Tsunami focusing and leading wave height

Field observations from tsunami events show that sometimes the maximum tsunami amplitude might not occur for the first wave, such as the maximum wave from the 2011 Japan tsunami reaching to Papeete, Tahiti as a fourth wave 72 min later after the first wave. This might mislead local authorities and give a wrong sense of security to the public. Recently, Okal and Synolakis (2016, Geophys. J. Int. 204, 719-735) discussed "the factors contributing to the sequencing of tsunami waves in the far field." They consider two different generation mechanisms through an axial symmetric source -circular plug; one, Le Mehaute and Wang's (1995, World Scientific, 367 pp.) formalism where irritational wave propagation is formulated in the framework of investigating tsunamis generated by underwater explosions and two, Hammack's formulation (1972, Ph.D. Dissertation, Calif. Inst. Tech., 261 pp., Pasadena) which introduces deformation at the ocean bottom and does not represent an immediate deformation of the ocean surface, i.e. time dependent ocean surface deformation. They identify the critical distance for transition from the first wave being largest to the second wave being largest. To verify sequencing for a finite length source, Okal and Synolakis (2016) is then used NOAA's validated and verified real time forecasting numerical model MOST (Titov and Synolakis, 1998, J. Waterw. Port Coast. Ocean Eng., 124, 157-171) through Synolakis et al. (2008, Pure Appl. Geophys. 165, 2197-2228). As a reference, they used the parameters of the 1 April 2014 Iquique, Chile earthquake over real bathymetry, variants of this source (small, big, wide, thin, and long) over a flat bathymetry, and 2010 Chile and 211 Japan tsunamis over both real and flat bathymetries to explore the influence of the fault parameters on sequencing. They identified that sequencing more influenced by the source width rather than the length. We extend Okal and Synolakis (2016)'s analysis to an initial N-wave form (Tadepalli and Synolakis, 1994, Proc. R. Soc. A: Math. Phys. Eng. Sci., 445, 99-112) with a finite crest length, which is most common tsunami initial waveform. We fit earthquake initial waveform calculated through Okada (1985, Bull. Seismol. Soc. Am. 75, 1135-1040) to the N-wave form presented by Tadepalli and Synolakis (1994). First, we investigate focusing phenomena as presented by Kanoglu et al. (2013, Proc. R. Soc. A: Math. Phys. Eng. Sci., 469, 20130015) and compare our results with their non-dispersive and dispersive linear analytical solutions. We confirm focusing phenomena, which amplify the wave height in the leading depression side. We then study sequencing of an N-wave profile with a finite crest length. Our preliminary results show that sequencing is more pronounced on the leading depression side. We perform parametric study to understand sequencing in terms of N-wave, hence earthquake, parameters. We then discuss the results both in terms of tsunami focusing and leading wave amplitude. Acknowledgment: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe).
European Geosciences Union General Assembly 2016 (17 - 22 Nisan 2016)


Long waves generation by atmospheric pressure disturbances and case study
Çabuk, Özge; Yalçıner, Ahmet Cevdet; Department of Civil Engineering (2019)
One of the interesting marine events is the long wave generation due to spatial and temporal changes of atmospheric pressure and wind fields during storm events. These kind of phenomena is called as storm surge and cause basin wide and local water level changes in sea surface and sometimes amplifies at some regions. There are examples of these kinds of event in all over the world. In this study the atmospheric pressure and wind fields are used as the input to the numerical model NAMI DANCE which solves Nonl...
Tsunami Hazard Assessment on the Egyptian Coast of the Mediterranean
Zaytsev, A. I.; Babeyko, A. Yu.; Kurkin, A. A.; Yalçıner, Ahmet Cevdet; Pelinovsky, E. N. (Pleiades Publishing Ltd, 2019-09-01)
Tsunami forecast possibilities for areas with a small base of historical tsunamis have been discussed using the Probabilistic Tsunami Hazard Assessment (PTHA) method, which is based on a statistical analysis of a sufficiently large number of real and predictive earthquakes with a subsequent calculation of possible tsunami waves. This method has been used for a long-term tsunami hazard assessment on the Mediterranean coast of Egypt. The predicted wave heights have been shown to vary along the coastline due t...
Earthquake generation cycles and tsunami simulations providing possible scenarios for Turkey Marmara sea and Japan Nankai trough and Japan trench
Horı, Takane; Yalçıner, Ahmet Cevdet; Meral Özel, Nurcan; Kılıç, İrfan; Miyazaki, Shinichi; Hyodo, Mamoru (null; 2015-04-12)
In order to obtain comprehensive earthquake and tsunami scenarios for disaster assessment, numerical simulations of earthquake generation cycles and resultant tsunami generations have been performed in Japan. The occurrence of the 2011 Tohoku earthquake has realized us the necessity to consider all the possible scenarios without preconceptions. We have performed large-scale numerical simulations using Earth Simulator and K-computer for earthquake generation cycles along the Nankai trough, southwest Japan, w...
Tsunami early warning in the eastern Mediterranean, Aegean and black sea
Ozel, Nurcan Meral; Necmioglu, Ocal; Yalçıner, Ahmet Cevdet; Kalafat, Dogan; Yilmazer, Mehmet; Comoglu, Mustafa; Sanli, Ugur; Gurbuz, Cemil; Erdik, Mustafa (2012-09-17)
A National Tsunami Warning Centre in Turkey (NTWC-TR) established at the Kandilli Observatory and Earthquake Research Institute (KOERI) under the ICG/NEAMTWS (The Intergovernmental Coordination Group for the Tsunami Warning System in the Northeastern Atlantic, the Mediterranean and connected seas region) initiative is operational since January 2012 based on MOD1 Tsunami Scenario Database and TAT (Tsunami Analysis Tool) received from EC-JRC through a collaborative agreement. NTWC-TR is also acknowledged as a...
Tsunamis bridging science engineering and society
Kanoğlu, Utku; Bernard, Eddıe; Synolakıs, Costas (null; 2015-06-22)
There have been significant advances in tsunami science since the devastating 2004 Boxing Day tsunami. Yet, the 2011 Japan tsunami dramatically demonstrated that tsunamis continue to avoidably take lives and cause significant damage. Broadcasted live to a stunned world audience, the trail of destruction in 2011 in probably most tsunami ready nation underscores the difficulties of implementing practical advances in hazard mitigation. The Philosophical Transactions A theme issue entitled ‘Tsunamis: Bridging ...
Citation Formats
U. Kanoğlu, “Tsunami focusing and leading wave height,” presented at the European Geosciences Union General Assembly 2016 (17 - 22 Nisan 2016), Vienna, Austria, 2016, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/77955.