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Dimensionality Analysis of Magnetotelluric Data Crossing the Sumatran Fault System at Aceh Segment Khumaidi Khumaidi; Fadhli Fadhli; Nazli Ismail
Jurnal Natural Volume 13, Number 2, September 2013
Publisher : Universitas Syiah Kuala

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Dimensionality of magnetotelluric transfer functions have been analyzed crossing the Sumatran Fault System at Aceh segment. The research was aimed to determine strike direction of the fault system using magnetotelluric transfer function data. We used Phoenix Geophysics MTU-5A equipment in range frequency 5A equipment in range frequency 0.86-320 Hz for data measurement. Collection of data was performed along two profiles with spacing between stations vary from 7 to 80 Km. The first profile started 94.5 Km from Aceh Jaya District and ended at Pidie District. The second profile started 16.5 Km from Aceh Jaya District and ended at Bireuen District.The data were analyzed by using Zhang et al. (1989) method to calculate Swift's skew and strike direction. Based on the calculation, we found that the Swift's skew values were generally less than 0.1, which were usually the overall structure of local and regional and they could be viewed as a 1D or 2D, and the values above 0.1 were considered as 3D effects or noises. Furthermore, the average strike has 0º or 90º angle. The data showed that geoelectrical strikes of both profiles were in agreement with the geological structure of the fault system. In order to get image of the 2D resistivity model of the area, we had inverted the magnetotelluric data showed that geoelctrical strikes of both profiles were in agreement with the geological structure of the fault system. In order to get image of the 2D resistivity model of the area, we had inverted the magnetotelluric data using MT2DinvMatlab (Lee et al., 2009). The model showed clearly position and depth of the fault lines along the profiles.

GROUND-WATER RESOURCES ASSESSMENT USING GEOPHYSICAL VLF METHOD: A CASE STUDY FROM WATER RESOURCES ASSESSMENT USING GEOPHYSICAL VLF METHOD: A CASE STUDY FROM WATER RESOURCES ASSESSMENT USING GEOPHYSICAL VLF METHOD: A CASE STUDY FROM COASTAL URBAN FOREST Nazli Ismail
Jurnal Natural Volume 13, Number 2, September 2013
Publisher : Universitas Syiah Kuala

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In urban areas, there is not only a heavy reliance on ground water as a primary drinking supply but is also as a supply of water for both agriculture and industrial uses. The reliance on ground water is necessary to ensure that there are significant quantities and high quality of water. Ground water resources at coastal urban forest in Banda Aceh were assessed by using VLF method. VLF techniques measured the perturbations in a plane wave radio signal (15-30 kHz) being emanated from one of several world-widde radio transmitters and was also used for submarine communications. Apparent resistivities and phases were measured along 340 m profile at the area. Two frequencies (27700 and 29000 Hz) were used in this measurement. The data were modeled by using 2D inversion code of Rebocc. The model showed clearly ground-water map of the subsurface. Based on the model, aquifer layers were indicated by low resistivities zones (40 – 400 Ω-m). However, the ground-water resources in the area were dominated with high salinity water at depth under 140 m. Therefore, extended geophysical exploration methods were water aquifer in the area to watering the forest.

IMPORTANCE OF LOCATING STRIKE IN 2D MAGNETOTELLURIC DATA MODELING Nazli Ismail
Jurnal Natural Volume 13, Number 1, March 2013
Publisher : Universitas Syiah Kuala

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2D inversion is still believed as the fastest, cheapest, and most reliable method magnetotelluric data interpretation. Traditionally the magnetotelluric data are collected on 2D profile perpendicularly across an assumed geological strike. However there is no guarantee where the chosen strike is exactly or nearly same as true geoelectrical strike. For this purpose, 2D synthetic magnetotelluric impedance data of a simple 2D model were generated along a profile across the model. The data were inverted on various presumed strike in order to study how far the inverted model is deviated when the presumed strike is moved away to the true strike. By the aim, first the data were inverted as measured on 2D profile perpendicularly across true strike in order to see how the inversion works in the ideal case. Thedata were also inverted as measured on 2D profile perpendicularly across an assumed strike. The presumed strike deviated 60 degrees to the true strike was selected as an example of extreme case. The model inverted from the extreme presumed strike data is compared to the actual one. The inversions on determinant and combined TE and TM modes have been done as well for model resolution comparison.

