Search

Groundwater availability is the main concern in a developing region such as Weh Island, Aceh. To locate groundwater resources, vertical electrical sounding (VES) was used to identify subsurface profiles. The study area is located on a volcanic island. The lithology consists of volcanic rocks as andesite lava and pyroclastic rocks as lapily-tuff until breccia. VES method was carried out in 4 measurement points using the Schlumberger array. The resistivity value used to identify subsurface lithology. The top layer of alluvium and weathered lava have resistivity ranges from 14.3 Ωm to 17.7 Ωm with thickness varies from 0 m – 17.4 m. It is followed by andesite resistivity ranges from 17.3 Ωm to 18.2 Ωm with averages thickness is 17.4 m – 35.2 m. Finally, the bottom layer is filled by breccia-tuff with resistivity value from 5.5 Ωm to 7.3 Ωm. The physical properties of some related rocks allow water accumulation to their bodies. The current polarization indicates water content in the pore space of breecia at the study area which polarization point is identified as the water table.

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]

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]

In the northern part of Sumatra Island, Indonesia, the Great Sumatran Fault, which can cause an earthquake, was divided into two segments: the Aceh and Seulimeum. An effort to reduce the risk is mapping the fault area, especially in the region that does not clearly show the sign on the surface, e.g., in the Lamtamot area, Indonesia. Electrical resistivity is widely used to study shallow structures, but the method requires more time when applied in a large area. This research explores the potential of an extremely low frequency (very low frequency-electromagnetic; VLF-EM) method to investigate the shallow fault of the Seulimeum segment. Here, the VLF-EM is compared with other geophysical methods such as resistivity and magnetic methods. For comprehensive results, the geomorphic observation that was conducted covered outcrops of the fault and trenching sites in the geophysical study for validating the model. A similar pattern of the VLFEM and electrical resistivity data has been shown in a two-dimensional profile using data processing. The fault structure can be mapped at a distance of 20-24 m from the profile measurement, which is demonstrated by the low current density associated with the conductive zone from the VLF-EM, and low resistive anomaly in electrical resistivity. The fault can also be confirmed via magnetic intensity, which significantly increases at the same distance (20-25 m) of the VLF-EM and electrical resistivity. The geomorphic observation shows outcrops of fault activity, such as fault scarp, fractures, and faults, in the same direction as the Seulimeum segment, while scrap extends in the northwest direction up to ~20 m around the geophysical surveys. As revealed by the results, the VLF-EM method combined with other geophysical surveys and geomorphic observation can be used as a technique to image the fault that shows the shallow structure of the Seulimeum fault at 20-32 m along the profile. [ABSTRACT FROM AUTHOR]