scholarly journals Preliminary Study: Identifying the Heat Source of Hot spring Discovery at Non-Volcanic Region with Gravity Method

2021 ◽  
Vol 873 (1) ◽  
pp. 012092
Author(s):  
Abi Mawalid ◽  
Andi Mardhotilla
Keyword(s):  
Heat Source ◽  
Hot Spring ◽  
Gravity Data ◽  
Geophysical Methods ◽  
Density Variation ◽  
Distribution Area ◽  
Gravity Method ◽  
Volcanic Region ◽  
Geological Information ◽  
Preliminary Study

Abstract Gravity method is one of the geophysical methods that’s using variation of gravity value caused by density variation of subsurface. Gravity method has been utilized for many purposes such as understanding the geological information about one area or understanding the subsurface structure. This study is using gravity method to identify the heat source from the geothermal manifestation (hot spring) which is located in the non-volcanic region in North Java. Gravity data was obtained from WGM 2012 satellite data that can be downloaded at BGI website and processed using Oasis Montaj software. Data processed using horizontal derivative method to enhance the boundaries resolution of the possibility geological structures location in the study area that is predicted to be the way of the heat source of hot spring manifestation. The result of this study shows that the heat source of the hot spring in Northern East Java is probably coming from Lasem Volcano’s heat source. The result can be proven by the similarity of the Bouguer Anomalies value between the Lasem Volcano region and the manifestations distribution area, which varies in 174-185 mGal. Besides that, Lasem Volcano is the closest volcano from the manifestation with a distance of approximately around 27 km.

scholarly journals Joint Gravity and Seismic Reflection Methods to Characterize the Deep Aquifers in Arid Ain El Beidha Plain (Central Tunisia, North Africa)

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1310
Author(s):  
Hajer Azaiez ◽  
Hakim Gabtni ◽  
Mourad Bédir
Keyword(s):  
Seismic Reflection ◽  
Large Scale ◽  
Seismic Analysis ◽  
Gravity Data ◽  
Geophysical Methods ◽  
Gravity Anomalies ◽  
Integrated Approach ◽  
Central Tunisia ◽  
Deep Aquifers ◽  
Advanced Analysis

Electric resistivity sounding and tomography, as well as electromagnetic sounding, are the classical methods frequently used for hydrogeological studies. In this work, we propose the development and implementation of an original integrated approach using the unconventional hydro–geophysical methods of gravity and seismic reflection for the fast, large–scale characterization of hydrogeological potential using the Ain El Beidha plain (central Tunisia) as an analogue. Extending the values of vintage petroleum seismic reflection profiles and gravity data, in conjunction with available geological and hydrogeological information, we performed an advanced analysis to characterize the geometry of deep tertiary (Oligocene and Eocene) aquifers in this arid area. Residual and tilt angle gravity maps revealed that most gravity anomalies have a short wavelength. The study area was mainly composed of three major areas: the Oued Ben Zitoun and Ain El Beidha basins, which are both related to negative gravity trends corresponding to low–density subsiding depocenters. These basins are separated by an important NE–SW trend called “El Gonna–J. El Mguataa–Kroumet Zemla” gravity high. Evaluation of the superposition of detected lineaments and Euler deconvolution solutions’ maps showed several NE–SW and N–S relay system faults. The 3D density inversion model using a lateral and vertical cutting plane suggested the presence of two different tectonic styles (thin VS thick). Results from the gravity analysis were in concordance with the seismic analysis. The deep Oligocene and Eocene seismic horizons were calibrated to the hydraulic wells and surrounding outcrops. Oligocene and Eocene geological reservoirs appear very fractured and compartmented. The faulting network also plays an important role in enhancing groundwater recharge process of the Oligocene and Eocene aquifers. Finally, generated isochron maps provided an excellent opportunity to develop future comprehensive exploration surveys over smaller and more favorable areas’ sub–basins.

