Baruna Jaya Research Articles

Characterization of Underwater Landslides in Krui Waters, Lampung-Indonesia using Shallow Seismic and Sonar Data

Abstract Krui Waters, Lampung, Indonesia, is an area that has the potential for a tsunami disaster. Local tsunamis can be caused by underwater landslides owing to ground movement and gravitational forces. Imaging underwater conditions using sonar and shallow seismic systems is an interesting research topic for geological disaster researchers. Underwater landslides are very important for disaster mitigation, especially for tsunami prediction. This research aims to identify the characteristics of underwater landslides around Krui Waters, Lampung, Indonesia, using imaging analysis methods from sonar data and a sub-bottom profiler (SBP). The underwater landslide phenomenon in this area is still not known in detail, and therefore requires further research. All data were obtained from the results of hydrographic, geological, and geophysical surveys of RV Baruna Jaya IV in 2020. The sonar data shows surface characteristics such as the presence of Furrows (Gravel Waves), Cobble (Boulder), as well as Canyons and landslides or mass movements rocks. SBP data show the characteristics of the seabed in the form of a canyon with a slope greater than 160. Finally, the morphological characteristics and features obtained could possibly be a potential source of local tsunamis owing to the high slope.

Ichthyoplankton Biodiversity in the Indonesian Fisheries Management Area-573 in 2015

Abstract Studying ichthyoplankton is crucial for understanding the impact of fish larvae mortality on the recruitment of adult fish and fishing resources. Fish larvae samples were collected in the southern waters of Java using the Baruna Jaya IV research vessel in September - October 2015. Fish larvae were collected using bongo-net and oceanographic data were collected using Conductivity Temperature Depth (CTD) are Temperature and salinity and chlorophyll-a using Aqua MODIS satellite L3 at 36 stations. The results showed the range of fish larvae abundance was 0 - 2,074 ind/1000 m3 with an average of 174 ind/1000 m3. The fish eggs were found with an abundance of 0 - 1,601 eggs/1000 m3. and an average of 213 eggs/1000 m3. The composition of fish larvae recorded 22 families, there were 5 dominant families namely Scombridae (28.60%), Bregmacerotidae (22.96%), Carangidae (7.93%), Blennidae (7.52%), and Gobiidae (7.52%). The diversity of fish larvae was most prevalent at station 28 (SST 26.7 0C; SSS 34.4 PSU; and CHL-a 0.43 mg/m3) and station 36 (SST 27.4 0C; SSS 34.4 PSU) each found 9 families. The abundance of fish larvae was mostly found at stasion 11 had SST 23.50 0C; SSS 34.56 PSU; and CHL-a 0.33 mg/m3 with the dominance of the family Bregmacerotidae. Scombridae was mostly found at stasion 22 with sea surface temperature (SST) 26.52 0C; sea surface salinity (SSS) 34.28 PSU; and sea surface chlorophyll-a (CHL-a) 0.41 mg/m3 which is in the southern waters of Lombok.

Exploring tsunami generation and propagation: A case study of the 2018 Palu earthquake and tsunami

The tsunami disaster in Palu, Indonesia, on September 28, 2018, caused many casualties and damage along Palu Bay, Indonesia. Prior to the tsunami, an earthquake was recorded 25 km northeast of Donggala. The analysis suggests that the tsunami was triggered by a landslide beneath the waters of Palu Bay. The investigation then focused on the earthquake's impact on the tsunami. This study conducts simulations to discern the dominant causes of tsunamis, comparing the effects of landslides with earthquakes. Three distinct tsunami sources were identified: earthquake-only (T-E), earthquake and submarine landslide (T-EL), and submarine landslide-only (T-L). Interpretation of tsunami source parameters for underwater landslides is carried out accurately. A nesting grid numerical method was employed to increase resolution and accuracy in the simulations. This study accurately interprets tsunami source parameters using data from the Bathymetry National Data-Geospatial Information Agency (185 m resolution) and the field survey data from Baruna Jaya IV-BPPT Research Vessel Indonesia (25 m resolution), thereby contributing to the creation of a tsunami inundation model map. This map serves to inform preparedness efforts and guide recommendations for infrastructure development in the Palu Bay area. The tsunami inundation model map is verified with field data and estimated using tide gauge monitoring data. The characteristics of the tsunami waves on September 28, 2018, reflect a T-EL-type tsunami source, while the T-L type source produces tsunami waves with longer periods compared to earthquake-generated tsunamis (T-EL). The T-E type, located on land, had minimal influence in causing the tsunami, despite the destructive potential of the shallow-depth M7.5 earthquake.

