A possible alternative origin of Tsunamis

Tsunamis - the harbor wave- are regarded a dangerous phenomena caused by seismic events or submarine landslides - now a research by VILIBIC et al. 2010 has focused on a Tsunami that on May 7., 2007 flooded diverse Bulgarian cities on the coast of the Black Sea, but possibly was not preceded by any of these geological trigger - factors.

Fig.1. An earthquake and resulting Tsunami destroys the Italian city of Reggio Calabria in 1783 (Trustees of the British Museum, London).

The research proposes that the 4m high waves that damaged the coastal villages and cities were caused by the atmospheric circulation above the sea. According to a simulation of the Bulgarian Tsunami, on the 7. May the weather was fine, 18°C, sunshine, weak wind, but then cold air blocked warmer air and forced it to rise higher. The resulting air vortices converted energy to the surface of the sea, until the waves became swinging in tact with the air waves, the system now was enforcing itself until the waves reached a smaller bay, and the waves began to tower on each other and increment in height.

This interpretation is controversial; a former study by RANGUELOV et al. 2008 identified a possible landslide as trigger of the Bulgarian Tsunami, also if weather can trigger Tsunamis ,such phenomena should be observed on a much larger scale and higher frequency.

The new research nevertheless mentions diverse possible "Meteo-Tsunamis":

- in 1954 Chicago is invested by a wave that killed 5 people
- on 21, June 1978, the Croatian locality Vela Luka is hit by a wave
- in 1979 a wave killed some people in the Japanese city of Nagasaki
- in 2006 a wave hit's the island of Menorca causing havoc
- in 2007 and 2008 4m high waves flood localities on the Adriatic Sea

The authors propose even that the Tsunami in concordance with the eruption of the Krakatau in 1883 was not primarily caused by the collapse of the volcano, but by the explosion and resulting sound, sound is in fact a pressure wave, heard up to 5.000 kilometres and measured around the globe. This hypothesis according to the research could also explain why the water-wave, carried by the pressure-wave, reached so fast the surrounding coasts killing more than 10.000 peoples.

References:

RANGUELOV, B.; TINTI, S.; PAGNONI, G.; TONINI, R. ZANIBONI, F. & ARMIGLIATO, A. (2008): The nonseismic tsunami observed in the Bulgarian Black Sea on 7 May 2007: Was it due to a submarine landslide? GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L18613: 5 doi:10.1029/2008GL034905
VILIBIC, I.; SEPIC, J.; RANGUELOV, B.; MAHOVIC, N.S. & TINTI, S. (2010): Possible atmospheric origin of the 7 May 2007 western Black Sea shelf tsunami event. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, C07006: 12 doi:10.1029/2009JC005904