Darwin’s Reports on Catastrophic Natural Phenomena and Modern Science: Seaquake-Induced Waves, Atomization and Cavitation

Abstract

Darwin reported that … From the great wave not immediately following the earthquake, but sometimes after the interval of even half-an-hour, …it appears that the wave first rises in the offing; and as this is of general occurrence, the cause must be general. I suspect we must look to the line where the less disturbed waters of the deep ocean join the water nearer the coast, which has partaken of the movements of the land, as the place where the great wave is first generated. It would also appear that the wave is larger or smaller, according to the extent of shoal water which has been agitated together with the bottom on which it rested…(Darwin, Journal of researches into the natural history and geology of the countries visited during the voyage of H.M.S. Beagle around the world, under the command of Captain Fitz Roy, R.N. T. Nelson and Sons, London, 1890, p. 374). These words, and also the material given in the Chap. 3 show that Darwin had described the formation and the coastal dynamics of ocean waves caused by the earthquake. Obviously, he was the first who had given a qualitative, but scientific, analysis of this phenomenon, and had emphasized the complex character of the coastal development of tsunamis. Describing results of the earthquake Darwin wrote also … two explosions, one like a column of smoke, and another like the blowing of a great whale, were seen in the bay of Concepcion. The water also appeared every where to be boiling; and it ‘became black, and exhaled a most disagreeable sulphureous smell’. … The two great explosions in the first case must no doubt be connected with deep-seated changes; but the bubbling water, its black colour and fetid smell, the usual concomitants of a severe earthquake, may, I think, be attributed to the disturbance of mud containing organic matter in decay … (Darwin, Journal of researches into the geology and natural history of the various countries visited by H.M.S. Beagle, under the command of Captain FitzRoy, R.N. from 1832 to 1836. Henry Colburn, London, 1839, р. 374). Thus, Darwin had described the behaviour of the shallow sea and the bottom mud during a seaquake. The explosions are results of the passing up of large cavitation zones (bubbles) through the sea/atmosphere surface. These zones were formed because of vertical oscillations of the sea bed. Surface waves and the boiling may be also explained by the seaquake. Apparently, bubbles and surface waves may also appear in the mud because of the underwater earthquake.