Continuity of Great Sumatran Fault in the Marine Area Revealed by 3d Inversion of Gravity Data

Yanis, Muhammad; Yenny, Assyifa,; Zainal, Muzakir; Abubakar, Marwan; Ismail, Nahed

doi:10.11113/jurnalteknologi.v83.14824

Cited by 16 publications

(4 citation statements)

References 32 publications

(50 reference statements)

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“…Then to validate the measurement data using satellite image data. Currently, there is a lot of gravity data from satellite images, including Topex [17] and GGMPlus (Global Gravity Model Plus) [18], but in this study, validation uses GGMPlus data. Validation of field measurement data with GGMPlus uses as many as 151 data points whose positions are adjusted so that it almost coincides with the coordinates of field data.…”

Section: Gravitymentioning

confidence: 99%

Identification of Seawater Intrusion Using Geophysical Methods in the Mandalika, Lombok, Indonesia

Alaydrus¹

2022

GEOMATE

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Seawater intrusion is an event of infiltrating seawater into aquifers caused by constituent rocks that have high porosity, such as alluvial rocks. The Mandalika Lombok Indonesia is located on an alluvial plain that is very vulnerable to the occurrence of seawater intrusion. This study aims to identify areas that have been potentially affected by seawater in the Mandalika and surrounding areas. The method used is a geophysical method that combines geoelectric resistivity and gravity methods. For the data processing, we used several computer programs, namely Res2Dinv and Oasis Montaj for geoelectric data and Oasis Montaj and Grav3D for gravity data. The results of data processing are resistivity values of (0. 2 -1022.9) Ωm, residual anomaly values of (-2.7 -2. 3) mGal, and 3D model density values of (1 -3) gr/cm 3 . Based on a cross-section of 2D resistivity, the aquifer is at a depth of (2 -12) meters. There are three main layers consisting of the upper layer (Alluvium) with resistivity (18 -<100) Ωm and density value of 1.2 gr /cm 3 , the middle layer (clay sand as a shallow aquifer layer) with resistivity <18 Ωm and density value of 1.7 gr /cm 3 , then the lower layer (basement) clay with resistivity (100 -3000) Ωm and density value of 2.0 gr/cm 3 . The potential intrusion areas are located in the western part, which includes the coast of Kuta Beach and Seger Beach, and the eastern part includes the coastal area of Tanjung Aan, the Gerupuk hamlet, and the Mertak village.

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Section: Gravitymentioning

confidence: 99%

Identification of Seawater Intrusion Using Geophysical Methods in the Mandalika, Lombok, Indonesia

Alaydrus¹

2022

GEOMATE

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“…Currently, a plan to construct a 230-MWe geothermal power plant is underway. In general, the formation system of all volcanoes on the island of Sumatra is influenced by the Great Sumatra Fault's (GSF) activity that stretches some 1700 km from Lampung to the Andaman Islands of India [37][38][39]. In fact, the GSF is not an intact fault block but a collection of 20 segments dispersed across the island of Sumatra [40,41], where the Seulawah Agam volcano lies close to the Seulimeum segment leading to Pulau Weh [37,41].…”

Section: Seulawah Agam Geothermal Fieldmentioning

confidence: 99%

“…In addition, the resistive R2 anomaly is closely related to the contrast response to two local faults in the almost NW-SE direction. At this location, the fault is divided into two branches: one extending from the Ie Asam manifestation to Alue Pu, and the other the Seulimeum segment regional fault that is part of the GSF on the island of Weh Sabang [39,71].…”

