Two dimensional (2D) resistivity survey was conducted on a teak field behind the MIPA building of UNSOED, Purwokerto. The purpose of this research was to know the subsurface condition of the teak field, so that can also determine the suitability of the field to teak plant. The survey was conducted using resistivity-meter NANIURA type NRD 22S. The type of configuration was used is Wenner, with a minimum electrode spacing of two meters and maximum of ten meters. The measurement conducted for three tracks, namely LJ1, LJ2 and LJ3 with length of them self are 64 meters, 70 meters, and 40 meters, with relatively flat topography at an altitude of 110 meters above sea level. Data processing was done using RES2DINV 3.57.37 software that the result is a 2D-image of subsurface resistivity. The depth is obtained for each track is 5.37 meters. Interpretation of hydrogeology refers to local geological information. The result of interpretation is digitized using Arc-View GIS 3.3 in order to obtain final result that is hydro-geological images. The result of research show that at the LJ1 and LJ3 contain two layers of rock, there is sandy soil and clayey sand. At the LJ2 track there are three layers, sandy soil, clayey sand, and sand. The resistivity value of sandy soil is 79.4 – 193.0 Ωm, resistivity of clayey sand is 18.9 – 83.4 Ωm and resistivity of sand is 15.7 – 31.8 Ωm. The more downward tendency of resistivity value is more smaller, which indicates more water content. The results of research show that the layers of rock which is found in the land of teak is sandy soil, clayey sand and sand. According to the reference, the entire layer of rock is less than optimal to plant teak. Keywords: 2D-resistivity, land of teak plant, sub surface, Wenner configuration.
The equipment has been designed to measure the dielectric properties of soil samples with lissajous technique in Basic Physics Laboratory, Study Program of Physics, Faculty of Science and Engineering, University of Jenderal Sudirman, Purwokerto. The equipment has been used to measure the dielectric constant of 19 soil samples taken from several locations in area of Purwokerto city and its surrounding, at a frequency of 100 kHz. The measurement has been conducted on soil samples with the variation of soil mass water content. The results obtained indicate, the existence of a correlation between the dielectric constant of soil samples to the soil water mass content (h) which can be expressed with two equations; dielectric permittivity e = 0.3176 h-2.5555 with a correlation coefficient R2 = 0.9538, and dielectric loss equation e= 0.00003 h -5.3336 with a correlation coefficient R2 = 0.9513.
The innovative knowledge for modelling of the wave propagation is solitary waves. The dynamical model of solitary wave represented in Korteweg de Vrise (KdV) equation form. In this modelling assumed that the KdV equation has not perturbation sign, so called Basic Korteweg de Vries (BKdV) equation. This modelling begins from expressing of the BKdV equation into to discrete form as its linear form using implicit scheme for finite difference method. Then, it linear form constructed into matrix form. The solution of matrix form determined using Gauss-Jordan method for resulting of the numerical solution of the BKdV equation. numerical solution was representing on the surface-graphic for the wave envelope as representation of the dynamical non linear in the water. This modelling results indicating that the wave envelope was has distortion of initial amplitude on longstanding of time. It indicate that the fluid energy was has distortion on longstanding of time. Key Word: Soliton, KdV, Numerical, Wave, Envelope
Magnetic survey has been carried out to estimate the subsurface magnetic anomaly model inDarmakradenan Village, Ajibarang District, Banyumas Regency. After the data processing whichincludes some corrections and reductions, then obtained the residual magnetic anomaly data in theresearch area. Then this magnetic anomaly data was modeled use Mag2DC for Windows software,thus obtained four subsurface anomalous objects, which are interpreted as coarse grained sandstones, conglomerates, and andesitic breccias from Tapak Formation (χ = 0.0055 cgs units), lava depositionof Slamet Volcano; with boulder of basaltic-andesite from old Slamet Volcano eruption (χ = 0.0175 cgs units), andesitic sandstone, tuff conglomerate, and marl which insert of sandstone from HalangFormation (χ = 0.0015 cgs units), and limestones from Tapak Formation (χ = 0.0035 cgs units). The research areas have natural resources of limestone that is being cultivated mining now. While thepresence of gold minerals can not be determined, but is expected in the old alluvial deposits of TapakFormation and Halang Formation.Keywords: Magnetic anomaly, subsurface, Darmakradenan Village
Estimation of the subsurface geological structures of Slamet Volcano area, Central Java, has been done by utilizing gravity field anomaly data of image of Geodetic Satellite (Geosat ) and European Remote Sensing-1 (ERS-1) satellite which has been corrected up to free air correction. This research aims to model the 2D profile of the subsurface geological structure which includes some layers of bedrocks, geothermal reservoir, magma chamber, and other geological structures. The procedure of data processing begins with bougeur and topographic corrections. The data obtained, then transformed to horizontal surface, filtered from the local anomalies effects, and corrected from the regional anomaly effect. The results obtained are in the form of residual gravity anomaly data. Modeling is done on the residual gravity anomaly data using 2 Â½-D Talwani method packaged in Grav2DC for Window software. The modeling results show the subsurface geological structure of Slamet Volcano region consists of andesite magma with density value of 2.45 gram/cm3, old lava rock with density value of 2.9 gram/cm3, andesite rock with density of 2.54 gram/cm3, and andesitic â basaltic rock with density of 2.67 gram/cm3. Based on the research area geological information, strongly estimated that the geothermal reservoirs layers are in the andesite rock by filling in it pores or it fissures in the rock. Keywords: gravity field anomaly, modeling, geothermal reservoirs, Slamet Volcano.
