- Home
- Conferences
- Conference Proceedings
- Conferences
EAGE-HAGI 1st Asia Pacific Meeting on Near Surface Geoscience and Engineering
- Conference date: April 9-13, 2018
- Location: Yogyakarta, Indonesia
- Published: 09 April 2018
1 - 50 of 115 results
-
-
Case Studies: Identification of Subsidence Problem Using Electrical Resistivity Imaging
Authors N. Yunus, M.H. Arifin and K.I. Abdul RahimSummaryThe settlement problem can cause a major damage to the building foundation thus could probably causing harm to the surrounding area. Therefore, three locations has been chosen to discuss this matter which located at Batu Pahat, Johor, Shah Alam, Selangor and Sungai Siput, Perak. Electrical Resistivity Imaging (ERI) method has been chosen to measure the resistivity of subsurface materials and identify the causing factor of subsidence at these locations. The instrument used is ABEM Terrameter SAS 4000 System. Resistivity profiles showing the subsurface condition of the study area which indicated various factors that causing the subsidence at these areas. Remediation process must considered several factors including suitability of proposed method including the causing factors, lithology and severity of the damage.
-
-
-
Travel-Time Tomography Imaging around Sinabung Volcano during 2010–2017 Eruption Period
Authors A.T. Sasmi and W. SuryantoSummarySinabung Volcano, which never shown any certain volcanic activities since its last eruption in 16th century, suddenly errupted at August 29, 2010. The disaster has not just stopped. Sinabung eruption repeatedly occurred at 2013, 2014, 2016, and 2017, with unstable change of eruption statuses. This research is aimed to identify relationship between Sinabung Volcano recent erruption activities, with distribution of P-wave anomaly around Sinabung Volcano.
Seismic velocity values are derivative form of travel time value. Some factors which influence a seismic velocity condition are lithology type, rock density distribution, rock porosity, rock depth and pressure condition, also fluids saturation in study area. This research was implemented using earthquake travel time data of January 2010-May 2017 period, from Indonesian agency of Meteorology, Climatology and Geophysics (BMKG) earthquake catalog. Data processing was done by Simulps14 program to create distribution map of Vp anomaly from the targeted area.
The result showed that vertical variety of P-wave velocity beneath Sinabung Volcano indicates relation with partial melting zone and fracture which were formed at the end of 2013. This features led Sinabung into big eruption at January 2014.
-
-
-
The Application of Magnetic Resonance for Formation Pressure Tester and Stimulation Optimization in Produced Carbonate Reservoir
Authors Cahyo Nugroho, Viet Le, Al-Turkey Shaikha and Mohammed Ali Al-IbrahimSummaryA producer well with tight carbonate reservoir was planned for stimulation with objective of production improvement. The strategy for the stimulation was hydraulic fracturing in a fishbone completion. Magnetic resonance and formation pressure tester were used to evaluate fluid content, rock quality and formation pressure of the reservoir. The magnetic resonance had helped to identify the formation pressure tester points and resulted all good test in tight carbonate. The magnetic resonance had delivered remaining oil saturation and rock quality in regards to porosity and permeability. The oil saturation and rock quality were integrated to choose the sidetracking intervals of fishbone completion. The fishbone completion was to be stimulated with hydraulic fracturing to connect the good oil saturation and rock quality intervals, and to enhance permeability of fair rock quality. This application is first use of magnetic resonance in a revisited producer well of tight carbonate reservoir.
-
-
-
Identification of Heat Source and Alteration Zone of Parangwedang Geothermal System using Magnetic Method
More LessSummaryResearch using magnetic method has been done on geothermal area located in Parangtritis, Yogyakarta. This geothermal system is often called Parangwedang geothermal system. This research aims to map alteration zones and predict the existence of heat source in Parangwedang geothermal system. The research was conducted by acquiring magnetic method data on 2x1 km2 area around the manifestation of parangwedang hot water with measuring point in the form of uniform grid with the number of 174 points of measurement and spacing between the points 100 m. The result of the magnetic method is a total magnetic field anomaly map that will be analyzed qualitatively to determine the extent of the alteration zone and the predicted presence of heat source. The alteration zone is mapped to a low magnetic anomaly located in the southwest of the research area. The existence of heat source is suspected to be in a high magnetic anomaly located just below the manifestation of hot water parangwedang.
-
-
-
Evaluating problematic landslide-risked site using hydrogeophysics, isotope and conventional hydrological techniques
SummarySlope failures, landslide and settlement of foundation (subsidence) typically do not occur spontaneously. In this context, the task of predicting the exact failure is difficult, as the point of ultimate failure is dependent on a number of factors ranging from geologic structures of the area to land use change. The first stage in any assessment of a landslide-risked area is the establishment of a reliable conceptual model of the subsurface conditions. Here we present initially results from a study conducted at Bukit Tinggi National Secondary School, Pahang, Malaysia prior to the likely occurrence of landslide activities. Our focus is to evaluate problematic subsurface of a natural landslide-risked using integrated geophysical, isotopic hydrology and conventional hydrological techniques. In this preliminary stage of the study, field screening began with minimally intrusive techniques: electrical resistivity tomography and seismic refraction surveys. The results of geophysical techniques are supported by the isotopic signature which may give a direct insight into the origin and distribution process within the hydrological system. It can be concluded that these techniques complement the conventional hydrological and hydrogeological methods employed in problematic site assessment and their use should be encouraged.
-
-
-
Geotourism Development Planning in Paleobotany Park Merangin
Authors A. F. Bobbybuana, S. Dwiputri, M. I. Pribadi, R. A. Puteri, I. Azizah, A. M. Fath, B. Ansori, A. Sidik and D. SaputraSummaryGeopark Merangin Jambi located in the Jambi Province administratively. The total area of Geopark Merangin Jambi is 20.360 km2. Currently, Geopark Merangin Jambi is in the process of being certified as Global Geopark by GGN-UNESCO. The Paleobotany Park Merangin with whole area of 1.551 km2 is present as a core region and is situated in the southern part of Merangin Regency, typically along and in flood plains of the Merangin and Mengkarang Rivers. The main obstacles found in Paleobotany Park Merangin based on Author’s observation results are poor accessibility to geosite locations and inadequate management. This constraint is due to the lack of attention from the government and the public awareness to preserve geosites even though Geopark Merangin Jambi is currently in the process of being certified as Global Geopark. Therefore it is necessary to plan the development of geotourism in Geopark Merangin Jambi, especially in Paleobotany Park Merangin as a core region of Geopark Merangin so that constraints can be overcome. The aim of this paper is to introduce as well as publication media to increase local income and in addition it can be used by the Government to develop the Paleobotany Park Merangin in the future.
