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.

A new multibeam dataset of Nieuwerkerk and Emperor of China (NEC) seamounts was acquired during the Jalacitra 2-2022 ”Banda” Expedition in the Banda Sea region. This study discusses a morphometric analysis of the seamounts based on a high-resolution bathymetry digital elevation model (DEM) and describes the morphometric features, namely: slope, profile curvature, and aspect. Morphological results indicate that the Nieuwerkerk seamount has an area of 2,416 km2 with a maximum peak elevation of approximately 3,460 m above the seabed and 357 m below the water surface. In the southwest of the Nieuwerkerk seamount, two new seamounts were discovered, which are still unnamed and seem morphologically connected to the Nieuwerkerk seamount. Each of the seamounts covers an area of 148 km2 and 220 km2, respectively, with a maximum peak elevation of approximately 2,338 m and 2,053 m above the seabed. Additionally, both seamounts have an elevation of 1,878 m and 2,017 m below the sea surface. Meanwhile, the Emperor of China seamount is located southwest of the three formerly mentioned seamounts, with the maximum peak seats at 2,165 m below the sea surface. Seamount C is located in the west of the surveyed area and it covers an area of 95.6 km2 with an elevation of 1,834 m above the seabed. The results of regression analysis indicate that all of the features could be used for the morphological classification.