Section: Two-dimensional Occam Inversionmentioning

confidence: 99%

Mapping of Fault and Hydrothermal System beneath the Seulawah Volcano Inferred from a Magnetotellurics Structure

et al. 2021

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Magnetotellurics (MT) is an important geophysical method for exploring geothermal systems, with the Earth resistivity obtained from the MT method proving to be useful for the hydrothermal imaging changes of the system. In this research, we applied the MT method to map the geothermal system of the Seulawah Agam volcano in northern Sumatra, a site intended for the construction of a geothermal power plant with an estimated energy of 230 Mwe. Herein, 3D MT measurements were carried out, covering the entire area of the volcano and the various intersecting local faults from the Seulimeum segment in the NW–SE direction. Based on Occam 2D inversion, a conductive anomaly (<10 ohm·m) near the surface was identified in response to specific manifestation areas, including the Heutsz crater on the northern side and the Cempaga crater on the southern side. A further conductive anomaly was also found at a depth of 1 km, which was presumably due to a clay cap layer covering the fluid in the reservoir layer below the surface, where the manifestation areas are formed at various locations (where faults and fractures are found) owing to the fluid in the reservoir rising to the surface. The MT modeling also revealed that the reservoir layer in Seulawah Agam lies at a depth of 2 km with a higher resistivity of 40–150 ohm·m, which is the main target of geothermal energy exploration. At the same time, the heat source zone where magma is located was estimated to lie in two locations, namely, on the northern side centering on the Heutsz crater area and the southern side in the Cempaga crater area. A clear 3D structure obtained via Occam inversion was also used to visualize the hydrothermal flow in the Seulawah Agam volcano that originates from two heat source zones, where one structure that was consistent across all models is the conductive zone that reaches a depth of 5 km in the south in response to the regional faulting of the Seulimeum segment. Based on the MT research, we concluded that the volcano has the geothermal potential to be tapped into power plant energy in the future.

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“…2), located along the active Great Sumatran Fault (GSF), which has high tectonic activity [26]. Tectonic activity from the existence of a subduction zone at the confluence of the Indo-Australian and Eurasian plates on the southern side of Sumatra, resulting in local faults [27][28]. The tectonic activity of the GSF is one of the triggers for landslides in West Sumatra [29].…”

Section: Study Area and Geological Settingsmentioning

confidence: 99%

Characterization of Landslide geometry using Seismic Refraction Tomography in the GayoLues, Indonesia

et al. 2021

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Landslides are the most common geological phenomenon in Indonesia.The event is damage to public infrastructure, and fatalities was a big impact. Therefore, mapping the geometry of landslides is a part of the mitigation effort possible by geophysical methods. In this research, we applied seismic refraction tomography (SRT) to study the geometry of the sliding zone from the landslide event.TheNational Disaster Management Authority reported that the area was frequently occurring landslide disaster, i.e. 2018, 2019 and 2020 which caused the public infrastructure and obstructed the road access from the central to the west of Aceh. The SRT was measured in two profileslong the road.Data measurements were conducted on the side of the Babahrot - GayoLues road section that had experienced landslides.Measurements were made using the Seismograph PASI 16S24-P and 24 geophones to obtain a 92-meterlong profile with 2 meter spacing between the geophones. P-wave velocity data modeling is done using ZondST2D software.The results of modeling profiles 1 and 2 describe three different subsurface layers.The SRT profile 1 model consists of slate (0.2 - 0.7 km/s), clay (0.8 - 1.3 km/s), and sandy clay (1.4 - 1.9 km/s).While, the model of profile 2 consists of slate (0.5 - 1.0 km/s), clay (1.1 - 1.6 km/ s), and sandy clay (1.7 - 2.5 km/s).The contrasting wave velocity model shows that the SRT method can be used in landslide studies as a reference in determining the mechanism of the landslide system.

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Continuity of Great Sumatran Fault in the Marine Area Revealed by 3d Inversion of Gravity Data

Cited by 16 publications

References 32 publications

Identification of Seawater Intrusion Using Geophysical Methods in the Mandalika, Lombok, Indonesia

Identification of Seawater Intrusion Using Geophysical Methods in the Mandalika, Lombok, Indonesia

Mapping of Fault and Hydrothermal System beneath the Seulawah Volcano Inferred from a Magnetotellurics Structure

Characterization of Landslide geometry using Seismic Refraction Tomography in the GayoLues, Indonesia

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