-
-
-
Audiomagnetotelluric Survey to Characterize the Geological Features of Merren Valley Site, Papua, Indonesia
Authors S. Arjuna, A. Pringgoprawiro and A. SyukriSummaryA drilling plan is quite important to minimize errors during drilling. Information on subsurface geological aspects will helpful in providing supporting information for drilling plan. An audiomagnetotelluric (AMT) survey has been successfully characterized the Merren valley site which is located East of Grasberg mine area, Papua, Indonesia. The AMT survey is aiming to characterize the lithological features and delineate the EESS west fault at the depth as part of wells monitoring drilling program. A total of 57 stations were collected by using Zonge equipment system with dipole 50 m, 25 m spacing between stations, and L shaped configuration. The Zonge software used to produces the 2D electrical resistivity profiles. According to the AMT survey results and comparing with known geological condition of study area shows the near surface layer interpreted as glacial till formation that characterized by a moderately resistivity response about hundreds ohm-m. Meanwhile, the deeper layer that has resistivity response about thousands ohm-m indicated as limestone rock. The EESS west fault zone (lower resistivity) indicated more steeply than fault inferred by conceptual model. The resistivity inversion model appears agree with the geological condition of Merren valley site that can be used for making decision in drilling plan program.
-
-
-
Damage Zone Map Due to Earthquake on May, 27th 2006 in the Area of the Opak River, Yogyakarta Based on MMI Scale
Authors P. Nurhayati, A.S. Banuzaki, B.S. Simorangkir, I. Ilmawan and D.P.E. PutraSummaryJava island has been known to be frequently affected by earthquake. On the other side, the management of earthquake disaster mitigation is still lack of disasters anticipation and mitigation plan. It can be proven by the absence of detail damage-zonation maps of earthquake. The damage-zonation maps of earthquake are needed to assess the impact of future earthquake. Based on the 5.9 richter scale Yogyakarta earthquake on May 27, 2006, the worst affected region was around the Opak River. Therefore, the damage zonation map of earthquake in Opak River is absolutely needed to mitigate the future earthquake cases. The investigation was conducted by interviewing the earthquake witnesses scaterred in 82 locations along Opak River. The results of interview were classified based on MMI (modified mercalli intensity). By apply spatial analysis in GIS, the MMI data were interpolation and extrapolation to damage-zonation map of MMI. Reveal the result the biggest MMI classes was obtained along the Opak River and controlled by fault continuity, earthquake magnitude, distance from epicentrum, litology thickness and litology type.
-
-
-
Two-dimensional Magnetotelluric Modeling Based on Bi-tree Mesh
Authors M. Li, Z.Y. Zhang, M. Xin and S.P. XieSummaryIn order to improve FEM forward modeling efficiency and precision of the 2D magnetotelluric problem, this paper focuses on calculating the response of a two dimensional MT model considering the conductivity and permeability variations simultaneously. These secondary fields method used to solve the secondary variations problems parallel to strike like Wannamaker. A model discrete method based on the bi-tree structure was developed and applied.
-
-
-
Geothermal Control System with Estimated Distribution of Resistivity Value Using AMT Method in Ungaran Area
Authors A. Gilang, A.T. Yuliwardana and A.I. AssidhiqieSummaryGeothermal prospect area of Mount Ungaran is located approximately 30 km southwest of the capital of Central Java, Semarang. The area is physiographically located in the North Serayu Mountains formed by the lifting of the Miocene. This mountain was active between the late Pliocene and the Late Pleistocene. In the area, there is a geothermal prospect located on the southern slope of Mount Ungaran, namely in Gedongsongo area.
Several geothermal manifestations around Mount Ungaran include: fumarole in Gedongsongo area, hot springs in Banaran, Diwak, Kaliulo and Nglimut areas, and altered rocks are found in Gedongsongo and Kendalisodo. From existing research, a geothermal prospect in this area is dominated by water, which is structurally controlled by Ungaran caldera structure. From interpretation AMT, the heat source is thought to be a diorite intrusion with range value resistivity are 2.8–4.0 ohm.m. Cracked volcanic rocks of Lower and Tertiary Quarterly are thought to function as reservoir rocks with range value resistivity are 1.5–1.4 ohm.m. The impermeable upper quartile volcanic rocks are thought to function as cap rocks with range value resistivity are 2.8–4.0 ohm.m. Based on geothermometry on fumarole found in Gedongsongo area, reservoir temperature is estimated to reach 230°C.
-
-
-
Geology and Geophysisc to Discover Cu-Zn Mineralization in Purwohardjo Area, Wonogiri Regency, Central Java
Authors V. P. Harefa, R. A. Hidayah, B. B. Prabowo, D. Aminulloh, R. A. M. Yudha and B. D. DiliantoSummaryThe research is located in Central Java Province, Wonogiri Regency, Karangtengah-Purwohardjo Area. The lithology unit in the research area consists of volcanic breccia units, which are intruded sequentially by the pyroxene andesite, and the dacite. The geological structure of the shear and fracture faults participates in controlling the mineralization in the research area. Based on interconnected relationships in the field, the dacite is interpreted as a mineralization-bearing intrusion. Hydrothermal alteration includes argillic and propylitic alteration. The argillic alteration zones are characterized by the presence of sericite minerals, chlorite and clay minerals, which are generally intensively formed on pyroxene andesite and dacite. The propylitic alteration zones are characterized by the presence of chlorite, epidote and calcite minerals, which are commonly found in volcanic and partly andesitic breccias. Hydothermal alteration is strongly associated with ore mineralization. The copper ore sulfide minerals are chalcopyrite, bornite with a bit of kalkosit and kovelit.
In Induced Polarization profiles the Trend value of high chargeability appears to be related to the presence of metal sulphide minerals in andesite and dacite rocks. Based on the characteristics of alteration and mineralization and from Geophysiscs interpretation, the research area is included in High Sulfidation Epithermal related to Porphiry type.
-
-
-
Application of the bilateral filter to improve derivative based lineaments enhancement approaches
Authors J Wang and X. H. MengSummaryIn the work discussed in this paper, we have applied the bilateral filter to improve the derivative based lineaments enhancement method of gravity and magnetic data. The method was tested using the gravity responses of a combined density model. A comprehensive comparisons indicated that the bilateral filter can effectively smooth the original field data without disturbing the sharpness edges. Filtered data obtained from the bilateral filter can be further used for edge detection stably without losing of useful boundary information.
