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Risnaliyah Nuriil T - One of the best experts on this subject based on the ideXlab platform.

  • APLIKASI METODE GRAVITASI DALAM PERENCANAAN PEMBANGUNAN TEROWONGAN KULU, LHOONG, ACEH BESAR
    'Fakultas Teknik Elektronika dan Komputer Universitas Kristen Satya Wacana', 2018
    Co-Authors: Risnaliyah Nuriil T
    Abstract:

    ABSTRAKSurvei metode Gravitasi telah dilakukan di daerah rencana pembangunan terowongan dikawasan Gunung Kulu, lhoong, Aceh Besar untuk menentukan kondisi geologi struktur bawah permukaan. Nilai percepatan gravitasi telah diukur menggunakan metode gravitimeter Scrintex CG-5. Pengukuran dilakukan dengan panjang lintasan 1.6 Km. data diukur secara berurut dengan jarak spasi 25 cm dan jumlah titik 54. Untuk mendapatkan nilai Anomali Bouguer Lengkap, beberapa koreksi yang dilakukan yaitu koreksi drift, koreksi pasar surut, koreksi lintang,koreksi udara bebas, koreksi Bouguer, dan koreksi medan. Data nilai Anomaly Bouguer lengkap sepanjang profil digunakan untuk pemodelan maju Batuan kedua merupakan batuan gunung api vulkanik yaitu basalt dengan nilai densitas 3,24 gr/cm 3 Batuan ketiga merupakan batuan lempung 3Kata Kunci : Metode Gravitasi, Grav2DC, Terowongan, Gunung Kulu, Densitas 3ABSTRACTSurvey of gravity method has been done in the tunnel development area plan in area Kulu Mountain, Lhoong, Aceh Besar for determine geology structurecondition under the surface area. gravity acceleration of value has been measured by using gravitimeter Scrintex CG-5 instrument. The measurement were carried out in 1.6 km length track. The data were measured sequentially on 25 cm spaceddistance with 54 point. In order to obtain a Complete Bouguer Anomaly value,some corrections were applied, that is drift correction, Tidal correction,latitude correction, free air correction, Bouguer correction, and terraincorrection. Complete Bouguer Anomaly value data along the profile were use for2D forward modeling using Grav2DC software. The model shows that subsurfacecondition there was three types of rocks. The first is precipitaterock 3 density. The second is Mountain fire volcanic rock is basalt with 3,24 gr/cm 3density value. And the third is clay rock with 1,7 gr/cm 3 density .Keywords: method gravity , Grav2DC, Tunnel , Kulu Mountain, DensityBanda Ace

  • APLIKASI METODE GRAVITASI DALAM PERENCANAAN PEMBANGUNAN TEROWONGAN KULU, LHONG ACEH BESAR
    'Fakultas Teknik Elektronika dan Komputer Universitas Kristen Satya Wacana', 2018
    Co-Authors: Risnaliyah Nuriil T
    Abstract:

    Survei metode Gravitasi telah dilakukan di daerah rencana pembangunan terowongan dikawasan Gunung Kulu, lhoong, Aceh Besar untuk menentukan kondisi geologi struktur bawah permukaan. Nilai percepatan gravitasi telah diukur menggunakan metode gravitimeter Scrintex CG-5. Pengukuran dilakukan dengan panjang lintasan 1.6 Km. data diukur secara berurut dengan jarak spasi 25 cm dan jumlah titik 54. Untuk mendapatkan nilai Anomali Bouguer Lengkap, beberapa koreksi yang dilakukan yaitu koreksi drift, koreksi pasar surut, koreksi lintang, koreksi udara bebas, koreksi Bouguer, dan koreksi medan. Data nilai Anomaly Bouguer lengkap sepanjang profil digunakan untuk pemodelan maju (foerward modelling) 2D menggunakan sofware Grav2DC. Hasil permodelan menunjukan bahwa kondisi bawah permukaan memliki tiga jenis batuan. Batuan pertama merupakan batuan endapan (Alluvium) dengan densitas 1,93 gr/cm3. Batuan kedua merupakan batuan gunung api vulkanik yaitu basalt dengan nilai densitas 3,24 gr/cm3. Batuan ketiga merupakan batuan lempung (clay) dengan densitas 1,7 gr/cm3.Kata Kunci : Metode Gravitasi, Grav2DC, Terowongan, Gunung Kulu, DensitasSurvey of gravity method has been done in the tunnel development area plan in area Kulu Mountain, Lhoong, Aceh Besar for determine geology structure condition under the surface area. gravity acceleration of value has been measured by using gravitimeter Scrintex CG-5 instrument. The measurement were carried out in 1.6 km length track. The data were measured sequentially on 25 cm spaced distance with 54 point. In order to obtain a Complete Bouguer Anomaly value, some corrections were applied, that is drift correction, Tidal correction, latitude correction, free air correction, Bouguer correction, and terrain correction. Complete Bouguer Anomaly value data along the profile were use for2D forward modeling using Grav2DC software. The model shows that subsurface condition there was three types of rocks. The first is precipitate rock (Alluvium) with 1,96 gr/cm3 density. The second is Mountain fire volcanic rock is basalt with 3,24 gr/cm3 density value. And the third is clay rock with 1,7 gr/cm3 density .Keywords: method gravity , Grav2DC, Tunnel , Kulu Mountain, DensityBanda Ace

Andrew Y. Glikson - One of the best experts on this subject based on the ideXlab platform.