Transformation of South Pacific Water Masses in the Halmahera Sea

The Halmahera Sea is part of the eastern entry route of the Indonesian throughflow (ITF) passages. The characteristics and transformation of the South Pacific water masses are presented based on the HYCOM model (Hybrid Coordinate Ocean Model) and direct observations of CTD (Conductivity, Temperature, Depth) acquired during the East Indonesian Expedition in October 2017 using RV Baruna Jaya VIII. This study is aimed at characterizing the typical water masses observed in the Halmahera Sea and tracking the transformation of the South Pacific water masses in the region. The results show that there was an indication of strong vertical mixing of maximum salinity of the South Pacific thermocline water masses, i.e., South Pacific Subtropical Water (SPSW), from ~35.2 PSU at isopycnal 24 – 25 kg m-3 becomes ~34.8 PSU in the Southern Halmahera Strait (around 200 km from the entry passage, the Northern Halmahera Strait), and rapidly decreases from the Southern Halmahera Strait and Obi Strait to become 34.6 PSU in the Maluku Sea. These preliminary findings suggest a strong mixing in the southern Halmahera Strait and Obi Strait.

Water masses stratification and circulation in the southern part of Banggai Upwelling Region in Maluku Sea

Banggai Waters is in the western Maluku Sea, where the secondary pathway of Indonesian Throughflow passes and seasonal coastal upwelling takes place in this region, providing a high marine productivity and potential fishing ground. This study aims to describe water mass stratification and circulation using CTD casts and SADCP section datasets from the BUDEE cruise in September 2022 onboard RV Baruna Jaya VIII. The results show that mixed layer depth varies between 43-112 m with a mean temperature of 25.82(± 0.88) ºC. North Pacific water origin (NPSW and NPIW) is present in this southern section. The depth of chlorophyll maximum is much shallower in the upwelling center. Furthermore, for the first time, we identified a strong northward flow from the Bote Strait, disrupting Banggai upwelling water with cooler and fresher Banda water. Estimates of northward transport volume through this strait is about 0.531 Sv.

Multitemporal Acoustic Backscatter Data Analysis to Monitor the Dynamics of Seabed Surface Sediments

Backscatter strength is a product of underwater acoustic remote sensing. This study used a multibeam echosounder as an acoustic remote sensing instrument to collect backscatter strength data. These data are then used to classify the surficial sediment distribution. To monitor the difference in seabed sediment distribution, a time-series survey was performed to obtain multitemporal acoustic backscatter data. An EM 304 multibeam system from Kongsberg was mounted on the Research Vessel Baruna Jaya III from the Indonesia National Research and Innovation Agency (BRIN). It was used to collect backscatter data in the waters of Raja Ampat, Indonesia. The data were collected at different times, April and July 2021. Geometric and radiometric corrections were applied to these backscatter data. Based on the angular response curve analysis from acoustic backscatter strength, the research area can be classified into four seabed sediment types: boulder, gravel, sand, and mud. A comparison of both time series backscatter data shows that the boulder and gravel areas increased by 13.6% and 19.0%, respectively. Elsewhere, the area with sediment types of sand and mud diminished by 30.5% and 2.0%. The change in the sediment type area occurred as much as 50.5%, while the remaining 49.5% area remained unchanged. This resulting value is apparently derived from the steep topography that rapidly changes sediment distribution. One such suggestion is that sediment sampling should be performed to confirm the model from angular response curve analysis.

Multitemporal Acoustic Backscatter Data Analysis to Monitor the Dynamics of Seabed Surface Sediments

Backscatter strength is a product of underwater acoustic remote sensing. This study used a multibeam echosounder as an acoustic remote sensing instrument to collect backscatter strength data. These data are then used to classify the surficial sediment distribution. To monitor the difference in seabed sediment distribution, a time-series survey was performed to obtain multitemporal acoustic backscatter data. An EM 304 multibeam system from Kongsberg was mounted on the Research Vessel Baruna Jaya III from the Indonesia National Research and Innovation Agency (BRIN). It was used to collect backscatter data in the waters of Raja Ampat, Indonesia. The data were collected at different times, April and July 2021. Geometric and radiometric corrections were applied to these backscatter data. Based on the angular response curve analysis from acoustic backscatter strength, the research area can be classified into four seabed sediment types: boulder, gravel, sand, and mud. A comparison of both time series backscatter data shows that the boulder and gravel areas increased by 13.6% and 19.0%, respectively. Elsewhere, the area with sediment types of sand and mud diminished by 30.5% and 2.0%. The change in the sediment type area occurred as much as 50.5%, while the remaining 49.5% area remained unchanged. This resulting value is apparently derived from the steep topography that rapidly changes sediment distribution. One such suggestion is that sediment sampling should be performed to confirm the model from angular response curve analysis.

