Andrey Zaytsev

A new GIS-based tsunami risk evaluation: MeTHuVA (METU tsunami human vulnerability assessment) at Yenikapı, Istanbul

Istanbul is a mega city with various coastal utilities located on the northern coast of the Sea of Marmara. At Yenikapı, there are critical vulnerable coastal utilities, structures, and active metropolitan life. Fishery ports, commercial ports, small craft harbors, passenger terminals of intercity maritime transportation, waterfront commercial and/or recreational structures with residential/commercial areas and public utility areas are some examples of coastal utilization that are vulnerable to marine disasters. Therefore, the tsunami risk in the Yenikapı region is an important issue for Istanbul. In this study, a new methodology for tsunami vulnerability assessment for areas susceptible to tsunami is proposed, in which the Yenikapı region is chosen as a case study. Available datasets from the Istanbul Metropolitan Municipality and Turkish Navy are used as inputs for high-resolution GIS-based multi-criteria decision analysis (MCDA) evaluation of tsunami risk in Yenikapı. Bathymetry and topography database is used for high-resolution tsunami numerical modeling where the tsunami hazard, in terms of coastal inundation, is deterministically computed using the NAMI DANCE numerical code, considering earthquake worst case scenarios. In order to define the tsunami human vulnerability of the region, two different aspects, vulnerability at location and evacuation resilience maps were created using the analytical hierarchical process (AHP) method of MCDA. A vulnerability at location map is composed of metropolitan use, geology, elevation, and distance from shoreline layers, whereas an evacuation resilience map is formed by slope, distance within flat areas, distance to buildings, and distance to road networks layers. The tsunami risk map is then computed by the proposed new relationship which uses flow depth maps, vulnerability at location maps, and evacuation resilience maps.

Development of a Tsunami Inundation Map in Detecting Tsunami Risk in Gulf of Fethiye, Turkey

NAMIDANCE tsunami simulation and visualization tool is used to create tsunami inundation maps showing quantitative maximum tsunami flow depths in Fethiye. The risk of an extreme, but likely earthquake-generated tsunami is estimated at Fethiye Bay for 14 probabilistic earthquake scenarios. The bay is located 36°39′5″N 29°7′23″E, southwestern Turkey, which has coastline to the eastern Mediterranean Sea. The tsunami simulation and inundation assessment are performed in three stages: (1) formation of a digital elevation model of the region from the best available topography/bathymetry dataset, (2) estimation of a maximum credible tsunami scenario for the region and determination of related earthquake parameters, (3) high resolution tsunami simulation and computation of near shore and overland tsunami dynamics in the study area using tsunami simulation and visualization code NAMIDANCE, (4) determination of spatial distributions of tsunami characteristics (maximum water elevations, water velocities, flow depths) under the critical tsunami condition. The results are based on the most recent descriptions of potential tsunami sources, topographic and bathymetric databases, and tsunami numerical models. We present an innovative study concentrating on preparation of quantitative flow depths and inundation maps with a very high-resolution bathymetry/topographic dataset in the eastern Mediterranean. Inundation maps will be used to analyze the effects of possible tsunamis. The presented research is crucial to raising the awareness of government officials, the public, and other stake holders about the high probability of a tsunami event in Turkey. Moreover, the results of this study will help to plan for evacuation routes, establish safe zones, and assist in preparation for the tsunami, creating public awareness, and planning evacuation routes before the actual tsunami event happens.

The possibility of tsunami in the Sea of Okhotsk caused by deep-focus earthquakes

The earthquake that occurred on May 24, 2013, in the basin of the Sea of Okhotsk with a magnitude of 8.3 was the strongest in this region. We have modeled a possible tsunami caused by such an earthquake. The simulations confirm that the wave heights were sufficiently small because the earthquake epicenter depth was 640 km. We analyze the oscillations of the DART buoys in the vicinity of the earthquake source and show that they were not associated with the tsunami waves. Analysis of the available pressure gauge records at different points of the Sea of Okhotsk show that only in one case (Iturup Island) can the observed oscillations of the sea level with a height of approximately 4 cm be classified as tsunami waves.

