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Geothermal energy is considered renewable energy that is environmentally friendly and sustainable compared to the conventional energy from fossil fuels. However, uncontrolled geothermal exploitation can cause a decrease in the groundwater table and reservoir temperature, such as in the Jaboi volcano on Weh Island, where a power plant has been built to generate electrical energy with an estimated power of 50 MWe but still has not been operated. A geophysical survey is needed to determine the local hydrothermal system, including groundwater reserves under the surface which can be used to refill the hydrothermal wells during exploitation. This study measured vertical electrical sounding (VES) data at 15 points near the crater and geothermal power plant. In addition, very-low-frequency (VLF) data that pass through the crater were also collected to determine the presence of other hydrothermal resources such as fractures and faults. The results of the 1D least-square inversion show three subsurface models where groundwater resources with low resistivity (< 1.5 Ωm) are found at a depth of 50–100 m. The same results are also obtained from the 2D cross-section model that impermeable resistive anomalies in alluvial and tuff rocks dominate the near-surface area. The layer after groundwater is an impermeable rock in the form of breccia. The results of 2D VES and VLF modeling also show the presence of the Ceunohot and Leumomate faults, which are beneficial as fluid access to the surface. Based on the data analysis, the combination of VES and VLF data can be used to image shallow hydrothermal systems such as groundwater resources and faults in the Jaboi volcano. [ABSTRACT FROM AUTHOR]

Since the 21st century, Lamreh, Aceh Besar Regency, Indonesia played an important role during the maritime silk route at the gate of the Malacca strait. This article investigates the subsurface structure of landslide-prone areas in cultural heritage based on 2D resistivity, chargeability and current density models of ERT, IP and VLF-EM methods, respectively. Field data measurements were carried out on 2 crossing profiles along the cliff suspected of experiencing landslides. The length of each profile is 220 with 4 m distance between stations. The 2D models reveal that the subsurface geological structure of Lamreh is composed of a mixed layer of clastic sediment and volcanic material at the top, followed by a layer of calcareous sandstone, and volcanic breccia at the bottom. The 3 layers are most easily distinguished in the resistivity model. The topmost layer is permeable but dry, i.e., characterized by a more resistive layer in the models. While the second layer is characterized by an intermediate conductivity and the bottom layer is highly conductive. The conductivity in these 2 layers is influenced by the degree of water content within the rocks. The chargeability models derived from IP data can distinguish between the dry layer on the surface and the saturated layer below. Meanwhile, the current density models obtained from VLF-EM data have proven the presence of fractures and faults along the profiles due to weathering as also seen in the resistivity models. [ABSTRACT FROM AUTHOR]

The Great Sumatran Fault activity on Sumatra Island has presented a series of volcanoes and geological landscapes that can be developed as geo-tourism potential, such as in Iboih. The Weh Island has many natural tourism potentials that can be used to improve the community's income directly and as lessons learned for the dangers of living in a volcanic environment. The conventional method of delivering information is through a guide to visitors. This is very limited to the guide's ability to explain the phenomenon of tourist sites and the relation to lessons learned. In this study, we use the integration of QR-Code and web-based technology to develop a digital tourism system that can provide unlimited information to visitors and can be managed efficiently by the public. The data analysis shows that a QR code information board integrated with a web-based programming system can be used to monitor the number of monthly visitors at each tourism site. In addition, the java-script integration on the QR code board can present information that can be changed through links, images or videos without reprinting the QR-code model. Furthermore, we also present important locations from Iboih Village in the form of Web-GIS, such as tourist locations, road access, public infrastructure and food locations that tourists can easily access. Based on the research, we conclude that integrating QR-code and web-based programming can be an effective tool in tourism development as a medium for lessons learned by the community. [ABSTRACT FROM AUTHOR]