-
-
-
Lithology and Petrophysic Variations of Carbonate Reservoir Using Rock Typing: Analogue Study in Ponjong, Yogyakarta
Authors I. Ramadhan, A. R. Perdana, P. Herianto and R. HidayatSummaryResearch area shows 3 distinct rock types, RT 1, RT 2, and RT 3 (lacks of data). RT 1 has the highest permeability, compared to RT 2, and RT 3 (lowest). The permeability is very dependent on pores, which has strong relations to diagenetic environment.
Diagenetic processes have implications on pores and cement forming. Cement formed by diagenetic process are bladed isopachous (calcite), formed in fresh water phreatic environment and fibrous isopachous (aragonite), formed in marine phreatic environment. Pore formed by dissolution shows vadose zone
-
-
-
Geology and Hydrothermal Alteration of Cibeber Prospect, Lebak, Banten: a preliminary study of Au-Ag-base metal sulfide deposit and implication to exploration
Authors C. D. P. Dana, A. Idrus, S. D. Masti, F. Yuniardi and I. A. MeakSummaryThe research area is located in Neglasari, Cibeber, Lebak, Banten. As we know that western Java has a big potential in mineral deposits especially epithermal deposits and one of them was found in this studied area. This study aims to understand the geological and hydrothermal alteration as well as the mineralization characteristic in studied area. Surface geological mapping is used to know the geological condition including lithologies and structural geology also hydrothermal alteration distribution. Five representative ore vein samples were analyzed using FA-AAS method to determine the grade of precious and base metal contents. The lithologies found in this area can be divided into 3 unit stratigraphically that is sandstone unit, tuff breccia unit and andesitic lava unit while the structural geology are strike slip fault, normal fault and some joints. There are 4 alteration zone that is silification zone, clay-silica zone, clay zone and chlorite-epidote zone. The mineralization mostly found as hydrothermal veins which can be divided into two type that is precious metal bearing vein or usually called as low sulfidation type and base metal bearing vein or usually called as intermediate sulfidation.
-
-
-
CSAMT investigation for geological structures in a HLRW preselected site
More LessSummaryThis paper discusses the use of Controlled Source Audio-frequency Magnetotelluric method (CSAMT) in geological structure exploration at an area preselected for high level radioactive waste (HLRW) in northwest China. The survey objective is to evaluate the rock mass quality and find the weak geological structures which will cause damage to the safety and stability of underground repository. We conducted a dense CSAMT survey, combined with borehole information to delineate the local weak geological structures. The study was conducted in NW China in 2014. The comparison between the interpreted results and geologic information shows that both are in agreement. The preliminary results offer detailed information about the electrical structures of Nuorigong rock mass from the surface to 1400 m deep, so the interrelationship between the target rock mass and its surroundings were analyzed to show their shapes. In conclusion, CSAMT results are helpful in exploring the subsurface for geological structures and competent rock mass. It can also provide the reliable geophysical evidence and scientific reference for complete and consistent evaluation of the deep geological structures, and aid in comprehensive assessment of preselected sites for HLRW disposal, such as further study in the design and construction of an underground man-made repository.
-
-
-
Site investigation using resistivity survey to investigate possible slime deposit in ex- tin mining area
Authors H. Hussin, M.H. Ariffin and T.A. JamaluddinSummaryResistivity is a well-known method to detect rock resistance value in the subsurface. Its ability to penetrate deep into rock mass have been utilized in various field. In this study, resistivity tomography survey was conducted to identify the present of slime layer in ex-tin mining area which conducted at Kampar, Perak, Malaysia. Slime was a residual material mostly comprise sandy and clayey material. Slime was consider as weak material and can cause problems especially ground settlement. A total of five resistivity survey lines was carried out to cover entire proposed area ( Figure 1 ). Geologically, the study area is underlain by sedimentary and metamorphic rocks which is part of Kinta Formation. Resistivity interpretation shown four different anomalies which are soft layer, compact layer (soil), slime and rock boulder. The present of slime material is deposited 25m below surface.
-
-
-
Geomagnetic Investigation to Delineate Heat Source of Geothermal Potential in Jambi Sub-Basin
Authors A. F. Bobbybuana, F. Randitama and V. AfrionalSummaryPandan Sejahtera Village, Geragai, East Tanjung Jabung, Jambi, is an object study area to make observations, because the discovery of geothermal manifestations in the form of hot springs with a temperature of about 60 degrees Celcius. The study area is located in back-arc basin which is far away from subduction zone and active volcanoes. In geothermal exploration, Geomagnetic Method used to identify the type of rock that is the source of heat. Interpretation of geomagnetic data is done by using Reduce to Pole and Upward Continuation as filters. In order to calculate those filters, Fast Fourier Transform (FFT) was applied to the geomagnetic data by using Oasis Montaj software. Based on the Upward Continuation filter results the Author interpret that distribution of shallow and deep anomalous zone are respectively associated with residual and regional anomaly magnetic. Deep anomaly in the East - Northeast direction is interpreted to be associated with a heat source because it has a low magnetic anomaly value owned by demagnetized rocks due to high temperatures.
-
-
-
Determination of Peak Ground Velocity Observation as Geohazards Parameter in North Sulawesi
Authors R. Priadi, D.A. Pratama and R.B. KurniawanSummaryNorth Sulawesi’s activities are mostly done by triple junction between Eurasian, Philippine and Pacific plates causing seismic activity in the north Sulawesi region. In addition to PGA data there is also one parameter that can be used to characterize the ground response during a earthquake that is PGV (peak ground velocity). PGV is the most frequent value in an area within a given time period due to an earthquake. The result of PGV observation value is obtained if the largest PGV value is 0.25667215 cm/s at the earthquake event of Northern Molucca Sea M 4.8 dated 19 November 2016. Then for the smallest PGV value of 0.000187953 cm/s at event Molusca sea M 4.8 dated 5 May 2016 which recorded maximum at north-south component at TMSI station. The average PGV observation value in North Sulawesi is 0.056756952 cm/s. Areas with large observational PGV values are Bitung, Bolaang Uki, and Kotamobagu districts. PGV values are only good for accurately representing intensity and state of the station for earthquake magnitude below M 6.0. For earthquakes with magnitude M 6.0 or greater it is recommended to keep using PGA to represent ground shaking when an earthquake happend.
