The identification system for illegal, unreported, and unregulated (IUU) fishing and transshipment of incidents is one effort as early warning and it can be adopted by the Indonesian ministry of fisheries and marine affairs. The system has been developed using several methods. One of them is the artificial neural networks (ANN) have been used, but it is several weaknesses when AIS data is lost. The system able to identify in missing data in a short duration of time only. The development of a system for IUU identification proposed using a fuzzy logic system (FLS). The IUU identification system consists of subsystems: (i) missing data prediction, (ii) anomaly trajectory decision, (iii) IUU selection, and (iv) IUU decision. The performance of FLS is compared between fuzzy type 1 and type 2. The system tested using data of IUU occurrences waters in high frequency. Both SLF type 1 and type 2 are able to give result in very good accuracy for IUU fishing and transshipment identification.

Sumatra is one of the most seismically active regions in the world due to the oblique convergence between the Indo-Australian and Eurasian plates, where strain is partitioned between the Sunda megathrust and the Great Sumatran Fault (GSF). While most seismicity in North Sumatra occurs along mapped strands of the GSF, several damaging earthquakes have occurred outside known fault zones, raising critical questions about hidden seismogenic structures. This study investigates the seismotectonic framework of the Karo region, with a focus on the 2017 Karo earthquake (Mw 5.6), using the double-difference relocation method. A dataset of local earthquakes recorded by the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) was analyzed to refine hypocenter locations, reduce uncertainties, and identify seismic clusters. Relocation results significantly improved spatial resolution, reducing average location errors to less than 3 km, and revealed clustered seismicity along a northwest–southeast trending structure offset from the Renun Fault. Depth cross-sections indicate brittle faulting within the upper crust (5–12 km), and the aftershock alignment suggests the presence of an unmapped subsidiary fault accommodating dextral shear. Comparisons with similar studies across Sumatra and Java confirm that off-fault seismicity is a common but often overlooked contributor to regional hazard. These findings underscore the importance of integrating relocated seismicity into national hazard models to account for hidden faults. By providing improved fault geometry and seismotectonic insights, this study enhances the understanding of earthquake sources in North Sumatra and supports future efforts in seismic hazard mitigation and disaster risk reduction in one of Indonesia’s most vulnerable regions.

Ternate waters of North Maluku is one of Indonesian eastern waters whose maritime weather is often unpredictable. Weathers prediction is important to avoid accidents in the waters. The aim of this research is to obtain a predictor model of wave’s height and current’s speed suitable for the Ternate waters using Takagi-Sugeno fuzzy logic. The data used is data from BMKG Maritime of Bitung which recorded per 6 hours during 5 years from July 2010 – June 2015. In order to reach accuracy of > 85%, 3 model predictor’s that used waves height and current speed are predictor Model A, Model B and Model C. Each model uses different input and total membership function. The result of this research shows that the Model C is the best model for Ternate waters. Model C uses 4 membership functions for 3 input variables. Inputs of waves height predictor consist of the actual wind speed (U(t)), actual waves height (H(t)) and waves height 6 hours ago (H(t-6)) and accuracy percentage of waves height 6 hours ahead (H(t+6)) is 91,99%; while inputs of current speed predictor consist of actual wind speed (U(t)), actual current speed (Cu(t)) and current speed 6 hours ago (Cu(t-6)) and accuracy percentage of current speed 6 hours ahead (Cu(t+6)) is 81,63%.