Wind energy is renewable energy used as an energy source for wind power plants (PLTB). The most common distribution method used to model wind speed distribution data is the Weibull distribution. The Nakagami distribution has begun to be widely used in several studies to model wind speed distribution data. The Nakagami distribution is considered an alternative to the Weibull distribution in modeling wind speed distribution data. This study aims to compare the distribution of Nakagami and Weibull in analyzing wind power potential and calculating the resulting Wind Energy Production (WEP), using wind speed distribution data from both distributions in Kuta Raja, Banda Aceh and Lhoknga, Aceh Besar. The wind speed data used is satellite data (secondary data) downloaded via windguru.cz, with the most stable wind speed being a wind speed of 3-5 m/s. The value of wind power potential at the Kuta Raja location, Banda Aceh was obtained at 64.16% with the Nakagami distribution and 62.73% with the Weibull distribution, and 73.60% with the Nakagami distribution and 73.28% at the Lhoknga location, Aceh Besar. The comparison of these two distributions produces a Weibull distribution that is superior to the Nakagami distribution for both locations, where the Weibull distribution has a smaller error value and produces a WEP value that is in accordance with the actual/observable data compared to the Nakagami distribution. In this study, the Nakagami distribution has results that make this distribution an alternative or comparison to the Weibull distribution in distributing wind speed data with further research. [ABSTRACT FROM AUTHOR]

Geothermal energy, as a part of green and renewable energy, has been widely developed in the world to replace the current conventional fossil energy. Peut Sagoe is an active volcano in the northern part of Sumatra. The volcanic mountain has not been completely explored for geothermal and energy reserves study. This is due to the volcano locates in a high topography and surrounded by dense tropical forest, which makes it challenging to deploy geophysical instruments in the area. The Landsat 8 thermal infrared and meteorological data from 2013 – 2020 were used to estimate the energy resources by calculating the radiative heat flux (RHF) and measuring the energy lost annually through the heat discharge rate (HDR). We also used the normalized differential vegetation index (NDVI) for vegetation analysis, and estimation of its emissivity data. The mono-window algorithm was used to calculate the land surface temperature (LST). The Stefan–Boltzmann equation was utilized to analyze thermal infrared data for RHF, and ambient temperature and relative humidity data were acquired from the Indonesian Meteorological Agency (BMKG) database. The results showed that low vegetation values and high LST of 25°C–35°C were found in crater areas, which indicate the underground thermal activities of the mountain. It demonstrates that the maximum RHF values were 55 W/m² in 2013 and 37 W/m² in 2020. The HDR data were calculated by applying 15% of the RHF data, and the amounts of energy lost were 132.5 MWe and 64.5 MWe in 2013 and 2015 respectively. It increased to 186.4 MWe in 2017 and 89 MWe in 2020. Based on these predicted results, we conclude that the combination of thermal infrared imagery of Landsat 8 and meteorological data is an effective approach in estimating geothermal energy potential and energy loss of volcanoes situated in remote areas. [ABSTRACT FROM AUTHOR]

Indonesia's Aceh Province is an earthquake-prone area due to its location on the Great Sumatran Fault (GSF). Currently, earthquake mitigation by the local government constantly refers to the regional seismic hazard maps. However, some sources of an earthquake in the province which had caused damage to buildings and loss of human life were not easily traced to the fault on the surface. Currently, the mapping activities related to the Sumatra fault lines are only focused on the mainland. In contrast, the continuity of the GSF fault in the area of the sea and surrounding islands is very rarely studied. Weh Island is inhabited by many communities and has become a popular tourism area. This study aims to map the regional and local fault structure on the Weh Island using the gravity model plus (GGMPlus) data. We used the GGMPlus data with a resolution of 200 m for detailed mapping of regional and local faults. The 3D inversion of the GGMPlus data was carried out to obtain density parameters using two models, namely Singular Value Decomposition (SVD) and Occam optimization. The 3D inversion describes the presence of high-density rock blocks. A density value ranging between 2.72 - 2.96 gr/cm³ is interpreted as rocks with andesite-basaltic lava composition and lava or pyroclastic breccias resulting from local volcanic products as the rocks creating the island. Therefore, the zone interpreted as a local fault had a smaller density value (2.5 - 2.65 gr/cm³) than the surrounding. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]