  • gnargoo a possible 75 km diameter post early permian pre cretaceous buried impact structure carnarvon basin western australia
    Australian Journal of Earth Sciences, 2005
    Co-Authors: Robert P. Iasky, Andrew Y. Glikson
    Abstract:

    The Gnargoo structure is located on the Gascoyne Platform, Southern Carnarvon Basin, Western Australia, and is buried beneath about 500 m of Cretaceous and younger strata. The structure is interpreted as being of possible impact origin from major geophysical and morphometric signatures, characteristic of impact deformation, and its remarkable similarities with the proven Woodleigh impact structure, about 275 km to the south on the Gascoyne Platform. These similarities include: a circular Bouguer Anomaly (slightly less well-defined at Gnargoo than at Woodleigh); a central structurally uplifted area comprising a buried dome with a central uplifted plug; and the lack of a significant magnetic Anomaly. Gnargoo shows a weakly defined inner 10 km-diameter circular Bouguer Anomaly surrounded by a broadly circular zone, ∼75 km in diameter. The north – south Bouguer Anomaly lineament of the Giralia Range (a regional topographic and structural feature) terminates abruptly against the outer circular zone which is, i...

Glikson Andrew - One of the best experts on this subject based on the ideXlab platform.

  • Gnargoo: a possible 75 km-diameter post-Early Permian - pre-Cretaceous buried impact structure, Carnarvon Basin, Western Australia
    Blackwell Publishing Ltd, 2015
    Co-Authors: Iasky R, Glikson Andrew
    Abstract:

    The Gnargoo structure is located on the Gascoyne Platform, Southern Carnarvon Basin, Western Australia, and is buried beneath about 500 m of Cretaceous and younger strata. The structure is interpreted as being of possible impact origin from major geophysical and morphometric signatures, characteristic of impact deformation, and its remarkable similarities with the proven Woodleigh impact structure, about 275 km to the south on the Gascoyne Platform. These similarities include: a circular Bouguer Anomaly (slightly less well-defined at Gnargoo than at Woodleigh); a central structurally uplifted area comprising a buried dome with a central uplifted plug; and the lack of a significant magnetic Anomaly. Gnargoo shows a weakly defined inner 10 km-diameter circular Bouguer Anomaly surrounded by a broadly circular zone, ∼75 km in diameter. The north-south Bouguer Anomaly lineament of the Giralia Range (a regional topographic and structural feature) terminates abruptly against the outer circular zone which is, in turn, intersected on the eastern flank by the Wandagee Fault. A < 28 km-diameter layere sedimentary dome of Ordovician to Lower Permian strata, surrounding a cone-shaped, central uplift plug of 7-10 km diameter, are inferred from the seismic data, Seismic-reflection data indicate a minimum central structural uplift of 1.5 km, as compared to a model uplift of 7.3 km calculated from the outer structural diameter, An interpretation of Gnargoo in terms of a plutonic or volcanic caldera/ring origin is unlikely as these features display less regular geometry, are typically smaller and no volcanic rocks are known in the onshore Gascoyne Platform. An interpretation of Gnargoo as a salt dome is likewise unlikely because salt structures tend to have irregular geometry, and no extensive evaporite units are known in the Southern Carnarvon Basin. Morphometric estimates of the rim-to-rim diameter based on seismic data for the central dome correspond to the observed diameter deduced from gravity data, and fall within the range of morphometric parameters of known impact structures. The age of Gnargoo is constrained between the deformed Lower Permian target rocks and unconformably overlying undeformed Lower Cretaceous strata. Because of its large dimensions, if Gnargoo is an impact structure, it may have influenced an environmental catastrophe during this period

David M.h. Baker - One of the best experts on this subject based on the ideXlab platform.

