Alqinthara Nuraghnia’s research while affiliated with Institut Teknologi Telkom and other places

A tsunami can cause significant economic losses for tourism areas like Batukaras Village, which is located on the southern coast of Java Island. This paper seeks to elaborate on the calculation of economic losses in tourism areas due to damage to buildings, loss of land production, and loss of income, based on high-resolution geospatial data. The data are derived from UAV photogrammetry surveys and high-resolution tsunami run-up models. The tsunami worst-case scenario run-off model provides an inundation area of 43 ha with 185 buildings and 24.4 ha of productive land. The estimated losses from the tsunami disaster amounted to IDR 208.79 billion, consisting of 49.63 billion from building damage, 6.73 billion from productive land, and 152.43 billion from the tourism sector. These results show that the tsunami disaster will severely affect tourism areas, because the tourism sector makes up 73% of the total economic losses. Reductions in the amount of economic loss, in addition to spatial planning near the coastline to reduce the number of impacted buildings and productive land, can be achieved by accelerating the recovery period so that economic activities after the tsunami disaster can be carried out immediately, including in the tourism sector.

Indonesia's location in the middle of tectonic plates makes it vulnerable to earthquakes and tsunamis, especially in the megathrust zone around the island of Sumatra and the southern part of the island of Java. Research shows a seismic gap in southern Java, which poses a potential threat of megathrust earthquakes and tsunamis, impacting coastal areas such as Batukaras in West Java, a popular tourist destination. To prepare for disasters, probabilistic tsunami hazard analysis (PTHA), which focuses on seismic factors, was carried out by modelling tsunamis on 3348 sub-segments of 4 large megathrust segments in the south of Java. Stochastic earthquake modelling was used to simulate the occurrence of a tsunami from an earthquake with Mw 6.5 to the highest potential magnitude. This research shows that the PTHA in Batukaras reveals varying heights of 0.84, 1.63, 2.97, and 5.7 m for each earthquake return period of 250, 500, 1000, and 2500 years, respectively. The dominant threat arises from the West Java–Central Java megathrust segment, emphasising the importance of preparedness, although the annual probability of tsunamis is generally low. Our study will deepen knowledge of tsunami hazards associated with megathrust activities near Batukaras for mitigation planning and decision-making, and it can become a reference for similar coastal tourist areas.

A tsunami disaster can cause significant economic losses for a tourism area like Batukaras Village, which is located on the southern coast of Java Island. This paper tries to elaborate on the calculation of economic losses in tourism areas due to the damage to buildings, loss of land production and loss of income based on high-resolution geospatial data. The data are derived from UAV photogrammetry surveys and high-resolution tsunami run-up models. The tsunami worst-case scenario run-off model provides an inundation area of 43 ha with 185 buildings and 24.4 ha of productive land. The estimated losses from the tsunami disaster amounted to IDR 208.79 billion, consisting of 49.63 billion from building damage, 6.73 billion from productive land and 152.43 billion from the tourism sector. This result shows that the tsunami disaster will severely affect tourism areas because the tourism sector contributes 73% of the total economic losses. Reduction of the economic loss, in addition to spatial planning near the coastline to reduce the number of impacted buildings and productive land, can be achieved by accelerating the recovery period so that economic activities after the tsunami disaster can be carried out immediately, including in the tourism sector.

Pasang surut (pasut) merupakan fenomena periodik naik turunnya air laut yang berpengaruh besar terhadap seluruh aktifitas manusia di wilayah pesisir dan laut. Tulisan ini menganalisis variasi spasial dari karakteristik pasut yang terjadi di Laut Jawa. Karakteristik pasut tersebut dipetakan dari empat komponen pasut utama (K1, O1, M2 dan S2) dari model pasut global TPXO9v5 dan diverifikasi menggunakan 14 stasiun pasut dari Badan Informasi Geospasial. Hasil verifikasi menunjukkan kesesuaian yang baik antara data model dengan data pengukuran dengan rata-rata nilai RMS 0,8 – 2,2 cm untuk komponen pasut dan 7,6 cm untuk tunggang pasut, sementara tingkat kesesuaian untuk tipe pasut adalah 93%. Nilai amplitudo komponen pasut pada kelompok harian (K1 dan O1) memiliki nilai lebih besar sekitar dua kali lipat dibandingkan dengan kelompok harian ganda (S2 dan M2). Sementara untuk nilai fase, hanya gelombang O1 yang penjalarannya ke arah timur, sementara gelombang lainnya menjalar ke arah barat. Secara spasial, tunggang pasut di Laut Jawa bervariasi dari 0,3 m di bagian tengah pada bujur 108-110° BT dan bertambah tinggi ke arah barat dan timur sampai 1 m. Pengetahuan mengenai variasi spasial karakteristik pasut ini penting dalam mempelajari pola pasut, bidang referensi ketinggian atau kedalaman, atau untuk kerekayasaan seperti manajemen pelabuhan dan instalasi infrastruktur lepas pantai. Tides are a periodic rising and falling sea level phenomenon that significantly impact all human activities in coastal and maritime regions. This paper discusses the spatial variations of tidal characteristics tides in the Java Sea. The characteristics are mapped from four main tidal components (K1, O1, M2, and S2) extracted from the TPXO9v5 tide model and verified by 14 tidal stations. The verifications show a good agreement between the model data and measurements, with an average root mean square (RMS) of 0.8 - 2.2 cm for tidal components and 7.6 cm for tidal range, and the conformity level for tidal types is 93%. The amplitude of the diurnal tidal components (K1 and O1) is approximately twice that of the semi-diurnal tidal components (S2 and M2). Regarding the phase, only the O1 wave propagates eastward, while the other waves propagate westward. Spatially, the tidal range in the Java Sea varies from 0.3 m in the central part at longitudes 108-110° E, increasing in height as it moves westward and eastward to reach 1 m. Information on the spatial variations in tide characteristics is crucial for studying tidal patterns, tidal datum, and engineering purposes like port management and offshore infrastructure.

Indonesia's location in the middle of tectonic plates makes it vulnerable to earthquakes and tsunamis, especially in the megathrust zone around Sumatra Island and the southern part of Java Island. Research shows a seismic gap in southern Java, which poses a potential threat of megathrust earthquakes and tsunamis, impacting coastal areas such as Batukaras Village in West Java, a popular tourist destination. To prepare for disasters, Probabilistic Tsunami Hazard Analysis (PTHA), which focuses on seismic factors, was carried out by modeling tsunamis on 3,348 sub-segments of 4 large megathrust segments in the south of Java Island. Stochastic earthquake modeling to simulate the occurrence of a tsunami from an earthquake with 6.5 Mw to the highest potential magnitude on each segment. This research shows that PTHA in Batukaras Village reveals varying heights of 0.84 m, 1.63 m, 2.97 m, and 5.7 m for each earthquake return period of 250 years, 500 years, 1000 years, and 2500 years. The dominant threat arises from the West Java-Central Java megathrust segment, emphasizing the importance of preparedness, although the annual probability of tsunamis is generally low. Our study will deepen knowledge of tsunami hazards associated with megathrust activities near Batukaras Village for mitigation planning and decision-making, and it can become a reference for similar coastal tourist areas.