THE DIFFERENT MAGNETIC RESULTS OF ANEMI AND PPM MEASUREMENTS ON THE BURIED REMAINS OF A 13TH CENTURY FORTRESS Muhammad Yanis; Marwan Marwan; Bukhari Bukhari; Nazli Ismail
Jurnal Natural Volume 16, Number 2, September 2016
Publisher : Universitas Syiah Kuala

This study aimed to evaluate the different magnetic results of an electromagnetic induction with proton magnetometer measurements on an archaeological site. The electromagnetic induction allows measuring both the apparent magnetic susceptibility in part per thousand (ppt) and the apparent electrical conductivity in millisiemens (mS/m). A proton magnetometer measures the total magnetic intensity in nanotesla (nT), caused by the induced and remanent magnetisations. An archaeological site where historical documents indicated the presence of a 13th century fortress that built by Lamuri Sultanate was selected as a test area. The measurement were conducted by divided the study area into 10 profiles.Some standard data processing have been applied to the measured data. The result of the first survey with electromagnetic induction showed low magnetic anomalies in the buried remains of Lamuri fortress. The similar value are shown as well by low magnetic field intensity in magnetometer measurement.

Application of magnetic method for mapping buried structures around archaeological site of Masjid Tuha Indrapuri CUT INTAN KEUMALA; TOMI AFRIZAL; MUHAMMAD SYUKRI SURBAKTI; NAZLI ISMAIL
Jurnal Natural Volume 20 Number 2, June 2020
Publisher : Universitas Syiah Kuala

Magnetic gradiometer survey has been conducted on the yard of the archaeological site of Masjid Tuha Indrapuri, Aceh Besar Regency, Aceh Province. The site is one of the oldest mosques erected during the Aceh Sultanate period. Magnetic method was applied for mapping archaeological structures buried beneath the surface. Total magnetic field data were measured using Proton Precession Magnetometer with grid spacing of 2 meters between stations covering the entire area of the site. Diurnal and international geomagnetic reference field data were corrected to the measured data in order to calculate total magnetic field anomalies that were influenced by the buried magnetic objects. The total magnetic field anomalies distribution shows two elongated structures with U-shaped patterns surrounding the mosque. The patterns are also revealed in reduction to the pole and derivative vertical filters of the total field anomaly data. The anomaly patterns are considered a response from the rest of the buried fences that were built around the mosque in the past.

Application of gravity method in cultural harritage Cot Sidi Abdullah Site, Samudera Pasai, North Aceh NOVIA PURNAMA SARI; TOMI AFRIZAL; FAISAL ABDULLAH; NAZLI ISMAIL
Jurnal Natural Volume 20 Number 3, October 2020
Publisher : Universitas Syiah Kuala

The gravity method was applied to the cultural heritage site of Cot Sidi Abdullah in Kuta Krueng Village, Samudera Pasai District, North Aceh Regency for mapping and reconstruction structure of the cultural heritage site and distribution of artifact objects buried in the subsurface. Data measurement was carried out in a grid with 2 meters spacing between the points to cover all area of the cultural heritage site. The model of gravity anomaly distribution from the vertical derivative results shows a square pattern of anomaly gravity surrounding the measurement areas. This anomaly pattern is thought as a response from the remaining walls of the site structure which are buried in the subsurface with anomalous values between 0.02 mGal/m - 0.08 mGal/m. The estimation of the walls of the archaeological site from the anomalous response to this gravity value is proved by the excavation results in the southern part of the study area. While the minimum value of the vertical derivative filter (-0.06 mGal/m to - 0.01 mGal/m) is the response from the area around the archaeological site. The reconstruction results of the site based on the estimation of the walls with a length of ± 45 meters and a width of ± 40 meters.