-
-
-
2-D time-domain waveform inversion using Gauss-Newton methodology in elastic media, case study: complex marmousi2 model
Authors B.I. Hardi and T.A. SannySummaryFull-Waveform Inversion (FWI) can be defined as an iterative fitting data procedure for obtaining physical properties of the Earth based on the full wave-field data simulation. Hence, FWI is widely known as a comprehensive way to solve the complex structure below the earth surface, it performed a high-resolution image, and very powerful when it combined with the good prior model.
In this research, we especially focusing on how we worked with the 2-D Full-Waveform Inversion (FWI) using Gauss-Newton approach in elastic media. The steps included the forward modeling problem based on the finite-difference and staggered grid scheme that bounded by free-surface boundary condition (on the top of model) and Perfectly Matched Layer (PML) for the rest, also, we applied the Gauss-Newton inversion that exploit the approximate-Hessian into this methodology. For the result, we tested the inversion modeling in simple layer cake model and complex marmousi2 model, both of those models are located in the shallow area.
-
-
-
Comparison Analysis Of Subsurfaces Survey Between Geophysics Method (Geoelectric/Ert) And Geotechnical Method (Standard Penetration Test (Spt) At Kaima Overpass Manado-Bitung Toll Road
Authors Abdurrahman Wafi, Panganggit Sasmito, Mohammad Arief Rizki and Arief RahmanSummaryManado-Bitung Toll Road is one of priority projects announced by Indonesia President, Joko Widodo, to speed up economic growth in North Sulawesi Province. Kaima Overpass is one of many overpass which will be built to provide crossing between Manado Bitung toll road and local roads around it. Geo-electric method or known as Electrical Resistivity Tomography is used to get subsurface data and groundwater, while geotechnical method is used to get data about mechanical properties of subsurface material. The purpose of this research is to know the structure subsurface, estimated volume of hard rocks and soft rocks at Kaima overpass location. Kaima overpass location is dominated by medium rocks and hard rocks from Geo-electric data with value greater than 500 Ohmmeter and Standard Penetration Test N-SPT value greater than 15. The subsurface material structure consists of Andesite and Gravel Alluvium, which come from sediment / lava sediment from Mount Klabat.
-
-
-
Determination of Slip Surface area using Geoelectric, MASW, and Soil Mechanics Data in Cimuncang Village, West Java
Authors R.C. Wibowo, B.S. Mulyatno, M. Romosi and A. ZaenudinSummaryThe research of soil movement has been conducted using resistivity method, MASW, and soil mechanical data in Cimuncang, Malausma, Majalengka. The research has done in order to know resistivity distribution value and shear wave velocity VS30, to determine and analyzing rock layers pattern, slip area depth through 2D and 3D modelling result, and analyzing slope Safety Factor (SF) based on soil mechanical laboratory testing. The estimation of resistivity value is done by applying resistivity modelling, the value is vary from 6–200 Ωm which the depth of slip area is 5–7 m. The estimation of shear wave velocity value is done by applying MASW modelling, the value is vary from 40–500 m/s which depth of slip area is about 5 m. The layer that used as slip area based on resistivity modelling is contact between clay (<25 Ωm) and tuff (25–75 Ωm), and based on MASW modelling that considered as slip area is between soft soil layer (VS <183 m/s) and stiff soil layer (VS 183–366 m/s). Based on Geoslope modelling gained slope Safety Factor (SF) is valued 1,26 in southeast that means the slope is relatively stable and in northwest is valued 0,98 that means the slope is unstable area.
-
-
-
Preliminary 1D PS modelling to evaluation oil generation in Wichian Buri sub-basin
Authors C. Chaiyasart and P.H. GiaoSummaryThe Wichian Buri sub-basin of Phetchabun basin, Thailand is reported the significant recoverable hydrocarbon from fractured igneous rock reservoirs but until now no detailed research has been done to estimate the hydrocarbon generation and intrusion effect to maturation. In this study, an integrated approach was proposed and applied both petroleum system modelling (PSM) and hydrocarbon generation to evaluate potential source rock of Wichian Buri unit IV with intrusion effect. The study was conducted base on the data from public domain of petroleum industry in Thailand, including vertical well sections, well logs, regional geological sections, base maps, and geochemical data. The results of petroleum system modelling (PSM) indicated that potential source rock in Unit IV was maturation and generate HC with the effect of igneous intrusion. The Ro of the source rock is 0.62% and hydrogen index of the source rock is 222 mgHC/gTOC. Hydrocarbon generation was found in the late Miocene basalt tertiary and Permo-Triassic Nam Duk formation. Finally, the hydrocarbon generation estimated 1,392.4 - 2,489.7 MMSTB of Wichian Buri unit IV and results of this study concluded that the igneous intrusion effect to immaturities source rock to generate hydrocarbon.
-
-
-
a-Value and b-Value as Basic Calculation Seismicity Index, Repeated Period, and Vulnerability of Earthquakes
Authors A. Arimuko, F. Yoan, S. Rohadi and K. H. C. WulurSummarya-Value and b-Value can be used to basic calculation to get seismicity index, repeated period, and vulnerability of earthquakes in a region. Yogyakarta is a region of Indonesia that often earthquakes are happened, caused by an active fault it has, Opak fault. And also because it is flanked by Java Megathrust and an active volcano. Earthquake phenomenon is very detrimental to life and many casualties if there is no preparedness to deal with it. This research aims to get the calculation results from seismicity index, repeated period, and vulnerability of earthquakes to indicate areas prone of earthquakes in Yogyakarta. The method used is a matrix inverse calculation, Gutenberg-Richter’s (1956) least square equation, to obtain a-value and b-value. This research uses USGS and BMKG earthquake catalog data and classifies it based on the region of Yogyakarta in geodetic coordinates ie 7.493°-11.523°S and 109.841°-110.940°E. The results of this research is got a-value and b-value calculations in Yogyakarta are found a = 4.0866 and b = 0.6528. And from the calculation results obtained that the seismicity index, repeated period, and earthquake vulnerability that occurs is Mw ≥ 5 in Yogyakarta.