Vertical Mixing in The Onshore Region of The Northwestern Maluku Sea, Indonesia

Spatio-temporal dynamics of vertical mixing in the northwestern Maluku Sea were quantified using the Thorpe Method from archived CTD datasets collected during the expedition of Baruna Jaya VIII RCO-LIPI on November 12–13, 2000. The turbulent kinetic energy (TKE) dissipation rate and vertical eddy diffusivity values inspected the variability of mixing properties. Higher values for both parameters were found at the shallower bathymetry, which is less than 1000 m deep. This suggests that the water column is vertically unstable as a result of being often subjected to internal solitary wave (ISW) breaking events. The strong temporal variability observed from the density profile also indicated a strong impact on internal tide activity. There was temporal fluctuation of the TKE dissipation rate as well as vertical eddy diffusivity values following semidiurnal periodicity, with typical variability up to one order of magnitude for both the dissipation and diffusivity. The range of fluctuation is [6.8×10-8 ? 9.3×10-7] W kg-1 and [1.5×10-5 – 5.4×10-3] m2s-1, respectively in the upper 200 m depth. This water generated a high dissipation rate and vertical diffusivity when regularly exposed to internal solitary waves breaking from the Lifamatola Passage.Keywords: mixing properties, CTD data, turbulent kinetic energy, vertical eddy diffusivity

Corrosion Rate Analysis and Prediction of the Remaining Life of the Research Vessel to Improve Ship Safety Aspects

<p>Corrosion is a major concern in the marine industry, compromising the safety and integrity of ships. This paper presents a corrosion rate analysis and prediction of the remaining life of the Baruna Jaya IV research vessel using non-destructive testing (NDT) ultrasonic testing to improve ship safety aspects. The NDT ultrasonic testing was conducted on the ship's hull to evaluate the thickness and detect any hidden corrosion. The results were used to develop a corrosion rate model and predict the remaining life of the ship using a probabilistic model. The study found that the corrosion rate of the ship was high, and the remaining life of the ship was estimated to be less than five years. The study’s findings can be used to develop a maintenance and repair strategy to reduce corrosion and improve the safety of the Baruna Jaya IV research vessel.</p>

Developed Methodology for Ship Retrofitting (Case Study: RV Baruna Jaya I)

Developed Methodology for Ship Retrofitting (Case Study: RV Baruna Jaya I)

Spatial distribution of carbon dioxide (CO2) fluxes in the Sunda Strait and west of Sumatra waters

Carbon dioxide (CO2) is one of the main global warming gases which cause global climate changes, droughts, forest fires, sea level rise, and flooding. Natural CO2 sinks are the mainland, oceans, and atmosphere. Indonesian waters have the potential to absorb CO2 due to their high primary productivity. This study aimed to understand the variability of CO2 in order to determine whether Indonesian waters act as carbon sources or carbon sinks and fill the CO2 data gaps. The field survey was conducted at the Sunda Strait and west Sumatra waters during February–April 2010, using RV Baruna Jaya III. The Sunda Strait has a role as a carbon source, whereas the west of Sumatra waters as carbon sinks. The partial pressure of CO2 is more influenced by the pH. The average net flux of CO2 in the Sunda strait was 841.603 mol CO2cm−2day−1, which shows the release of CO2 from the ocean into the atmosphere occurs in this region. On the other hand, the average net flux of CO2 in the west of Sumatra was -945.292 mol CO2cm−2day−1, which shows the absorption of CO2 by the ocean occurs in the region.

Prioritization of Research Vessel Lubricating Oil System Equipment for Maintenance Purpose Using Failure Mode Effect and Criticality Analysis (FMECA) Method. Study Case: RV. Baruna Jaya

Prioritization of Research Vessel Lubricating Oil System Equipment for Maintenance Purpose Using Failure Mode Effect and Criticality Analysis (FMECA) Method. Study Case: RV. Baruna Jaya

The estimation of total vertical uncertainty from multibeam echosounder during MeGaMal Expedition seafloor mapping for earthquake mechanism at Maluku Sea.

