a complete Bouguer anomaly value. Butterworth filters were used to separate regional and residual anomaly from the complete Bouguer anomaly value. Residual anomaly gravity data used to analyze sub-surface lineament. Lineament generated using Line module in PCI Geomatica to obtain sub-surface lineament from gravity residual value. The orientations of lineaments and fault lines were created by using rose diagrams. The main trends observed in the lineament map could be recognized in these diagrams, showing a strongly major trend in NW-SE, and the subdominant directions were in N-S. Area with a high density of lineament located at the Southern part of the study area. High-density lineament might be correlated with fractured volcanic rock upstream of the Citarum watershed, meanwhile, low-density lineament is associated with low-density sediment. The high-density fracture might be associated with intensive tectonics and volcanism.


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