-
-
-
Integrating Geophysics, Geology, and Geochemistry Methods for Shallow Biogenic Gas Exploration in Indonesia
Authors Z. Firdaus, R. Muammar and D. RalanarkoSummaryShallow biogenic gas has long known as a drilling hazard in petroleum industry which responsible for several blowouts in the past time. Despite its infamous name in the industry, biogenic gas usually composed of more than 95% methane and it contains considerable amount of global reserve to be produced in a relatively shallow area. In order to turn biogenic gas into a production horizon, different treatments are needed. This research took place in Bentu PSC, Talangjimar Field, and Tunu Field which are distributed in Central Sumatra Basin, South Sumatra Basin, and Kutai Basin respectively. By integrating AVO analysis (geophysics), burial history and geothermal gradient (geology), as well as carbon isotope and gas composition (geochemistry), one can easily detect the presence of biogenic gas in the subsurface area along with its origin and quality. Our investigation suggested that by combining the three geosciences elements, the chance of exploration success may increase significantly, leading to the addition of biogenic gas reserve to be produced in the future.
-
-
-
The Influence of Focal Mechanism to the Tsunami Wave Height of the Simeulue Aceh Earthquake on April 11, 2012
Authors U.I. Nurdiana, F. Purnamasari and A. NurokhimSummaryEarthquake in Simeulue Aceh happened on April 11, 2012, at 08:39:31 GMT with latitude coordinates 2.35° and longitude 92.82° with magnitude 8.6 Mw. This earthquake occurred at a depth of 45.6 km. Because of this earthquake, the tsunami was recorded in several places. Meanwhile, a small tsunami reportedly hit the island of Simeulue that dragged objects to the coast and created 3 meters height waves in the Gulf of Sibigo, West Simeulue. The April 11, 2012 Simeulue Aceh earthquake was the largest earthquake caused by a strike-slip fault. This earthquake was categorized as an outer-rise quake because it was located outside the subduction zone. The April 11, 2012 Simeulue Aceh earthquake was dominated by horizontal (strike-slip) component, where the horizontal component was dominant, so it did not generate the large tsunami waves. The tsunami propagation models also different between the tsunami model without the focal mechanism and with the focal mechanism (we used strike 20 and 289). From 2 data station, Sabang and Nancowry validation result, then compared the observation result with IOC data, so we know that the height of tsunami was influenced by focal mechanism, in this case, the strike 289 is the nearly compatible with IOC data.
-
-
-
Volumetric Calculation Based On Comparative Resistivity Imaging Analysis Between Marquadt And Occam Inversion: An Andesite Quarry Case Study
Authors Aditya Aries Furkhan, Agra Adipta and Wrego Seno GiamboroSummaryVolumetric determining in mining prospect encounters certain biases. Resistivity imaging was comprehended to determine the resistivity distribution of the andesite body. Inversion is used to characterize a subsurface properties upon the geological condition. Inversion data are transformed into model parameters which could explain the possible subsurface properties that may cause the data be obtained based on the acceptable forward formulation ( Martakusumah and Srigutomo, 2015 ). Marquadt and Occam inversion are non-linear inversions with a linear approximation. Both of inversions are used on the resistivity data resulting a comparative resistivity model. The result from Marquadt inversion suites more with the geological condition, in contrary with Occam inversion. Andesite body identified as a high resistivity value ranging 400 – 2000 Ω.m. Marquadt inversion portray intrusion shaped andesite with a volumetric reaching 9,987 x 106 m3.
-
-
-
Surface deformation monitoring of Mt. Agung by Sentinel-1 DInSAR
SummaryPhreatic eruption occurred on November 21, 2017 on Mount Agung with the ash cloud reaching the height more than 3,800 meters. This was followed by multiple magmatic eruptions occurred since November 25 to 27. Volcanic activity has been weakened after November 29, but it is still continuing.
In this study, recent status of the surface deformation of Mt. Agung, detected by DInSAR using Sentinel-1 satellite data, is reported. Preliminary results indicate that no deformation occurs before the phreatic eruption, but after the eruption a swell on northern slope may occur.
-
-
-
3D joint inversion of gravity and magnetic data based on structure similarity of node physical property model
Authors S. L. Li, N. P. Wang, X. H. Meng and J. WangSummaryThe node physical property model with good sparseness is the difference form of its corresponding block physical property model. It can not only eliminate computational redundancy and improve the efficiency of forward computation, but also can effectively recover simple geology models. The developed gravity-magnetic simultaneous inversion method introduces the structure similarity constraint between two node physical property models to make the inversion results have the characteristics of structural consistency. The Cauchy norm constraint can be used to get a sparse solution. Within the conventional inversion framework, this strategy does not need to apply nonlinear functions such as physical property transformation function to overcome the problem of nonlinear enhancement, and the inversion results are not affected by the initial value. The model tests show that the inversion method can effectively recover simple geology models. The boundary of the recovered anomalies is clear and the location is close to the real position. The block physical property values of the recovered anomalies are also closer to their true values. Compared with the inversion using only one geophysical method data, the joint inversion improves the vertical resolution of anomalies to a certain extent, and inhibits the generation of partial interference anomalies.
-
-
-
Seismic Wave Modeling of Numerical Dispersion using Cross-rhombus Stencil
Authors A.D. Sonya and T.A. SannySummaryFinite difference is a popular method that used for seismic wave modelling, but it still suffer from numerical dispersion problem. Stencil is one of finite difference aspect that affect its accuracy, including the dispersion. Cross-rhombus stencil is a new stencil scheme which combine the standard stencil and a diamond-shaped stencil called rhombus stencil. It is proved that it can reduce numerical dispersion in finite difference method and increasing its efficiency. Since it is new scheme, cross-rhombus stencil has a lot of things to be studied. We described basic theory of this stencil scheme and its application to a simple seismic modeling simulation.
-
-
-
Surveying the layers of pavement using ground-penetrating radar
Authors K. Onishi, H. Kisanuki, T. Ogahara and T. InazakiSummaryMulti-channel GPR with ground coupled antennas can acquire underground records with little amount of multiple reflections. We use multi-channel GPR equipment, which can scan at high speed on a paved road, to acquire underground survey records at a test road which has many sections composed of different type of materials and depths. The records clearly indicate horizontal boundaries of road construction without processing of background removal. We acquired zero-offset profiles applying normal moveout (NMO) correction for GPR records. NMO correction is useful to detect the shallow boundary below asphalt concreate mixture. GPR with bow-tie antenna of ground coupled type, which can scan on paved road at high speed has high potential to monitor the condition of road construction.