Wave amplification and resonance in enclosed basins; a case study in haydarpasa port of Istanbul

The amplification of waves inside the ports becomes critical under extreme events (storms or tsunamis) by causing unexpected amplification and damage in the ports. The resiliency of harbors and coastal utilities against marine hazards is important for the post disaster recovery operations. Resonance oscillations and resultant wave amplifications inside the basins are other important adverse effects which cause damage on structures and interruption of harbor functions. Those are necessary for the post event recovery operations. One of the important utilities located in Istanbul coast near Marmara is the port of Haydarpasa where regular shaped basins were designed inside the harbor. The resonance oscillations, periods of free oscillations and flow pattern of long waves in Haydarpasa port under the actions of long waves are investigated using numerical model (NAMI DANCE). An initial impulse is inputted, and a simulation is performed. The time histories of water surface fluctuations are computed at several numerical gauge points inside the harbor. The spectral analysis by using Fast Fourier Transform technique is applied to the records of all numerical gauge points and respective spectrum curves are obtained. The peaks of spectrum curves of each numerical gauge location are also determined. The peaks of spectrum curves coincide with the resonance frequencies. The computed frequencies are discussed by comparing with the frequency of the waves which occur in the Marmara Sea in regard to their possible amplification and effects to Haydarpasa port.

The Moneron Tsunami of September 5, 1971, and Its Manifestation on the Sakhalin Island Coast: Numerical Simulation Results

Observation data on the September 5, 1971, earthquake that occurred near the Moneron Island (Sakhalin) have been analyzed and a numerical simulation of the tsunami induced by this earthquake is conducted. The tsunami source identified in this study indicates that the observational data are in good agreement with the results of calculations performed on the basis of shallow-water equations.

EFFECT OF TSUNAMI PARAMETERS ON THE SEDIMENTATION

Tsunami induced flows expose the morphological changes at the coastal zone. The morphological changes due to tsunami motion could be categorized to sediment transportation and hence erosion, deposition, scouring. The recent devastating tsunamis in 2004 and 2011 have not only caused extensive damage on marine structures but also cause morphological changes especially in the sand coastal plains, river mouths and their surroundings. The sediment transports by storm wave have been studied extensively but the problem of tsunami and morphology still need further investigations. However, it is remained a developing field of study yet since the validation methods for real cases are complicated. In order to achieve a better validation, the data for both topography and bathymetry are necessary before and after the hazard. The distribution of morphological changes due to tsunamis can be governed by topography, tsunami current and the characteristics of ground material. Rouse number is one of the indicator to describe the initiation of sediment motion. Therefore the transport modes of the sediment can be observed by following the change of the Rouse number. In this paper the spatial and temporal change of Rouse number in the study domain during a tsunami is investigated. As the case study the tsunami inundation and morphological changes near Antalya region in Mediterranean Sea at south of Turkey due to a critical tsunami scenario is studied. The spatial and temporal changes of Rouse number is computed by the tsunami simulation and the possible movement of the ground materials are determined and discussed.

Understanding the Possible Effects of Near and Far Field Tsunamis on Lesser Antilles by Numerical Modeling

Results of the numerical modeling of potential tsunamis generated in the center of the Caribbean Sea are given. Numerical modeling is performed with the use of TUNAMI N3 and NAMI DANCE. The maximum amplitude of the wa- ter elevation in Lesser Antilles can reach upto 3-4m. The travel time of tsunami is 1.5 hours to Northern islands of Lesser Antilles and 2 hours to Southern islands of Lesser Antilles. It must also be noted that the southern coast of Caribbean Sea will be much more effected comparing to the Lesser Antilles when a tsunami is generated in the center of the Caribbean Sea.