Measurement of magnetic data has been done in the area of ââthe gold mining in the village of Cihonje, the district of Gumelar, the regent of Banyumas in May to June 2013. Based on the modeling that has been conducted on the local magnetic anomalies along cross section of AB obtained six models of subsurface rock, while for along cross section of AB obtained five models. Based on the modeling results, rock formations that developed in the research area are Tapak formation, Halang formation, andesite-basaltic, and the alternating formation of the sandstones with some other rocks. The magnetic susceptibility of subsurface rock in the research area are interpreted ranged from 0.0039 to 0.0174 cgs units with the average magnetic susceptibility of rocks is estimated equal to 0.0099 cgs units that interpreted as the alternating formation of sandstone and claystone from Halang formation. The mineralization of gold ore is estimated to occur in almost of all subsurface rocks, but the most dominant mineralization is estimated to occur in the Halang formation especially on the alternating formation of sandstone and claystone. The gold ore mineralization occurs in the form of veins of pyrite, chalcopyrite, galena, and the others, that fill the cracks and the pores of the rocks. Keywords: magnetic anomaly, gold mining, Village of Cihonje
Self Potential research has been done in the area of geothermal prospectsof Slamet Volcano, with locations is at around the hot water sources of PancuranTujuh Baturaden, District of Banyumas, Central Java. Tools used in this study wereporous pot electrodes and digital milivoltmeter that have very high input impedance.Dimension of research area are 24 x 24 square meters, with the number ofmeasurement points are 112 point. The electrode configuration used is the fixedmodel that is by keeping one electrode fixed at the reference point, while the otherelectrode moved at any interval in accordance with the direction of trajectory in theresearch area. According to the results obtained is known that the highest potentialdata obtained is -2.20 mV, the lowest data is -40.83 mV, and then the average data is-16.40 mV. According to the contour map of iso-potential obtained is known that thestudy area is a conductive zone, which probably contains of sulfide minerals in thesubsurface hot fluid. This is indicated by the low value of the measured self potential(its value are negative). According to qualitative and quantitative interpretation, knownthat the flow of subsurface hot fluid in following the change of research areatopography and self potential anomalies. The subsurface hot fluid in research area ispredicted flow from southern to northern.
Identification of geological resources can be done either using surface mapping and cross sectional stratigraphyÂ measurement or geophysical approximation beneath the earth surface. Geomagnetic exploration related to the existing of gold mineralÂ begins with the total magnetic field intensity measurements at 173 locations was scattered in 109.196970 - 109.207580E and 7.448830 -Â 7.454110S. Interpretation from processing of data obtained four anomalous object, which is defined as fine-medium sandstone (Ï=Â 0.0015 cgs units), coarse sandstone and compact (Ï= 0.0035 cgs units), igneous basalt-andesite old Slamet (Ï= 0.0085 cgs units), andÂ the complex bedrock (Ï= 0.0145 cgs units). The presence of gold mineralization in the rock throughout geomagnetic surveys used toÂ identification of subsurface geological which is interpreted from the processing data that indicated the presence of gold in associationÂ with sedimentary (sandstone) is often referred to as sediment-hosted.
Pemodelan sesar di wilayah Kecamatan Banjarmangu Kabupaten Banjarnegara telah dilakukan. Penelitian bertujuan untuk mengetahui model struktur sesar di sekitar Kecamatan Banjarmangu Kabupaten Banjarnegara berdasarkan data anomali gravitasiatau anomali bouguer. Data yang digunakan adalah data sekunderyang diambildari Peta Anomali BouguerLembar Banjarnegara dan Pekalongan. Nilai anomali bouguer yang dihasilkan berkisar -4 â€“ 69 mGal dengan pola kenaikan kontur anomali cenderung berarah timur laut â€“ barat daya. Proses pengolahan data dilakukan dengan mereduksi data anomali bouguer ke bidang datar dan pemisahandata anomali menjadi anomali residual dan anomali regional menggunakan metode pencocokan polinomial. Data anomali residualhasilpemisahandimodelkan menggunakan perangkat lunak Grav2DC for windows. Hasil pemodelanberupa struktur geologibawah permukaan yang diinterpetasi sebagai sesar naik sepanjang 13 kilometer dengan arah barat laut â€“ tenggara.Sesar ini memanjang dari koordinat 109o38Â¢BT dan 7o16Â¢LShingga 109o43Â¢BT dan 7o20Â¢LS. Batuan bawah permukaanhasil pemodelan yang diperoleh di daerah penelitian terdiri atas batulempung dengan densitas 1,63 â€“ 2,60 g/cm3, batupasir dengan densitas 1,61 â€“ 2,76 g/cm3, batupasir gampingan dengan densitas 1,61 â€“ 2,90 g/cm3, dan batugamping dengan densitas 1,93 â€“ 2,90 g/cm3.
Exploration to groundwater sources has been done at Kedungwuluh,District of Kalimanah, Regent of Purbalingga Central Java using GeoelectricResistivity method with Wenner configurations. This research done at around ofagriculture land in Kedungwuluh. The objective of this research is interpret todepth and properties of groundwater aquifer based on resistivity data of Wennerconfigurations. The lenght of measurement trajectory in this research area are300 meters, that outstretched from coordinate of 07Â° 23â² 46.5â³ S and 109Â° 18â²42,9â³ E up to 07Â° 23â² 56â³ S and 109Â° 18â² 42,9â³ E. The results that obtained fromthis research is two dimensionly (2D) resistivity profile of sub surface rocks,which contains of some layers or section of rocks, i.e: sandy claystone (< 53,35ïm), clayey sandstone (53,35 up to 75,35 ïm), smooth sandstone (75,35 up to249,00 ïm), and compacted sandstone and gravel (>249,00 ïm). Based on theresults of the interpretation, estimated that rock section which most dominant asgroundwater aquifer is smooth sandstone, and then clayey sandstone, thensandy claystone. While compacted sandstone and gravel is not estimated asaquifer.