-
-
-
Large 3D resistivity and IP measurement of the Séchilienne landslide using the FullWaver system
Authors C. Truffert, P. Nevers, M. Lajaunie, J.P. Malet, C. Bertrand, J. Gance and O. LeiteSummaryLa Séchilienne is a hudge deep seated landslide located in the French Alps. Authors will present a full 3D Electrical Resistivity Tomography (ERT) performed with the FullWaver(c) system designed by Iris Instruments. This distributed, autonomous and cable free solution allows to restitute a 3D distribution of resistivities useful for a better understanding of the geometry and the processes of the landslide.
-
-
-
Paper Title for Landslide Identifications Based on Geology and Geoelectricity Mapping Analysis, Study Area: Road Province Pacitan-Ponorogo, East Java, Indonesia.
Authors L. R. Daryono, A. Hendratno, M. Nukman and E. HartantyoSummaryUnderstanding of landslide mechanism was imperative to appropriate the mitigation geotechnical methods. Engineering geological investigation and geoelectrical dipole-dipole resistivity analysis were carried out in the studied area to elucidate the mechanism of the landslide. The engineering geological investigation consists of local topographical mapping. The geoelectrical dipole-dipole resistivity analysis assessment of the problems affected landslide was conducted by a sub-surface imagine using resistivity contrast. The results presented in this paper successfully detect fractures at various depths and their position with the resistivity low contrasts as claystone is among the high-resistivity zones (volcanic rock). Low resistivity zone has a pattern with a slope of ∼45 degrees to the East and acted as field shear-surface the movement of soil in landscape survey. Interpretation of resolution lithology and shear-surface fields ranging between 25 – 30 m.
-
-
-
Integrated Remote Sensing and Geological Mapping to Identify Landslide Prone Zone in Loano, Purworejo, Central Java
Authors I. D. Puta, A. Hirawan, R. Abbas and A. D. TitisariSummaryLandslide is one geological disaster with a high risk that often occurs in Central Java Province, including in the Loano Area, Purworejo District. .Today there are many people in Loano who dwell in areas prone to landslide. However, it is necessary to conduct integrative research activities as a form of disaster mitigation to reduce the landslide risk. Research conducted in the form of remote sensing, geological mapping and GIS (Geographic Information System) analysis. Remote sensing observation shows that the factors control the Landslide are the presence of non vegetation in the southeast and west side of the areas, the slope (<15O), less crystalline rocks, geological structure, and hydrothermal alteration minerals.The lithology is composed of 4 rock units: basaltic andesite, andesite, tuffaceous sandstone and andesite breccia. The alteration zone lies in the unit of andesite lava lithology. The various clay minerals minerals in the form of illite, smectite, and kaolinite are the result of hydrothermal alteration which can be classified as an argillic type. There are 10 points of landslide prone zone. The zone is characterized by a slope above 15o and a high alteration level. Highfall rate of rainfall (131 – 241mm/month) in Kulonprogo area also believed control the landslide.
-
-
-
Identification of Landslide Vulnerability Using Seismic Refraction and MASW: Study Case in Kulonprogo, Indonesia
Authors H. S. Mahandani, K. S. Brotopuspito and A. AnggrainiSummaryResearch on landslides has been done in Purwosari Village, Girimulyo Sub-district, Kulonprogo Regency with Seismic Refraction and MASW’s methods. The study consists of 20 Seismic lines to determine the level of landslide vulnerability in the researh area. Vp and Vs values obtained are then used for calculating the elastic properties of rocks in the weathered layers. Result of the analysis shows that the most vulnerable area of landslides is in District of Gedong in Purwosari Village which is located in North-West of the research area. This area has a low Vp, Vs, density, Shear and Young’s Moduli with high Poisson’s ratio indicates that the area is water saturated. Water saturated slope will have lower frictional force that makes the weathered layer prone to landslide.
-
-
-
Estimation of Aquifer Properties Using Surface Based Electrical Resistivity Tomography
Authors T. Fadilah, L. Gross and R. SchaaSummaryAquifer characterization such as hydraulic conductivity (K) is necessary due to groundwater sustainability for agriculture industry. The current method for calculating K is to conduct a pumping test or a permeability test. This study is trying to find an alternative method to obtain a K value by determining the correlation between water and aquifer resistivity which is conducted in the laboratory and field scale. The aquifer resistivity is gathered from Electrical Resistivity Tomography (ERT) and the water resistivity from direct measurement. The correlation can perform the Kozeny–Carman equation, which is modified from Archie and Waxman–Smits formulas, to estimate the hydraulic conductivity. The hydraulic conductivity estimation is compared with the hydraulic conductivity value from the permeability and pumping test solutions. The measurement result showed 12.63 m/day, which was similar to the permeability test with 10.3 m/day. However, the field result revealed 14.07 m/day, while the pumping test indicated 24.5 m/day. An analysis has been conducted with the fact that geological condition, grain size, and water resistivity have a significant contribution to the result. Nevertheless, the outcome of the ERT profile can be an alternative method to get an estimation of K that is more efficient, yet not offensive.
-
-
-
Resistivity Method with Werner-Schlumberger Configuration to Analysis Seawater Intrusion at Teluk Betung Area, Lampung
Authors Taufiq, H.D. Mega and A. ZaenudinSummaryTeluk Betung area is an area in the southern coastal of Bandar Lampung city directly adjacent to the sea. Based on a survey of residents wells in the area, indicating that the groundwater in this area has been contaminated by seawater (brackish) so it is not suitable for consumption. This occurs because of the increased need for fresh water in proportion to increase of population in the region resulting in ground water exploitation continues to increase every years. The reduced water content in the soil may result in the entry of the aquifer layer of seawater into the aquifer zone and contaminate ground water, this condition is often referred to as seawater intrusion. To mapping the pollution zone caused by the seawater intrusion we used resistivity method.
-
-
-
The Groundwater Survey by using Resistivity Method and its Application in the Republic of Rwanda
Authors K. Nakamura, T. Aizawa and S. MatsudaSummaryThis paper presents result of the groundwater survey by using resistivity method and its application especially in the developing countries based on the lessons learnt through the feasibility study of irrigation facility rehabilitation project in Republic of Rwanda in eastern Africa.
As a result of the study, the water catchment structure was examined by resistivity survey, and availability of water resource was also confirmed. In addition, it was confirmed that the interpretation of the resistivity survey results for the water catchment structure in the laterite soil of this country is appropriate. This suggests that there is sufficient possibility of project cost reduction due to early implementation of resistivity survey. In the future, it is considered that similar interpretations can be made in the case of constructing an alternative water facility in the vicinity of a place already having a spring as in this time.
