A two layer undertow model is developed which consists of surface and inner layer. The surface layer defines breaking wave dynamics and the inner layer defines the mean flow(circulation) and turbulence fields. The interface between two layers is determined by time and depth averaging of the mean water level and wave height in the surf zone (interface model), in which Reynolds stresses are taken into consideration as well as radiation stresses. The system of equations in the inner layer is derived by time averaging the mass and momentum equations over one wave period. Time and space averaging of these equations in the surface layer defines the surface boundary conditions of the mean flow field in the inner layer. Turbulence in the inner layer is discribed by the standard k−ε model.
Abstract Waves towards the shore that have a porous breakwater building will experience reflection and transmission, to determine the height of reflection and transmission wave is needed a study by the process of generating waves on the flume with a porous breakwater building, the effect of wave changes in its propagation requires an experiment in the laboratory. This study was aimed to determine the height ratio of reflection and transmission wave by using a model of pipe structure as a wave reducer by adding the friction plane of the roughness of the walls in the pipe. A method of laboratory experiment on the wave generation flume has several variations consisting of 3 periods ( T ; 1,0 seconds, T ; 1,1 seconds, T ; 1.2 seconds) and 3 water depth ( d ) are 15, 30 and 36 cm, stroke to regulate the flap motion that determines the wave height ( H ) as a wave generator that is 4, 5 and 6 by comparing the model that uses pipe wall roughness and without roughness. The result of testing indicates that the height of reflection wave ( Hr ) and transmission ( Ht ) is strongly influenced by the period ( T ). If the period increases, Hr and Ht significantly decrease, the height ratio of reflection wave using pipe wall roughness is greater than without roughness. However, it inversely proportional to the height of transmission wave ( Ht ) were a model using pipe roughness is more efficient to reduce Ht than a model without pipe roughness.
This study aims to determine earthquake vulnerable zones. We conducted research on earthquake macro-zonation based on PGA, Modified Mercalli Intensity (MMI), and type of rocks around Matano Fault in the area of 1.60 S to 2.990 S and 120.50 E to 122.470 E. We have acquired Maximum PGA and Modified Mercalli Intensity (MMI) for each observation point on the ground from the four major earthquake events. The empirical model is used due to lack of acceleration data recorded. We tried some empirical methods, but the McGuire method is found to be acceptable for this area. The result gives the maximum variation of PGA which is ranged between 18.40 - 363.54 gals. While the variation of MMI using empirical Wald attenuation gives values ranging from 2.9 - 7.7 MMI. The most vulnerable zone is located around Sorowako city with PGA value of 326.55 gals and MMI value of 7.5 MMI. This area is between ultra-basic rock and metamorphic rock formation. The vulnerable zone is near largest earthquake 6.2 M on 15-02-2011.
Abstract The sedimentation process can move slowly and continuously during sediment transportation is still ongoing from the mainland. The sediment evidence has been done by pairing the current bathymetric measurement of the previous data from the bathymetric map of the DISHIDROS of the Indonesian Navy 2011 in the confluence of the Mahakam and Karang Mumus River. Initially, the tidal measurements were carried out on 15-29 January 2019 while the bathymetry measurements were measured on 21-22 January 2019 during spring tide was over 800 m from upstream to downstream river confluences. Contour modeling measured using Software Surfer while the tidal is using the Admiralty method., to get discharge sediment performed contour coupling from both using AutoCAD software. The results of tidal analysis at the confluence of this river type Mixed Tide, Prevailing Semi Diurnal with MSL119 cm, HHWL 275 cm and LLWL-29 cm. Besides, the results of the sedimentation calculation showed an increase of 251,621.52 m 3 in the tempo of 8 years from different Years of measurement. Most of the deposits occur on the opposite side of the Karang Mumus River, and this may be due to the small current velocity of the inner side of the Mahakam River that is curved towards the Karang Mumus River. Further research should also be modeled on current patterns and numerical modeling to ensure the morphological changes of the confluence of the present river.
Micro-tremor analysis has been used on micro-zonation studies for Sorowako City area. This study is of importance since Sorowako City closes to the Matano Fault as an active seismic area. The city has been developed through mining and agriculture activities, despite prone to be vulnerable to earthquake hazards. This vulnerability increases due to heterogeneous local settlements and public facilities with non-engineering structures to support buildings design. This study aims to conduct micro-zonation over the vulnerable area from earthquake hazard covers an area of 121.3523° E – 121.3692° E and 2.5185° S – 2.5299° S. The acquisition data used portable seismograph instrument comprising of 14 observation points. The obtained signal data was then processed using gypsy software to determine the resonance factor, rock hardness level, and Kg Index. The results were formulated in three conclusions concerning vulnerability factors. The first factor is resonance phenomena. This vulnerable area caused resonances located along the Street of Merapi's settlement with a natural frequency of 0.68 Hz that resonates with seven large earthquakes of Matano Fault ranged in the interval of 0.65 – 0.82 Hz. The second factor is a cause of vulnerability which is considered to be the existence of soft rock composition with pra edominant frequency under 1 Hz that includes areas along Street of Merapi's Settlement, ship harbor, Magani Traditional Market, and bus station. The third factor is vulnerability of the areas viewed from the Kg index which gave value of greater than 30 Kg for areas of Kibait Church, Street of Merapi's Settlement, Al Ikliwan Great Mosque, and the adjacent area of Lake Matano. The latter is the result of combining frequency and amplitude of micro-tremor waves.