Highly efficient density inversion of gravity data using nonlinear density polynomial fitting

Geophysics ◽  
2021 ◽  
pp. 1-34
Author(s):  
Guoqing Ma ◽  
Zongrui Li ◽  
Lili Li ◽  
Taihan Wang
Keyword(s):  
Weighting Function ◽  
Gravity Data ◽  
Real Life ◽  
Density Variation ◽  
Density Change ◽  
Inversion Method ◽  
Density Inversion ◽  
Perspective View ◽  
Polynomial Fitting ◽  
Polynomial Coefficients

The density inversion of gravity data is commonly achieved by discretizing the subsurface into prismatic cells and calculating the density of each cell. During this process, a weighting function is introduced to the iterative computation to reduce the skin effect during the inversion. Thus, the computation process requires a significant number of matrix operations, which results in low computational efficiency. We have adopted a density inversion method with nonlinear polynomial fitting (NPF) that uses a polynomial to represent the density variation of prismatic cells in a certain space. The computation of each cell is substituted by the computation of the nonlinear polynomial coefficients. Consequently, the efficiency of the inversion is significantly improved because the number of nonlinear polynomial coefficients is less than the number of cells used. Moreover, because representing the density change of all of the cells poses a significant challenge when the cell number is large, we adopt the use of a polynomial to represent the density change of a subregion with fewer cells and multiple nonlinear polynomials to represent the density changes of all prism cells. Using theoretical model tests, we determine that the NPF method more efficiently recovers the density distribution of gravity data compared with conventional density inversion methods. In addition, the density variation of a subregion with 8 × 8 × 8 prismatic cells can be accurately and efficiently obtained using our cubic NPF method, which can also be used for noisy data. Finally, the NPF method was applied to real gravity data in an iron mining area in Shandong Province, China. Convergent results of a 3D perspective view and the distribution of the iron ore bodies were acquired using this method, demonstrating the real-life applicability of this method.

scholarly journals Geology and geophysics at the archeological park of Vulci (central Italy)

2014 ◽  
Vol 57 (1) ◽  
Author(s):  
Marco Marchetti ◽  
Vincenzo Sapia ◽  
Adriano Garello ◽  
Donatella De Rita ◽  
Alessandra Venuti
Keyword(s):  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Cultural Heritage ◽  
Central Italy ◽  
Geophysical Methods ◽  
Archaeological Sites ◽  
Local Authorities ◽  
Resistivity Tomography ◽  
Geological Information ◽  
Geological Map

<p>The Vulci archeological site was object of interest by the Soprintendenza ai beni culturali dell’Etruria meridionale (Italian government department responsible for southern Etruria’s cultural heritage) since the beginning of the 20th century. In 2001, the Ministero dei Beni Culturali (Italian ministry of cultural heritage) along with the local authorities, opened a natural-archeological park. In this area, it lies most of the ancient Etruscan city of Velch (today known by its Latin name, Vulci) including the Osteria Necropolis that is the object of this study. Recently, new archaeological excavations were made and the local authorities needed major geological information about the volcanic lithotypes where the Etruscans used to build their necropolis. The aim of this study is to define the geological and geophysical characteristics of the rock lithotypes present in the Vulci park. For this purpose, a geological map of the area (1:10000) has been realized. Moreover, two different geophysical methods were applied: measurements of magnetic susceptibility and electrical resistivity tomography. Magnetic susceptibility analyses clearly identify magnetic contrasts between different lithotypes; the characteristics of the pyroclastic flow that originated the Sorano unit 2 and its vertical facies variations are well recorded by this parameter that along with lithostratigraphic observations provides information about the depositional conditions. Two electrical resistivity tomographies were performed, which show the Sorano unit 2 thickness to be of c. 7 m with resistivity values ranging from 200 to 400 Ω·m. This kind of multidisciplinary approach resulted to be suitable to study this type of archaeological sites, revealing that areas characterized by a relevant thickness and wide areal extension of volcanic lithotypes can be a potential site where Etruscans might have excavated their necropolis.</p>

scholarly journals Disjoint interval bound constraints using the alternating direction method of multipliers (ADMM) for geologically constrained inversion: Application to gravity data

Geophysics ◽  
2020 ◽  
pp. 1-45
Author(s):  
Vitaliy Ogarko ◽  
Jérémie Giraud ◽  
Roland Martin ◽  
Mark Jessell
Keyword(s):  
Gravity Data ◽  
Alternating Direction Method ◽  
Rock Properties ◽  
Model Parameters ◽  
Method Of Multipliers ◽  
Geological Modeling ◽  
Bound Constraints ◽  
Data Inversion ◽  
Alternating Direction ◽  
Geological Information