-
-
-
Search for and investigation of volcanoes with gravity surveys
By J. MrlinaSummaryGeophysical methods, mainly gravimetry and magnetometry, can serve as suitable tools for location of unknown hidden volcanic structures that are not expressed by any typical topographic features. These may be e.g. diatremes and maars with eroded scoria cones or rims of tuff/tephra material, as well as lava flows.
Gravity survey may reveal significant negative anomalies due to low density of the filling of volcanic vents, or positive anomalies over the bodies of compact lava accumulation. Magnetometry would rather show positive anomalies related to most of the volcanic structures due to high content of magnetic minerals in the volcanic rocks (except acid trachytes/phonolites/rhyolites). Geophysical surveys should therefore form part of any investigation of volcanic fields where some unknown volcanoes may still be expected.
Gravity monitoring can reveal hidden mass and fluids movement in a volcano interior, and can therefore contribute to the hazard control at regions with active volcanoes.
-
-
-
Seismic Lahar Characteristics of Merapi Volcano Post 2010 Eruption
Authors Sulistiyani, IGM. A. Nandaka and NurudinSummaryMerapi 2010 eruption ejected at least 130 million m3 volcanic material, mostly enter to Gendol River. More than 100 lahar events were generated around Merapi. Lahar at Merapi triggered by the rain intensity occurred at the summit. BPPTKG built the lahar flow monitoring station in order to mitigate the lahar disaster. The intention was to give early warning to the society. Lahar flows monitored using non-contact detection instrumentations installed near the rivers. These devices were geophones and IP-based camera.
This paper will present the seismic lahar characteristics recorded at Kali Gendol station. Events recorded on February 21, 28, April 23, 24 and also May 1, 2011, has been analyzed to know the characteristics. Most of the data had saturated amplitude due to the big magnitude lahar caused by the blocky materials. Seismic signal shows that the flow can be differentiated into single-pulse and multi-pulse events. Dominant frequency before the arriving of the lahar was fluctuating because of the human activity, traffic, etc., while the body of the lahar was 8–18 Hz. Maximum amplitude ranged between 1x104 – 1.9x104 Count (saturated). By knowing these lahar characteristics, amplitude and frequency result can also be used to refining the lahar early warning system.
-
-
-
Hypocenters Relocation Using Double Difference Method Around Mount Agung, Bali
Authors E. Ulfiana and R. M. SipayungSummaryAfter a long sleep for 54 years, now we are surprised by the presence of seismic activities of Mount Agung that has recorded since September 2017. We can’t prevent the eruption, however we can observe magma movement in the body of volcanos. Hypocenters distribution is an important information that can be used to reveal the magma movement in the body of volcano. For a more accurate hypocenter, we did relocation of earthquake hypocenter that has occured in Mount Agung area, periode September–November 2017 (Catalog data from BMKG). We used Double Difference method that compute in HypoDD program. We success relocated 331 from 415 events that occured since September-November 2017 in Mount Agung area. The hypocenter distribution looks more accurate and earthquakes are located under Mount Agung with range depths 3–42 km. The dominant hypocenter distribution lies to the southwest of Mount Agung, ie toward the middle between Mount Agung and Mount Batur. Magma is going move toward the surface or in brittle zones of Mount Agung. The small eruption has occured in Mount Agung, so we expected a higher probabilty for a large eruption can be occure following these small eruptions.
-
-
-
Spectra analysis for source dynamic identification of deep volcano tectonic underneath mounth Sinabung, North Sumatera
Authors K. Brotopuspito, T. Kusmita and H. TriastutySummarySpectra frequency of VT indicates the effective stress of volcanic activity. Spectra frequency of VT indicates the effective stress of volcanic activity. These spectra parameters could be applied to determine source and the dynamics of the source of the VT earthquake. This study analyzed the spectra VTA earthquake in the Sinabung volcano between July and November 2013, by applying the FFT algorithm based on the Brune model. Analysis show that the corner frequency of VTA earthquakes of Sinabung volcano were dominated by frequency of 12 – 13 Hz. Hypocenter positions were at a depth of 2 km - 20 km from the summit. Epicenter positions were spread towards the Northwest from the summit, i.e to the Lake Kawar direction. Most of the VTA source mechanisms are strike slip and oblique, and small portion of normal faults and reverse faults. Energy accumulation before the eruption was occurred from July to August and after eruptions in October. On this October accompanied by the formation of a new dome and followed by a magmatic eruption in November. Fractures that triggered the eruption was happened on September 12nd, 2013 and ended on September 22nd.
-
-
-
Identification of Distribution and Calculation of Manganese Reserves from VLF and IP Method in Pengasih, Yogyakarta
More LessSummaryResearch about manganese reserves has been done in the Karangsari Village, Pengasih District, Kulonprogo Special Region of Yogyakarta. Explorations and exploitation of manganese has been done by local community using traditional method. This research aims to determine the condition of subsurface, manganese distribution, and the amount of manganese reserve in research area. The method used is VLF method and IP method. The line of VLF measurement is 6 line with 300 m length. IP line using dipole-dipole configuration has 5 lines and 300 m length, spacing between electrode 20 m and number n 8. The aquisition using T-VLF BGRM IRISH instrument and Syscal Jr. Resistivity meter. The result of the research is the distribution of manganese in resistivity< 40 ohm.m and chargeability< 10 msec. The range is used for 3D modeling and manganese volume of 228,000 m3. The manganese reserve of the research area is 984,960 ton
-
-
-
3D ERT/IP Imaging for Sulfide Mineralization over Proterozoic metavolcanics in Dhanjori Basin, Eastern Singhbhum, India
Authors A. K. Gupta, S. Srivastava and R. K. SinghSummaryThe study area, Paleoproterozoic metavolcanics in Dhanjori Basin, Eastern Singhbhum, India, is the rich source of gold associated with sulfide, quartzite veins and Quartz Pebble Conglomerate. ICP-AES analysis of samples from the study area reported the average concentration of gold, silver, copper, uranium, magnetite, lead and zinc as 5ppm, trace, 110 ppm, 50 ppm, 1.5 ppm, 6.5 ppm and 55 ppm respectively. A regional audiomagnetotellurics (AMT) study in the region indicated the presence of shallow conducting heterogeneities. This study presents the results of 3D Electrical resistivity tomography (ERT)/Induced Polarization (IP) surveys for detection of sulfide mineralization over one of these conductors identified from AMT study. The inverted model shows conducting and moderately chargeable zone as a weathered cover shallow aquifers up to 20 m depth. However, for depths more than 20 m, the lithology is broadly resistive with few conductors of small dimensions surrounding it. These are distinguished on the basis of chargeability variations from low (6mV/V) to high (90 mV/V) indicating distinct geological features such as massive sulfide, QPC/quartz vein with disseminated sulfide gold, greenstone schist, and dolerite dike/Proterozoic gabbro anorthosite mass. The future scout drilling program has been concentrated on the identified zones of sulfide mineralization.