A mathematical model has been developed to obtain the relationship between two parameters of electrical resistivity and mechanical elasticity of subsurface rocks of the hydrothermal area of Panggo-Kaloling in Sinjai Regency.The model was developed using data exploration concerning of both methods from the area under consideration. Constructed model is able to relate a time travel of seismic waves propagation that stands for mechanical elasticity to electrical resistivity in the area. The characterictic properties of the relation show a close connection to the parameter of porosity of the subsurface rocks. Comparing the results derived from the modeling with that of obtained from measurement gives suitable approximation with error level of less than 20%. The study concludes that the model is able to predict mechanical elasticity by using geo-electric method, or electric resistivity by using seismic refraction method.
Rate of mineral deterioration in Tanjung Bunga Beach, Makassar city sediment, as a coastal city area that temporarily evolved with infrastructure development, through a Compaction test has found damage mineral from cracks, split and shatter. The aim of this research is to classify the compaction test from mineral as result texture breakage from compression test. Tanjung Bunga beach sediments based on grain size was classified from fine sand, medium sand and coarse sand. Petrographic analysis of 15 samples of in three drilling sites with 5 meters depth, found quartz mineral composition from 20 – 25%, hornblende bertween 5 – 20%, pyroxene 5 – 15%, pagioclast 5 – 15%, orthoclast 5 – 15%, biotite 10 – 20%, and opaque minerals 10 – 25%. Value of Compaction Test laboratory Fine Sand has 4 - 14.4 Div, Medium Sand has 6.7 - 20 Div, and Coarse Sand has 3.2 - 24 Div. Petrographic analysis after Mineral Compaction Test on fine sand was cracked up to 2 – 20%, split 2 – 12%, and shattered 2 – 10%, medium sand was cracked mineral up to 2 – 15%, split up to 1 – 13%, and shattered up to 1 – 5%, and coarse sand up to 1 – 10% cracked minerals, split up to 2 – 15%, and shattered up to 2 – 7%. High percentage of crack minerals were found in fine sand with low Compaction Test values and coarse sand with low crack mineral and high Compression Strength values. More cracked mineral was found in Quartz and no opaque minerals were shatter. Mineral pyroxene is founded as most shatter shape and orthoclase mineral with the most split shape.
Abstract Observations of physical oceanographic parameters including temperature and salinity were carried out in Estuary Mahakam and Karang Mumus Rivers, on July 8, 2018, and July 14, 2018, to determine the vertical distribution patterns of temperature and salinity used to identify the type of estuary confluence Mahakam and Karang Mumus Rivers. Observations were conducted at 9 points and 11 points when the neap tide and the spring tide conditions were in the estuary area to enter the Karang Mumus river at the surface, middle and bottom layers. Temperature and salinity parameters were measured using the CTD Minos sensor system equipment. X PDC-B0900 which can simultaneously record profiles of temperature and salinity parameters lowered to the bottom of the water while the point position was determined using GPS. The results of the observation of temperature distribution showed that in the Estuary between Mahakam and the Karang Mumus Rivers did not have a thermocline layer. This was because of the depth of the water under study including shallow water. Salinity distribution was obtained with a relatively homogeneous salinity towards depth water. Homogeneous salinity is an indication of a well-mixed vertical process between seawater and freshwater.
Abstract A hydrological cycle in the atmosphere plays an important role in the Earth system. [1] The hydrological cycle in the atmosphere is a source of fresh water for life on earth. Starting from the density of heavy water, it is converted into a mild vapor density which allows an increase in water vapor from the sea surface to the dew point where the process of changing water vapor into liquid phase can take place. An atmospheric machine is represented by a modified Carnot cycle below water dome containing mixed water vapor and liquid in an atmospheric layer. This study aims to learn changes in thermodynamic parameters, such as heat and work during the moist air experiencing thermodynamic processes and the correlation of temperature and humidity to rainfall. Basic information recorded by radiosonde is used as mixed water vapor and liquid parameters representing an initial atmospheric condition in producing fresh water. The results will provide information required to figure out the process of evaporation and condensation in the troposphere and the relationship between temperature and humidity to rainfall.