  • grail gravity observations of the transition from complex crater to peak ring basin on the moon implications for crustal structure and impact basin formation
    Icarus, 2017
    Co-Authors: Gregory A Neumann, David E Smith, J W Head, David M.h. Baker, Roger J Phillips, C J Bierson, Maria T Zuber
    Abstract:

    Abstract High-resolution gravity data from the Gravity Recovery and Interior Laboratory (GRAIL) mission provide the opportunity to analyze the detailed gravity and crustal structure of impact features in the morphological transition from complex craters to peak-ring basins on the Moon. We calculate average radial profiles of free-air anomalies and Bouguer anomalies for peak-ring basins, protobasins, and the largest complex craters. Complex craters and protobasins have free-air anomalies that are positively correlated with surface topography, unlike the prominent lunar mascons (positive free-air anomalies in areas of low elevation) associated with large basins. The Bouguer gravity Anomaly profiles of complex craters are highly irregular, with central positive anomalies that are generally absent or not clearly tied to interior morphology. In contrast, gravity profiles for peak-ring basins (∼200 km to 580 km) are much more regular and are highly correlated with surface morphology. A central positive Bouguer Anomaly is confined within the peak ring and a negative Bouguer Anomaly annulus extends from the edge of the positive Anomaly outward to about the rim crest. A number of degraded basins lacking interior peak rings have diameters and gravity patterns similar to those of well-preserved peak-ring basins. If these structures represent degraded peak-ring basins, the number of peak-ring basins on the Moon would increase by more than a factor of two to 34. The gravity anomalies within basins are interpreted to be due to uplift of the mantle confined within the peak ring and an annulus of thickened crust between the peak ring and rim crest. We hypothesize that mantle uplift is influenced by interaction between the transient cavity and the mantle. Further, mascon formation is generally disconnected from the number of basin rings formed and occurs over a wide range of basin sizes. These observations have important implications for models of basin and mascon formation on the Moon and other planetary bodies.

  • Lunar impact basins revealed by Gravity Recovery and Interior Laboratory measurements
    Science advances, 2015
    Co-Authors: Mark A. Wieczorek, James W. Head, David M.h. Baker, Sean C. Solomon, Frank G. Lemoine, Erwan Mazarico, Terence J. Sabaka
    Abstract:

    Observations from the Gravity Recovery and Interior Laboratory (GRAIL) mission indicate a marked change in the gravitational signature of lunar impact structures at the morphological transition, with increasing diameter, from complex craters to peak-ring basins. At crater diameters larger than ~200 km, a central positive Bouguer Anomaly is seen within the innermost peak ring, and an annular negative Bouguer Anomaly extends outward from this ring to the outer topographic rim crest. These observations demonstrate that basin-forming impacts remove crustal materials from within the peak ring and thicken the crust between the peak ring and the outer rim crest. A correlation between the diameter of the central Bouguer gravity high and the outer topographic ring diameter for well-preserved basins enables the identification and characterization of basins for which topographic signatures have been obscured by superposed cratering and volcanism. The GRAIL inventory of lunar basins improves upon earlier lists that differed in their totals by more than a factor of 2. The size-frequency distributions of basins on the nearside and farside hemispheres of the Moon differ substantially; the nearside hosts more basins larger than 350 km in diameter, whereas the farside has more smaller basins. Hemispherical differences in target properties, including temperature and porosity, are likely to have contributed to these different distributions. Better understanding of the factors that control basin size will help to constrain models of the original impactor population.

Fhatihatul Rahmi - One of the best experts on this subject based on the ideXlab platform.

  • Analisis SBA (Simple Bouguer Anomaly) Sebelum Gempa Padang Panjang 6 Maret 2007
    2021
    Co-Authors: Fhatihatul Rahmi
    Abstract:

    Telah dilakukan penelitian mengenai analisis SBA (Simple Bouguer Anomaly) sebelum gempa Padang Panjang 6 Maret 2007 yang bertujuan untuk melihat adanya korelasi antara perubahan anomali gravitasi dengan kejadian gempa bumi. Data gravitasi yang digunakan adalah data dari satelit GRACE (Gravity Recovery And Climate Experiment). Metode yang digunakan adalah metode time-lapse microgravity. Hasil kontur anomali selisih SBA menunjukkan adanya polarisasi anomali gravitasi yang terjadi di sekitar episenter gempa pada 35 hari sebelum gempa. Terdapat zona anomali tinggi di bagian tenggara dan zona anomali rendah di bagian barat daerah penelitian. Berdasarkan hasil sayatan melintang pada kontur harian SBA, diperoleh nilai harian SBA dan grafik harian SBA yang menunjukkan penurunan secara perlahan dari 35 hari hingga 20 hari sebelum gempa. Penurunan maksimum terjadi pada tanggal 12 Februari 2007. Lalu diikuti kenaikan secara terus menerus dari 20 hari hingga 15 hari sebelum gempa. Berdasarkan grafik selisih harian SBA, pada 35 hari sebelum gempa muncul anomali medan gravitasi tanggal 28 Januari 2007 dengan perubahan anomali gravitasi maksimum dari tanggal 22 – 23 Februari 2007 sebesar 0,490763281 µgal pada titik episenter gempa magnitudo 6,4 dan sebesar 0,49639576 µgal pada titik episenter gempa magnitudo 6,3. Sehingga anomali yang muncul tersebut dapat dijadikan pertanda awal (prekursor) gempa bumi