-
-
-
Manganese Mineral Exploration in Kulon Progo District Using Induced Polarisation Method
Authors G. Erlangga, I. Arifianto and K. AfafaSummaryKliripan and Anjir Sub-village, Kulon Progo district were known as one of big manganese mining in Java island, but a big scale mining on the surface is uneconomic anymore. Based on the geological setting, there is a chance to discover a new deposit resource in the subsurface. Therefore, manganese exploration using induced polarisation method had been done in this area. Data acquisition was obtained by utilizing Syscal Jr. with 10 – 20 meter electrode spacing, and n=6. The data was processed to delineate a prospect zone of manganese mineralisation. Resistivity and chargeability of manganese are considered in the interpretation. Mineralisation zones of manganese are clearly seen at the second and third line. From the reference, manganese minerals have a 135 – 250 msec chargeability value. On the second line, the mineralized zone is located at 65 meters above sea level and distance of 250 meters on section line. While mineralisation zone in the third line is located at 70 meters above sea level and a distance of 110 meters on the section line, both of them are at Anjir Sub-village. The mineralisation zone is guessed potential as a manganese hill associate with limestone deposit, refer to the outcrop at surface.
-
-
-
Remote Sensing Application in Exploration of Iron Mineral Placer Deposit: Case Study of Kulonprogo’s Iron Placer Deposit
Authors I. D. Putra, R. Abbas, S. D. Masti and I. W. WarmadaSummaryIndonesia is a country of Island arcs setting, tectonically. This setting has induced many of volcanoes Indonesia followed by the presence of mineral deposits. As the consequences of never-ending demand for ore minerals, exploration of mineral deposits are always needed. The study area is located in Kulonprogo, Yogyakarta. The study area is marked by secondary type mineral deposit presence of Placer type. Several band combinations analysis of Landsat 8 OLI/ TIRS 432, 567, and rationing of band 5/6 and 4/2 are done as methods in order to reveal the geological, and geomorphological conditions of the study area and the dissemination of iron-bearing mineral in the source and in the secondary deposit. The result of the analysis is the dissemination of the iron-bearing mineral are present covered wide area within and around the Glagah beach, the iron mineral source are located several kilometers to the north, the transportation of iron-bearing mineral is done through fluvial mechanisms of Serang and the other River to the beaches in the south. Some factors are also expected to affect the deposition processes, such as mineral density, waves, and river’s current speed. From this study, it’s believed that remote sensing is useful “tool” in mineral exploration.
-
-
-
The Potential Development of Rajabasa Geothermal Manifestations in Kalianda Into Geoturism Area in South Lampung
Authors M. Addiansyah, R.D. Linggadipura, A. Krestanu and M.H. PrasetyoSummaryKalianda has very interesting geological phenomena that evidenced by the existence a several manifestations of Mount Rajabasa Geothermal System those became the research object of geoturism area development. The research methods are field observation, studio analysis, and quantitative analysis of geosite and geomorphosite based on Kubalikova (2013 ) to assess the development potential of Kalianda into geoturism area. Parameters of quantitative analysis of geosite and geomorphosite that used are scientific and intrinsic value, educational value, economic value, conservation value, and additional value. Based on the results of field observation and quantitative assessment towards geological objects located in Kalianda and surrounding area, six geological objects that are potential to become geosites and geomorphosite. Those are Rajabasa Volcanic 65.1%, Maribung Waterfall 46.6%, Way Kunjir Geyser and Hot Spring 45.9%, Wartawan Beach 72.5%, Belerang Simpur Hot Spring 66.6%, and Way Belerang Hot Spring 65.2%. Those data indicate that Kalianda Area has potential to become geotourism area geoscience field campus with volcanology, geothermal, and oceanography learning aspects. In order to optimize the operational geoturism area needs to be equipped with cleanliness facilities, lodging, and scientific sign board. Kalianda Geoturism Area development is believed will improve the economy of the community around Kalianda Area.
-
-
-
Estimation of average electromagnetic wave velocity in tree trunks for the reflection imaging by GPR
Authors K. Takahashi and K. AoikeSummaryWe developed a simple method to estimate average propagation velocity of electromagnetic waves in tree trunks. The method employs GPR transmission measurements that fixes the transmitting antenna and scans receiving antenna circumferentially on the perimeter of a trunk. The data exhibit an arrival time curve since the measurement configuration consists of various propagation lengths. We modified the velocity analysis of CMP measurement and calculate semblance as a function of relative permittivity (or velocity). The maximum semblance indicates the permittivity value that best describes the arrival time curve in the transmission data and the value is the estimation. We demonstrate the method with a laboratory experiment with a drilled log and that the estimated permittivity gives better reflection image than other values.
-
-
-
Earth Material as Supporting Tool in Legal Case Investigation and the Role of Geoscientist in Disclosing the Criminal
More LessSummaryForensic geology is defined as the application of earth science in the field of law (Munroe, 2002). Forensic geology to date still sounds foreign, especially in Indonesia. Whereas the application of forensic geology can be a reinforcement tool in law enforcement processes. The background of the use of earth’s material as an instrument of investigation is the variety of materials of this earth, such as soil, lithology, minerals, fossils. The diversity ranging from physical, biological to chemical, such as size, color, shape, composition, and mineralogy. In this modern era, tools have been able to identify such materials as using polarization microscopes for microscopic observation. Another thing that underlies the application of forensic geology is the assumption that any contact with the earth’s material will result in a trace of the perpetrator, the victim, the object, or the scene of the case which then identified the material, its origin, similarities with other areas, and so on. This becomes a great potential in the law enforcement process, and becomes a supporting tool to unravel the mystery of the criminals. Here the geoscientist’s role is needed to identify and observe the earth’s material and Indonesia has many reliable geoscientist to solve the problem.
-