Tsunami Intensity: A Valuable Parameter of Multiple Usefulness Papadopoulos G.A., Daskalaki E., Fokaefs A. Institute of Geodynamics National Observatory of Athens, Greece

Size of a natural event is traditionally measured by the intensity that is the impact of the event Examples o Beaufort 12-point scale for wind o Saffir-Simpson 5-point scale for typhoons o Mercalli-Sieberg 12-point scale for earthquakes o EMS-98 new 12-point scale for earthquakes Intensity of natural phenomena

Modern measure of the size of a natural event is magnitude which expresses the energy of the event Examples o Richter and moment-magnitude scales for earthquakes o Newhall-Self 8-point scale for volcanic eruptions o Iida scale for tsunamis Magnitude of natural phenomena

Tsunami Scales Type of Tsunami Analogy to Earthquake Scales Intensity Scales Sieberg [1927]primitive 6-point intensity scale early intensity scales Ambraseys [1962]improved 6-point intensity scale improved intensity scales Shuto [2001]developed 6-point intensity scaledeveloped intensity scales Papadopoulos & Imamura [2001] new 12-point intensity scalenew EMS ’92 and ’98 12-point intensity scale Magnitude Scales Imamura - Iida [40’s, 50’s & 60’s] primitive magnitude scalelocal Richter magnitude scale Soloviev [1970]primitive magnitude scalelocal Richter magnitude Abe [80’s & 90’s]magnitude scalesurface-wave magnitude scale Murty - Loomis [1980]magnitude scalemoment – magnitude scale

o Size of a tsunami based on the macroscopic observation of tsunami’s effect on humans, objects, including various size of marine vessels and buildings o What factors control the disastrous effects of the tsunami? - humans, - effects on objects (e.g. vessels of variable size), - nature (e.g. ground erosion), - damage to buildings. Tsunami intensity

o Incorporates twelve divisions o Is consistent with several 12-grade seismic intensity scales. (Papadopoulos & Imamura, 2001) a.Independent from physical parameters b.Sensitive to the small difference in tsunami effects c.Detailed description of each division by taking into account all possible tsunami impacts on human and natural environment 12-point tsunami intensity scale

Empirical correlation between the intensity K, introduced by Papadopoulos & Imamura (2001) and the quantities H and i introduced in formula by Shuto (1993) KH (m) i I-V<1.00 VI2.01 VII-VIII4.02 IX-X8.03 XI16.04 XII32.05

The 12-point scale has been used in: o Indian Ocean after the tsunami of 2004 (Narayan J.P. et al., Pure & Applied Geophysics, 163, 1279p., 2006; Rossetto T. et al., Natural Hazards, 2006; Maheshwari et al., Earthquake Spectra, 23/III, S475p.; Chang et al., Earthquake Spectra, 23/III, S863p.) o Black Sea (Yalciner A. et al., J. Geophys. Res., 109, C12023p., 2004) o Mediterranean Sea (Tinti, S. et al., Marine Geology, 225, 311p., 2006) o Azores Islands (Andrade C, J. Volcanol. & Geoth. Res., 156, 172p., 2006) o Australia (Dominey-Howes, D., Marine Geology, 239, 99p., 2007) o Indonesia (Lavinge et al., Nat. Hazards Earth Syst. Sci., 177p., 7, 2007) o Portugal (Baptista et al., NHESS, 2009)

Further Presentation of the 12-scale can be found in the following books: o Β. Levin & Μ. Nosov: Physics of Tsunamis & Kindred Phenomena in Ocean, Moscow, Janus-K, 2005; Physics of Tsunamis, Springer, o Tsunami Glossary from the Intergovernmental Oceanographic Commission of UNESCO and the International Tsunami Information Centre, USA, 20p, o M. Woods & Μ.B. Woods: Tsunamis, Lerner Publ. Comp., Minneapolis, o E. Guidoboni & J.E. Ebel: Earthquakes & Tsunamis in the Past: A guide to techniques in historical seismology, 2009.

Possible applications of the new 12-point tsunami intensity scale o Revision of tsunami catalogues o Mapping the geographical distribution of the impact of past tsunamis o Description of the tsunami impact by intensity isolines o Construction of empirical attenuation laws of the tsunami impact o Tsunami statistics

Observation points: 206 Indian Ocean 2004 Intensities

Observation points: 53 Indian Ocean 2004 Intensities

Observation points: 149 Indian Ocean 2004 Intensities

Tsunamicity of Greece: Tsunamicity of Greece: the highest in the Euro-Mediterranean region Papadopoulos & Fokaefs, 2005

9 July 1956 earthquake M=7.5 tsunami: 15-20m

The tsunami source 9 th July 1956 event

VI-VIII

V IV III

Wave attenuation of 9 th July 1956 Attenuation law /epicentral distances 3 largest intensities K per 50km / epicentral distances

↘Magnitude-frequency or G-R relation (Gutenberg and Richter, 1944) extensively used in seismology to describe the exponential decrease of the event frequency, N c, with the increase of the event magnitude, M: Earthquake Statistics

o Intensity-frequency → equivalent to the magnitude-frequency or G-R relation (Gutenberg & Richter, 1944) used in seismology: o Describes the exponential degree of the event frequency with the decrease of the event size o Excluding frequencies of events with K ≥ 3: Application of the tsunami statistics: West Hellenic Arc

From it comes out that the mean repeat time, T K, of events of intensity equal to or larger than K is: or the mean yearly rate of occurrence is KT k =10 bK-a r =1/T k last event t (years)K max maximum intensity, K max, which is the most probable to be observed within time interval t is given by the expression

Poissonian Statistics o From the mean yearly rate of tsunami occurrence we calculated the probability,, to observe at least one tsunami of intensity K equal to or larger than a given value within particular time interval, t. o The probability to observe x events in t years is while the probability to observe at least one tsunami event in t years is t (years)K≥2K≥4K≥6K≥8K≥

Seismic damage: e.g. Bucharest, 4 March, 1997, M= 7.4 SAFER Project, EU-FP6, 2009, Partner NIEP, Romania intensity mapshake map

Possible future application for tsunamis o Construction of expected tsunami damage maps in terms of tsunami intensity in analogy to expected seismic damage o This requires: - inundation zone from numerical simulation - Vulnerability analysis - Damage scenario

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