Extreme wave height analysis using Weibull and Rayleigh distribution in some coastal areas affected by tsunami disasters and earthquakes in September 2018 at Central Sulawesi

Abstract One of the most important measures is the availability of data and information through research related to the analysis of extreme wave heights at each location to be built. This study aims to provide methods and information in determining extreme wave heights that have been required to be known when designing coastal structures and public infrastructure on the coast. In this study, the extreme wave height was calculated based on a wave model simulation with an incident wave scenario that has an extreme wave height at each research location. The results showed that the distribution of extreme wave height in the waters of Palu Bay, the coast of Banawa District, was closer to the Rayleigh distribution, while the waters of Sirenja District, Donggala Regency were more in accordance with the Weybull distribution. This difference is caused by the attenuation factor of wave height due to differences in coastal morphology. The attenuation value of wave height at Banawa beach reaches 53 - 78%, while in Sirenja District it is only 35 - 46% compared to the extreme wave height in the deep sea.</jats:p

Identification of distribution changes of leachate in a landfill

Abstract The distribution of leachate in the Kawatuna landfill, Palu City, which is still implementing the Open Damping system, has been researched in 2011 where it was detected up to a depth of 7 meters and led to reservoir of leachate. The Landfill Control system has been implemented, but the leachate pipe was not functioning, and part of the storage pool was damaged during the earthquake on September 28, 2018, so that leachate is scattered everywhere. This study aims to determine changes in the distribution of leachate used geoelectric-resistivity method with Wenner-Schlumberger configuration. Data were collected at 3 points within the landfill site and 1 point outside the location, with a length of 48 meters each and processed using EarthImager 2D software. From the research results, it is obtained that the resistivity value of leachate is 1–9.7 ohmmeter. Based on the cross-sectional resistivity analysis, leachate was spread to a depth of 9.7 m, which indicates an increase depth of 2.7 m and the distribution direction was not leading to reservoirs of leachate</jats:p

Modeling of tidal current and residual currents patterns in Tomori Bay, North Morowali Regency, Central Sulawesi Province

Abstract Research has been carried out to model current patterns and residual current in Tomori Bay using Mohid Studio 2016. The model using a finite volume approach with a tidal model driven by the results of Geospatial Information Agency (BIG) predictions placed on the open boundary of the model. The modeling results are compared with the measurement results in Tomori Bay. The tidal current velocity in the high tide conditions increases the current velocity at the bay neck and weakens after passing Tokobae Island. The current velocity on the west side of Tokobae island is higher than that of the east of Tokobae. At the mouth of the bay, the current velocity on the north side is higher than at the south side of the bay mouth. The tidal current velocity is higher than the residual current with a maximum tidal current velocity of 25.3 cms−1 and a maximum velocity of residual current 12.6 cms−1. The residual current that describes the fate of pollutants while in the Tomori Bay waters. The residual flow pattern shows a vortex on the north side of the bay mouth and to the southeast of Tokobae Island.</jats:p

Analysis of seasonal variability of wave height in Makassar Strait

Abstract This study was conducted to examine spatially the seasonal variability of sea wave characteristics in the Makassar Strait waters by utilizing the third generation wave model, MIKE 21 Spectral Wave Model. The study was conducted by observing seasonal variability of sea wave height in Makassar Strait waters for 10 years. The data used are wind data predicted by ECMWF every 6 hours during the period 2006 - 2015 as the main input of wave energy generation. The domain model is adjusted to the wind configuration in a uniform grid size of 5’ x 5’ which is considered to be sufficient to represent the bathymetry of the Makassar Strait waters with location limits of 1,00 0LU - 3,98 0LS and 116,15 0BT - 120,30 0BT and 15 stations. Based on the results of the study, showed that high waves occur in the west season which tends to follow the monsoonal pattern according to the local climate type. The maximum significant wave height tends to occur in the western, central and southern waters of the Makassar Strait with an average observed in the middle of the year in the June, July and August periods (east monsoon). For the study of coastal waters, maximum wave height fluctuations tend to be uniform.</jats:p

Design and implementation of an Arduino-based instrument for parabolic motion

Abstract The lack of a physical instrument for determining the initial speed of experiment of the parabolic motion in the Department of Physics, Tadulako University, is one problem. In this research, we have been designed, implemented, and tested to show the initial velocity value of an Arduino-based to address this problem. The stages of this research began with the design and manufacture of mechanical systems, electronic systems such as power supply circuits and infrared detector circuits, motor stepper circuit, a series of servo motors, LCD circuits, and keypad circuits using the Arduino ATmega 2560 microcontroller. The next stage is making the test program and the main program. This tool has been tested and operated so that it gets good results. The initial measured speed is displayed on the LCD. The stability of measuring objects is excellent based on a low standard deviation between 0.02 - 0.06.</jats:p

Identification of potential liquefaction in Kabonena

Abstract The research was conducted in Kabonena village, which aims to see the subsurface structure and the liquefaction potential. The research was conducted using the geoelectric resistivity method with the Wenner system. The parameters used are geological data, hydrogeology and formation values to obtain between the resistivity value and the lithology of the study area. Furthermore, by considering the geological, hydrogeological conditions and formation factor values, the specific resistance values for each layer are interpreted. The results obtained show that the layers with specific resistance values of 39.16 - 97.9 Ωm are dominated by water-saturated sand/gravel. The resistivity value above 97.9 - 200 Ωm is the layer of molasses and alluvium deposits/coastal deposits, and the resistance value above 200 Ωm is the layer of crushed granite and granodiorite. The existence of a subsurface structure like this, so that in Kelurahan Kabonena it is called a liquefaction event. The location has a layer of saturated air that points to the east with a depth of less than 24 meters.</jats:p

Study of ocean wave characteristics in Lembasada, Donggala District, Central Sulawesi

Abstract This study discusses the characteristics of ocean waves in Lembasada waters, Banawa Selatan, Donggala District, Central Sulawesi. The characteristics of ocean waves are related to significant wave height and peak period. This study was conducted by utilizing the reanalysis data from ECMWF 1996, 2008, 2015 and bathymetry data from Seamap. The analysis is done by observing seasonal variability in the presence of ENSO and ordinary effects. Based on the results obtained, indicating that in the normal year without any ENSO influence, the wave height in these waters is likely to follow a seasonal pattern, with significant wave height lower than the ENSO effect.</jats:p