To reduce uncertainties in reconstructed images, geological information must be introduced in a numerically robust and stable way during the geophysical data inversion procedure. In the context of potential (gravity) data inversion, it is important to bound the physical properties by providing probabilistic information on the number of lithologies and ranges of values of possibly existing related rock properties (densities). For this purpose, we introduce a generalization of bounding constraints for geophysical inversion based on the alternating direction method of multipliers (ADMM). The flexibility of the proposed technique enables us to take into account petrophysical information as well as probabilistic geological modeling, when it is available. The algorithm introduces a priori knowledge in terms of physically acceptable bounds of model parameters based on the nature of the modeled lithofacies in the region under study. Instead of introducing only one interval of geologically acceptable values for each parameter representing a set of rock properties, we define sets of disjoint intervals using the available geological information. Different sets of intervals are tested, such as quasi-discrete (or narrow) intervals as well as wider intervals provided by geological information obtained from probabilistic geological modeling. Narrower intervals can be used as soft constraints encouraging quasi-discrete inversions. The algorithm is first applied to a synthetic 2D case for proof-of-concept validation and then to the 3D inversion of gravity data collected in the Yerrida basin (Western Australia). Numerical convergence tests show the robustness and stability of the bound constraints we apply, which is not always trivial for constrained inversions. This technique can be a more reliable uncertainty reduction method as well as an alternative to other petrophysically or geologically constrained inversions based on more classical “clustering” or Gaussian-mixture approaches.

scholarly journals Phase Change with Density Variation and Cylindrical Symmetry: Application to Selective Laser Melting

2019 ◽  
Vol 3 (3) ◽  
pp. 62 ◽  
Author(s):  
Fyrillas ◽  
Ioannou ◽  
Papadakis ◽  
Rebholz ◽  
Doumanidis
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Phase Change ◽  
Selective Laser Melting ◽  
Unit Length ◽  
Cylindrical Symmetry ◽  
Density Variation ◽  
Laser Melting ◽  
Molten Material ◽  
Melt Pool

In this paper we introduce an analytical approach for predicting the melting radius during powder melting in selective laser melting (SLM) with minimum computation duration. The purpose of this work is to evaluate the suggested analytical expression in determining the melt pool geometry for SLM processes, by considering heat transfer and phase change effects with density variation and cylindrical symmetry. This allows for rendering first findings of the melt pool numerical prediction during SLM using a quasi-real-time calculation, which will contribute significantly in the process design and control, especially when applying novel powders. We consider the heat transfer problem associated with a heat source of power Q' (W/m) per unit length, activated along the span of a semi-infinite fusible material. As soon as the line heat source is activated, melting commences along the line of the heat source and propagates cylindrically outwards. The temperature field is also cylindrically symmetric. At small times (i.e., neglecting gravity and Marangoni effects), when the density of the solid material is less than that of the molten material (i.e., in the case of metallic powders), an annulus is created of which the outer interface separates the molten material from the solid. In this work we include the effect of convection on the melting process, which is shown to be relatively important. We also justify that the assumption of constant but different properties between the two material phases (liquid and solid) does not introduce significant errors in the calculations. A more important result; however, is that, if we assume constant energy input per unit length, there is an optimum power of the heat source that would result to a maximum amount of molten material when the heat source is deactivated. The model described above can be suitably applied in the case of selective laser melting (SLM) when one considers the heat energy transferred to the metallic powder bed during scanning. Using a characteristic time and length for the process, we can model the energy transfer by the laser as a heat source per unit length. The model was applied in a set of five experimental data, and it was demonstrated that it has the potential to quantitatively describe the SLM process.

