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Coasts are continually changing and remote sensing from satellites has the potential to both map and monitor coastal change at multiple scales. Unlike optical technology, synthetic aperture radar (SAR) is uninfluenced by darkness, clouds, and rain, potentially offering a higher revision period to map shoreline position and change, but this can only be feasible if we have a better interpretation of what shorelines as extracted from SAR imagery represent on the ground. This study aims to assess the application of shorelines extracted from SAR from publicly available satellite imagery to map and capture intra-annual to inter-annual shoreline variability. This is assessed in three tidally controlled coastal study areas that represent sand and gravel beaches with different backshore environments: low-lying dunes and marsh; steep, rocky cliff; and urban environments. We have found that SAR shorelines consistently corresponded to positions above the high-water mark across all three sites. We further discuss the influence of the scene geometry, meteorological and oceanographic conditions, and backshore environment and provide a conceptual interpretation of SAR-derived shorelines. In a low-lying coastal setting, the annual change rate derived through SAR presents a high degree of alignment with the known reference values. The present study contributes to our understanding of the poorly known aspect of using shorelines derived from publicly available SAR satellite missions. It outlines a quantitative approach to automatically assess their quality with a new automatic detection method that is transferable to shoreline evolution assessments worldwide. [ABSTRACT FROM AUTHOR]

Advances in the understanding of tsunami impacts allow developing products to assess its consequences in tsunami-prone areas, as it is the case of the coast of the Sultanate of Oman. This paper presents the followed methodology and the obtained results for the assessment of the tsunami hazard of the coast of Oman and the development of the scenario database that feeds its Tsunami Warning System (TWS). Initially, a seismo-tectonic analysis of the area was carried out, focused on identifying the seismic areas whose earthquakes could generate tsunamis affecting the coast of Oman. A database of 3181 tsunamigenic sources was characterized by means of the parameters that define their focal mechanisms. This database includes scenarios with magnitudes Mw ranging from 6.5 to 9.25 within the study area, but it is especially focused on the Makran Subduction Zone (MSZ). The 3181 cases were numerically propagated to feed the database and to work as precomputed scenarios for the TWS: In case of tsunami, the results for the closest precomputed scenario (in location and magnitude) are shown. From the database, 7 worst-case scenarios were selected and computationally simulated at national and local scale, in 9 municipalities all along the coast of Oman, resulting in tsunami hazard maps containing relevant variables in the flooded area, such as the inundation water depth and the drag level (hazard degree for people instability). Finally, in order to manage conveniently the results, an online tool, called Multi-Hazard Risk Assessment System (MHRAS), was developed. This tool is a viewer that contains an easy-to-use application, including the results of the tsunami hazard assessment and the tsunami scenario database, and the selection algorithm to choose the proper case among the precomputed ones. The results of this research are part of the National Multi-Hazard Early Warning System of Oman (NMHEWS). [ABSTRACT FROM AUTHOR]

Oman is located in an area of high seismicity, facing the Makran Subduction Zone, which is the major source of earthquakes in the eastern border of the Arabian plate. These earthquakes, as evidenced by several past events, may trigger a tsunami event. The aim of this work is to minimize the consequences that tsunami events may cause in coastal communities by integrating tsunami risk assessment and risk reduction measures as part of the risk-management preparedness strategy. An integrated risk assessment approach and the analysis of site-specific conditions permitted to propose target-oriented risk reduction measures. The process included a participatory approach, involving a panel of local and international experts. One of the main concerns of this work was to obtain a really useful outcome for the actual improvement of tsunami risk management in Oman. This goal was achieved through the development of comprehensive and functional management tools such as the Tsunami Hazard, Vulnerability and Risk Atlas and the Risk Reduction Measures Handbook, which will help to design and plan a roadmap towards risk reduction. [ABSTRACT FROM AUTHOR]