TREND ANALYSIS OF EXTREAM RAINFALL FROM 1982 - 2013 AND PROJECTION FROM 2014 - 2050 IN BANDA ACEH AND MEULABOH Farid Mufti; Nazli Ismail; Muksin Umar
Jurnal Natural Volume 17, Number 2, September 2017
Publisher : Universitas Syiah Kuala

Abstract. Climate change is a global phenomenon that currently and seriously impacts the environment. Increasing concentrations of greenhouse gases have caused changes in extreme climate events. We have studied index rainfall extream trend at two meteorological stations of Sultan Iskandar Muda in Banda Aceh and Cut Nyak Dien in Meulaboh from 1982-2013. Daily rainfall data were processed using software of RClimDex to obtain the extreme rainfall index. Such indexes are extreme climate index set by the expert team for Climate Change Detection Monitoring and Indices (ETCCDMI) including of maximum 1-day and 5-days precipitation amount (RX1day and RX5day), total annual precipitation (PRCPTOT), consecutive dry days (CDD), consecutive wet days (CWD), very wet days (R95p), extremely wet days (R99p) and heavy precipitation days (R20mm). Based on our study, we found that the PRCPTOT tend to decrease, whereas occurances of RX1day and RX5day increase. The Banda Aceh station which has a monsoonal pattern is charaterized by increasing in R95p and R99p as well as but decreasing in R20mm. The CWD and CDD tend to accumulate at once. The Meulaboh station that has the type of equatorial rain show decreasing trend in R95p and R99p, but increasing trend in R20mm. The CWD and CDD occur within some days. The projection Representative Concentration Pathways (RCP) 4.5 and 8.5 from 2014-2050 showed an increasing pattern frequency of rain in Banda Aceh and a decreasing pattern in Meulaboh. Keywords: Trend, Extream Climate Index, ProjectionREFERENCE Lutgens. F.K. and Tarbuck. E.J. 2004. The Atmosphere: An Introduction to Meteorology. Pearson Prentice Hall. New Jersey.Ratag, M.A., Halimurrahman, Juaeni, I., Siswanto, B., dan N., Adikusumah. 2002. Perubahan Iklim : Basis Alamiah dan Dampaknya. Bandung, Lembaga Penerbangan dan Antariksa Nasional.IPCC, 2013. Climate Change. World Meteororogical Organization. Switzerland.Nuraini, Ida Sartika. 2014. Analisis dan Proyeksi Trend Temperatur dan Curah Hujan untuk Mendeteksi Perubahan Iklim (Studi Kasus Provinsi Kalimantan Barat). STMKG, Tangerang Selatan.Sulistya, W., Swarinoto, T.S., Zakir, A.,Riyanto, H., dan B., Ridwan.1998. The Impact of El Nino 1997/98 over Indonesia Region. Jakarta: Jurnal Meteorologi dan Geofisika, No 4, Desember.Zhang, X., and Feng Yang, 2004. RClimDex User Manual. Climate Research Branch, Environment Canada, Downsview, Ontario, Canada.Aldrian, E., 2007 Perubahan iklim global dan dampak terhadap iklim benua mantim di laut dan di daratan Prosiding Jumal Club Tahun 2007.Badan Meteorologi dan Geofisika. ISBN:978-979-1241-11-3

THE DIFFERENT MAGNETIC RESULTS OF ANEMI AND PPM MEASUREMENTS ON THE BURIED REMAINS OF A 13TH CENTURY FORTRESS Muhammad Yanis; Marwan Marwan; Bukhari Bukhari; Nazli Ismail
Jurnal Natural Volume 16, Number 2, September 2016
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24815/jn.v16i2.5018

This study aimed to evaluate the different magnetic results of an electromagnetic induction with proton magnetometer measurements on an archaeological site. The electromagnetic induction allows measuring both the apparent magnetic susceptibility in part per thousand (ppt) and the apparent electrical conductivity in millisiemens (mS/m). A proton magnetometer measures the total magnetic intensity in nanotesla (nT), caused by the induced and remanent magnetisations. An archaeological site where historical documents indicated the presence of a 13th century fortress that built by Lamuri Sultanate was selected as a test area. The measurement were conducted by divided the study area into 10 profiles.Some standard data processing have been applied to the measured data. The result of the first survey with electromagnetic induction showed low magnetic anomalies in the buried remains of Lamuri fortress. The similar value are shown as well by low magnetic field intensity in magnetometer measurement.