In 2022, the Indonesian government initiated the EWIN MeGaMal expedition (Ekspedisi Widya Nusantara Mekanisme Gempa Laut Maluku). The goal of the expedition is to map earthquake and tsunamigenic potential areas around Ambon Island. The expedition was carried out from 8 to 28 August 2022 using RV Baruna Jaya VIII. One of the methods used in the expedition is the multibeam echosounder (MBES) survey. To obtain an accurate bathymetry result, several stages need to be carried out. Initially, a vessel reference frame (VRF) with a defined reference point called common reference point (CRP) needs to be established. Then, sensor offsets in 3D (three-dimensional) is measured with respect to CRP. The next stage is to calibrate and validate the vessel’s differential global navigation satellite system (D-GNSS) and Heading system statically. Afterwards, a patch test dynamic MBES calibration is performed. Finally, the accuracy of the bathymetry result is analyzed in accordance with the International Hydrographic Organization (IHO) SP 44. This paper is aimed to describe each of the above methodologies and present the preliminary result. Results show that the Patch Test calibration has values of roll: -0.19°, pitch: -5.40°, and yaw: 1.09°. It is expected this expedition could contribute for mitigation of earthquakes and tsunamis in Eastern Indonesia.

Seabed morphology characterization for Indonesian cable-based tsunameter route in Cilacap Segment, Indonesia

The Indonesian government has initiated a program for Ina Tsunami Early Warning System by the development of sea level monitoring systems including a Cable-Based Tsunameter. Seabed feature characterization is a critical part of the engineering design process as well as for the understanding of environmental impacts. This study aims to characterize the seabed morphology along the cable route plan at the Cilacap segment by analyzing the seafloor mapping and identifying of any existing hazards. A series of marine surveys for the data acquisition hydro-acoustic and geophysics was conducted by RV Baruna Jaya IV, in December 2020. The analysis and interpretation of seabed geomorphology were conducted using qualitative methods on four Blocks. Results indicate anthropogenic objects (debris, wreck, and scars), while the features of ripples, and pockmarks. Furthermore, sediment layers which are interpreted into four units from the top to bottom shows fine grained sediment towards the top. Finally, the hazard assessment denotes that there are three hazard categories (low, medium, and high), of which the highest category is located in the pockmark cluster (Block 4). The existing CBT cable route place is faced with geomorphological obstacles and environmental threats, so it’s recommended to change the route as far as 50meters.

The offshore Foraminifera of the Togean Islands, Tomini Gulf; distribution and ecological significance

The hydrological complexity, the gulf shape, and the undeveloped geological setting of the Togean Islands in the middle of the waters assembled the area to be such an interesting place to discover its ecological uniqueness. Foraminifera was widely used as proxies for various ecological aspects. Real time and retrospective studies of the vertical and horizontal distribution of foraminiferal communities on such waters are the reflection of many ecological factors in the area. The purpose of the Foraminiferal research on the offshore Togean Islands is to discover the ecological roles that directly and indirectly affect the characteristics of the vertical and horizontal distribution. The study was also referring various ecological aspects from previous studies at the research site. Sampling was carried out in September 2015 using the Baruna Jaya VIII RV in the Togean Islands waters, Tomini Gulf, through a gravity core. Foraminifera analysis was carried out at four core samples from the adjacent waters of four reef islands; Una-una, Pengempang, Togean, and Kalla at 5 m to 455 m water depths. Core samples of various lengths, from 8 cm to 34 cm were dominated by planktonic foraminifera. The dominance of planktonic taxa in reef waters indicates a robust oceanic influence to the reef islands. Upwelling events in several locations in the region as well as volcanic processes that are ongoing also play a role in the distribution of the bulk of planktonic taxa in the reef waters of Togean Islands.

Design of Real-Time Monitoring System for Performance Parameter and Alarm of Main Engine RV. Baruna Jaya III

With the increasing age of RV. Baruna Jaya III (30 years), the ships often face various problems. The continuous operation of the engine causes a decrease in its performance which eventually results in the failure of the main engine. For instance, damage to the main engine can stop operating of the ship at sea which eventually have various impacts on ship and life safety as well as operational cost. In this context, efforts to manage ships especially for the operation of main engine and its prevention from errors through real time monitoring and control system have become a major issue. This study aims to design a monitoring and alarm system for the main engine performance on the RV. Baruna Jaya III as the preliminary step for the development of the overall monitoring system. As a result, a design for data acquisition of the main engine performance parameters in real time and the design of a ship’s main engine failure alarm system have been developed using PLC-based design technology and a SCADA-based monitoring system. This system can be thus further built for the performance of the ship’s main engine, as part of management ship operations and maintenance policies.

