Generation of meteorological tsunamis near the Balearic and Kuril Islands

Abstract. Large-amplitude sea level oscillations in the tsunami frequency range have been occasion-ally observed insome coastal zones of the World Ocean when no seismic activity was recorded. These waves are mainly related to local atmospheric disturbances and, following Defant, are going to be referred to as 'meteorological tsunamis'. As well as ordinary tsunamis, meteorological tsunamis can also be a cause of loss of life and catastrophic destruction i coastal areas. A review of such waves is presented with particular attention to the disastrous oscillations in Ciutadella inlet, the Balearic Islands, locally known as 'rissaga'. Sea level/bottom pressure measurements in the regions of the Balearic (Western Mediterranean) and Kuril (Northwest Pacific) Islands were processed together with simultaneous atmospheric pressure records in the same areas to study the nature of meteorological tsunamis. The results are used to present a descriptive and statistical analysis of strong events in these regions, to examine the response of the same inlet to different atmospheric events, and the different bay/inlets to the same event. It is found that seiches in various inlets strengthen atthe same time just when atmospheric a tivity increases, although every inlet responds to a similar atmospheric forcing with different intensity, probably due to the influence of the local topography and geometry. Three types of strong events are identified apparently responding todifferent generation mechanisms