This work aimed to determine the hydrodynamics of the Malacca Strait (MS) and the part of the South China Sea (SCS). The study uses the two-dimensional numerical model with a finite-difference method. The results show that the sea surface heights in MS and the part of SCS are reversed and consistent with assimilation data that derived from Simple

The finite-difference 2D numerical model simulation was used to study the characteristics of currents, elevation, amplitude, and phase of M2-tide in the Western Waters of Aceh (WWA), Indonesia. The results show that the M2-tidal amplitude in WWA is between 14 cm and 17 cm. The lowest value is in the middle of the WWA, while the highest value is in the northwest (NW). In the southeast (SE), the amplitude is 15 cm. Phase values are in the range of 0 -40 degrees. Contour lines indicate that M2-tidal waves move from SE to NW of WWA. Current ellipses show an anticlockwise rotation. The residual currents obtained from current ellipses move from SE to NW, and this is in line with the movement of the M2-tidal wave. Based on the M2-tidal amplitude, it was concluded that the M2-tidal wave had a weak impact on tidal currents at WWA. Semi-major amplitudes of current ellipses show relatively higher value in the western part of WWA compared to the eastern part of WWA. Also, residual currents are considerably strong in the shallows near the WWA coastline.

No abstract

Bur Ni Geureudong is one of geothermal areas that potentially to be developed for geothermal power plant in Aceh Province, Indonesia. Prior to the development, detail investigation based on geological, geophysical and geochemical methods are needed for estimating its potential. However, this site is located in a mountainous area with dense forests that are difficult to reach and research of geothermal exploration in site is still very poor considering its promising potential. So that the use of remote sensing method is very suitable to be done to investigate geothermal potential in these remote areas. For reconnaissance survey, Land Surface Temperature (LST) mapping using Landsat 8 OLI/TIRS (Operational Land Imager/Thermal Infrared Sensor) image data was conducted to investigate the geothermal potential in the area. Radiometric correction, Normalized Difference Vegetation Index (NDVI) mapping and emissivity calculations were performed to obtain the LST map. Results show temperatures in the area ranged 17⁰C to 40⁰C, the area with high surface temperatures are caused by geothermal activities. NDVI map also shows an agreement with the high surface temperature region and they are mostly indicated by occurrence of vegetation stress. Keywords: Bur Ni Geureudong geothermal field, Landsat 8 OLI/TIRS., land surface temperature, Thermal remote sensing

<p>Foraminifera are commonly used to examine patterns of tsunami inundation occurring over centennial to millennial timescales. However, the impacts of post-depositional change on geologic reconstructions is unknown. In tropical environments, the taphonomic character (i.e. test surface condition) of a foraminifer can deteriorate, rendering them unidentifiable, and in the worst case, dissolve them entirely. Here, we investigate the rates and extent of post-depositional change associated with the foraminiferal assemblages found within the 2004 Indian Ocean Tsunami (IOT) deposit over a 15-year time interval in Aceh, Indonesia from 2007 to 2019. </p><p>The IOT deposit consisted of a 13-18cm thick, medium-fine sand unit that sharply overlays a muddy sand contact. During the 15-year time series analysis, the IOT deposit remained a consistent thickness and maintained easily recognizable stratigraphical contacts between the overlying soil layer and the underlying mud layer. The overlying soil layer increased in thickness from 2cm in 2007 to 6cm in 2019 and resulted in roots bioturbating the IOT deposit. Calcareous taxa dominated the IOT deposit assemblage, where hyaline taxa accounted for 62% of the assemblage, porcelaneous taxa for 34% of the assemblage and agglutinated taxa for 4% of the assemblage. The concentration of calcareous foraminifera within the tsunami deposit decreased by 5% from 2007 to 2019. This trend is attributable to the high abundance of delicate porcelaneous tests, which are more susceptible to post-depositional processes than the more robust hyaline tests. The taphonomic character of the foraminiferal assemblage became more corraded (dissolved, abraded and/or pitted) over the 15-year period. The relative abundance of corraded individuals within the foraminiferal assemblage increased by 4% in the IOT deposit, to reach a relative abundance of 50% by 2019 compared to 46% in 2007. Our results indicate that there is minimal change occurring within the deposit and presents good evidence that microfossils can be used as reliable indictors of tsunami origin and to identify characteristics of a tsunami deposit. While it is minimal, we recommend that post-depositional change should still be considered, especially with regards to the more delicate porcelaneous tests and over longer taphonomic timescales.</p>