TREND ANALYSIS OF EXTREAM RAINFALL FROM 1982 - 2013 AND PROJECTION FROM 2014 - 2050 IN BANDA ACEH AND MEULABOH Farid Mufti; Nazli Ismail; Muksin Umar
Jurnal Natural Volume 17, Number 2, September 2017
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24815/jn.v17i2.7012

Abstract. Climate change is a global phenomenon that currently and seriously impacts the environment. Increasing concentrations of greenhouse gases have caused changes in extreme climate events. We have studied index rainfall extream trend at two meteorological stations of Sultan Iskandar Muda in Banda Aceh and Cut Nyak Dien in Meulaboh from 1982-2013. Daily rainfall data were processed using software of RClimDex to obtain the extreme rainfall index. Such indexes are extreme climate index set by the expert team for Climate Change Detection Monitoring and Indices (ETCCDMI) including of maximum 1-day and 5-days precipitation amount (RX1day and RX5day), total annual precipitation (PRCPTOT), consecutive dry days (CDD), consecutive wet days (CWD), very wet days (R95p), extremely wet days (R99p) and heavy precipitation days (R20mm). Based on our study, we found that the PRCPTOT tend to decrease, whereas occurances of RX1day and RX5day increase. The Banda Aceh station which has a monsoonal pattern is charaterized by increasing in R95p and R99p as well as but decreasing in R20mm. The CWD and CDD tend to accumulate at once. The Meulaboh station that has the type of equatorial rain show decreasing trend in R95p and R99p, but increasing trend in R20mm. The CWD and CDD occur within some days. The projection Representative Concentration Pathways (RCP) 4.5 and 8.5 from 2014-2050 showed an increasing pattern frequency of rain in Banda Aceh and a decreasing pattern in Meulaboh. Keywords: Trend, Extream Climate Index, ProjectionREFERENCE Lutgens. F.K. and Tarbuck. E.J. 2004. The Atmosphere: An Introduction to Meteorology. Pearson Prentice Hall. New Jersey.Ratag, M.A., Halimurrahman, Juaeni, I., Siswanto, B., dan N., Adikusumah. 2002. Perubahan Iklim : Basis Alamiah dan Dampaknya. Bandung, Lembaga Penerbangan dan Antariksa Nasional.IPCC, 2013. Climate Change. World Meteororogical Organization. Switzerland.Nuraini, Ida Sartika. 2014. Analisis dan Proyeksi Trend Temperatur dan Curah Hujan untuk Mendeteksi Perubahan Iklim (Studi Kasus Provinsi Kalimantan Barat). STMKG, Tangerang Selatan.Sulistya, W., Swarinoto, T.S., Zakir, A.,Riyanto, H., dan B., Ridwan.1998. The Impact of El Nino 1997/98 over Indonesia Region. Jakarta: Jurnal Meteorologi dan Geofisika, No 4, Desember.Zhang, X., and Feng Yang, 2004. RClimDex User Manual. Climate Research Branch, Environment Canada, Downsview, Ontario, Canada.Aldrian, E., 2007 Perubahan iklim global dan dampak terhadap iklim benua mantim di laut dan di daratan Prosiding Jumal Club Tahun 2007.Badan Meteorologi dan Geofisika. ISBN:978-979-1241-11-3

Application of gravity method in cultural harritage Cot Sidi Abdullah Site, Samudera Pasai, North Aceh NOVIA PURNAMA SARI; TOMI AFRIZAL; FAISAL ABDULLAH; NAZLI ISMAIL
Jurnal Natural Volume 20 Number 3, October 2020
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24815/jn.v20i3.16920

The gravity method was applied to the cultural heritage site of Cot Sidi Abdullah in Kuta Krueng Village, Samudera Pasai District, North Aceh Regency for mapping and reconstruction structure of the cultural heritage site and distribution of artifact objects buried in the subsurface. Data measurement was carried out in a grid with 2 meters spacing between the points to cover all area of the cultural heritage site. The model of gravity anomaly distribution from the vertical derivative results shows a square pattern of anomaly gravity surrounding the measurement areas. This anomaly pattern is thought as a response from the remaining walls of the site structure which are buried in the subsurface with anomalous values between 0.02 mGal/m - 0.08 mGal/m. The estimation of the walls of the archaeological site from the anomalous response to this gravity value is proved by the excavation results in the southern part of the study area. While the minimum value of the vertical derivative filter (-0.06 mGal/m to - 0.01 mGal/m) is the response from the area around the archaeological site. The reconstruction results of the site based on the estimation of the walls with a length of ± 45 meters and a width of ± 40 meters.

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