Temperature, strain rates, and rheology: the key parameters controling strength variations in the Australian lithosphere

2020 ◽  
Author(s):  
Magdala Tesauro ◽  
Mikhail Kaban ◽  
Alexey Petrunin ◽  
Alan Aitken
Keyword(s):  
Heat Flow ◽  
Seismic Tomography ◽  
Seismic Velocity ◽  
Gravity Data ◽  
Geophysical Methods ◽  
The Other ◽  
Crust And Upper Mantle ◽  
Large Variability ◽  
Other Hand ◽  
Australian Plate

&lt;p&gt;The Australian plate is composed of tectonic features showing progression of the age from dominantly Phanerozoic in the east, Proterozoic in the centre, and Archean in the west. These tectonic structures have been investigated in the last three decades using a variety of geophysical methods, but it is still a matter of debates of how temperature and strength are distributed within the lithosphere. We construct a thermal crustal model assuming steady state variations and using surface heat flow data, provided by regional and global database, and heat generation values, calculated from existing empirical relations with seismic velocity variations, which are provided by AusREM seismic tomography model. The lowest crustal temperatures are observed in the eastern part of the WAC and the Officer basin, while Central and South Australia are regions with anomalously elevated heat flow values and temperatures caused by high heat production in the crustal rocks. On the other hand, the mantle temperatures, estimated in a previous study, applying a joint interpretation of the seismic tomography and gravity data, show that the Precambrian West and North Australian Craton (WAC and NAC) are characterized by thick and relatively cold lithosphere that has depleted composition (Mg# &gt; 90). The depletion is stronger in the older WAC than the younger NAC. Substantially hotter and less dense lithosphere is seen fringing the eastern and southeastern margin of the continent. Both crustal and mantle thermal models are used as input for the lithospheric strength calculation. Another input parameter is the crustal rheology, which has been determined based on the seismic velocity distribution, assuming that low (high) velocities reflect more sialic (mafic) compositions and thus weaker (stiffer) rheologies. Furthermore, we use strain rate values obtained from a global mantle flow model constrained by seismic and gravity data. The combination of the values of the different parameters produce a large variability of the rigidity of the plate within the cratonic areas, reflecting the long tectonic history of the Australian plate. The sharp lateral strength variations are coincident with intraplate earthquakes location. The strength variations in the crust and upper mantle is also not uniformly distributed: In the Archean WAC most of the strength is concentrated in the mantle, while the Proterozoic Officer basin shows the largest values of the crustal strength. On the other hand, the younger eastern terranes are uniformly weak, due to the high temperatures.&lt;/p&gt;

scholarly journals Economic analysis of duck eggs incubation using hot spring as heat source

2018 ◽  
Vol 10 (2) ◽  
pp. 38-44 ◽  
Author(s):  
J. Taplah Jr. Anthony ◽  
C. Suministrado Delfin ◽  
Marie C. Amongo Rossana ◽  
O. Paras Jr. Fernando ◽  
C. Elauria Jessie ◽  
...  
Keyword(s):  
Heat Source ◽  
Economic Analysis ◽  
Hot Spring

scholarly journals Utilization of Indonesia’s Hot Spring Sources for Electricity using Kalina Cycle and Organic Rankine Cycle

2018 ◽  
Vol 31 ◽  
pp. 01002 ◽  
Author(s):  
Grano Prabumukti ◽  
Widodo Wahyu Purwanto
Keyword(s):  
Heat Source ◽  
Thermal Efficiency ◽  
Hot Springs ◽  
Hot Spring ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Power Capacity ◽  
Spring Temperature ◽  
Kalina Cycle

Indonesia posses 40% of the world's geothermal energy sources. The existence of hydrothermal sources is usually characterized by their surface manifestations such as hot springs, geysers and fumarole. Hot spring has a potential to be used as a heat source to generate electricity especially in a rural and isolated area. Hot springs can be converted into electricity by binary thermodynamic cycles such as Kalina cycle and ORC. The aim of this study is to obtain the best performances of cycle configuration and the potential power capacity. Simulation is conducted using UNISIM software with working fluid and its operating condition as the decision variables. The simulation result shows that R1234yf and propene with simple ORC as desired working fluid and cycle configuration. It reaches a maximum thermal efficiency up to 9.6% with a specific turbine inlet pressure. Higher temperature heat source will result a higher thermal efficiency‥ Cycle thermal efficiency varies from 4.7% to 9.6% depends on source of hot spring temperature. Power capacity that can be generated using Indonesia’s hot spring is ranged from 2 kWe to 61.2 kWe. The highest capacity located in Kawah Sirung and the least located in Kaendi.

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