Fish larvae spatial distribution and composition in FMA 711

The South China Sea is the western part of Sunda Shelf, divided into shallow water in the southern part and deeper in the north. The Indonesian Fishery Management Area (FMA) 711, located in the southern part of this area inside the country’s territorial waters, was one of fertile and high in biodiversity in terms of fish species. The collection of fish larvae was conducted as part of biological parameters on a stock assessment cruise survey in October 2017 using the Baruna Jaya IV research vessel. Results showed that there were 47 families of fish larvae found in 31 sampling stations. Abundance ranges from 16,2 – 2342,2 ind/1000 m3 with an average of 413.6 ind/1000 m3. The number of Families varies in every station from 2 – 22 with an average of 11. The dominant taxon was Engraulidae with 21.47%; followed by Nemipteridae, Scaridae, and Pomacentridae with 11,55%, 7,72%, and 7,34% respectively. Family with the highest distribution was Nemipteridae and Pomacentridae which cover 80,65 % of the sampling area. Others that also have high coverage are Carangidae, Scaridae, and Labridae with 64,52 %, 61,29 %, and 58,06 % respectively. This result indicates the high biodiversity of the area.

Design and finite element analysis of gondola construction for multibeam echosounder (MBES) installation on RV Baruna Jaya III - BPPT

The revitalization of hydrographic equipment at the Research Vessel (RV) Baruna Jaya III has been carried out by the Technology Center for Marine Survey (BTSK) – BPPT to improve its service capabilities. A Multi-Beam Echosounder (MBES) for the deep-sea mapping up to 8000 meters depth has been chosen to replace the existing equipment which only has a mapping capability of 3000 meters depth. MBES requires a support construction mounted on the vessel hulls as its housing, considering the installation principle from both the shipowner and MBES maker. In this research, a gondola installation principle has been agreed to develop. The gondola construction has been designed in consideration of actual vessel conditions and several requirements by the MBES maker. The design construction is further analyzed using the finite element method (FEM) to ensure its strength and safety and meet Indonesian Classification Society (BKI) minimum requirements. The analysis conditions are divided into 3; hydrostatic load (A), sensors load (B), and the combination of hydrostatic and sensor load (C). The von Mises stress was obtained from finite element analysis for conditions A, B, and C, respectively, 164 MPa, 1.552 MPa, and 160.8 MPa. The analysis results in all loading conditions have met the minimum allowable stress required by Indonesia Classification Society rules, which is 180 MPa. In conclusion, the design of the gondola construction for MBES installation on RV Baruna Jaya III has good structural strength and safety, so it is feasible to use.

Percampuran vertikal di Perairan Laut Maluku dan Talaud pada bulan Februari 2021

<strong>Vertical mixing in the northern Maluku Sea and Talaud Waters in February 2021. </strong>The spatial variability of water mass mixing in the northern Maluku Sea and Talaud waters are presented based on the results of Eastern Indonesia Expedition (EIT) 2021 using RV Baruna Jaya VIII-LIPI. The turbulent kinetic energy dissipation rate was obtained using the Kunze-Williams-Briscoe (KWB) Method calculated from CTD (Conductivity, Temperature, Depth) and LADCP (Lowered Acoustic Doppler Current Profiler) datasets. We found the dissipation rate in the core layer of North Pacific Subtropical Water (NPSW) and North Pacific Intermediate Water (NPIW) are in the order of 10<sup>-6</sup> W/kg and 10<sup>-8</sup> W/kg, respectively. The KWB Method used in this study is also proven comparable with the Thorpe Method.

Indirect estimation of turbulent mixing in western route of Indonesian throughflow

The Indonesian Throughflow (ITF) via its western path conveys mainly North Pacific water origin with Smax thermocline water and Smin intermediate water from its entry portal in Sangihe-Talaud arcs to the main outflow straits in Lombok, Ombai and Timor passage. Along its route, the throughflow water characteristics transforms significantly due to strong diapycnal mixing forced by internal tidal waves interaction along complex topography such as passages, sill, straits, and shallow islands chains. This paper reports a brief estimate of turbulent mixing profiles in Sangihe chains, and Makassar Strait. The CTD dataset are obtained from the year of maritime continent (YMC) Cruise in August 2019 on board the R.V. Baruna Jaya I. The Thorpe method is used to analysis dissipation energy ( ε ) and vertical diffusivity (Kz ) from CTD dataset. It is shown that the highest ε epsilon 5.87 × 10−7 Wkg −1 and Kz 4.42 × 10−3 m2s 1 are found in the Sangihe area. In Labani Channel and Dewakang Sill the averaged vertical diffusivity is much weaker at the order of 10−4 m 2s1. Thus, Sangihe Chains station have the highest values compared to other stations at depth 950-1000 meters.