MENAGE OF EARTHQUAKE

Evening Star, Issue 19410, 19 November 1926, Page 1

MENAGE OF EARTHQUAKE

EFFECT OF oUH SPOTS PRIMARY AND SECONDARY CAUSES Of all so-called destructive forces of Nature, there are probably none as devastating to life and property as those which are discussed in the science of seismology, the nature and cause of the earthquake. The most notable of these disasters which have occurred during the present century are those of April 21, 1906, which caused the destruction in San Francisco of property worth over £loo,ooojooo, loss of life to 500 persons, and injury tp body and limb of a large number of individuals; of Messina, in Italy, and Reggio, in Calabria, on December 28, 1908, when 80,000 persons perished, and immense damage was done to property; and of September 1, 1923, which also caused an appalling loss of life and destruction of property in Japan. Seismology is comparatively a modern science, dating from the year 1857, Its importance is now considered so great, that in all the leading observatories of the world part of the curriculum is devoted to it; and seismographs, or earthquake recorders, built in the ground at a depth sufficient to eliminate any chance causes of surface vibrations in the earth, are set up in such ia manner that a record of tremors or vibrations in the earth’s crust is marked by a recording pen on a revolving cylinder automatically. Two records are usually made on tho seismograph. The first is feebler than the second, and is supposed to have travelled in a straight line through the inner port of the earth: tho other has travelled by the nearest route on the earth’s suri face. From the difference in time between the two records can be deduced the distance of the disturbance and its velocity; and from the extent of the displacement of the lines marked its severity is indicated. The observatory at Melbourne has one of these machines housed in a vault at headquarters, .and at Riverview Observatory. Sydney, there is a well-equipped collection of these instruments, under the daily supervision of Father Piggot, S.J., states the Melbourne ‘ Age.’ One of the leading seismologists of his time, the late Mr John Milne, for twenty years held the position of geologist and mining engineer to the Japanese Government. His duties covered the making and study of seismological records in the “home of earthquakes.” During his sojourn in Japan, and after his return to England, ne published various volumes and contributed to scientific societies a number of papers on the science. Amongst his works was ono entitled ‘ Earthquakes,’ the sixth edition of which was revised by him in 1913, shortly before his death. In this he summarises tho result of modern inquiries. He states that many investigators chiefly attribute the phenomena to special causes and a few to general causes. He considered that they might bo attributed to very many causes, which often act in a complex manner; that among the primary causes we recognise effects due to secular loss of heat Horn ihe earth, solar* radiation, andin-."gfu\nta-* tional influences; that these may be the principal and sometimes the immediate cause of an earthquake. The secondary causes are those dependent upon tho primary causes, such as expansions and contractions of the earth’s crust, variations in temperature, barometrical pressure, rain, wind, the attractive influences of the sun and the moon in producing tides in the oceans of the earth’s crust, variations in the distribution of stress upon the earth’s surface caused by denudations and accumulations. etc. He concludes that the primary cause of earthquakes is endogenous, or produced within tho earth, and exogenous phenomena, produced outside the earth, such as gravitation of the sun and moon, and barometric fluctuations play but a small part in t the actual production of earthquakes, their greatest effect being, at theinost, to cause a slight preponderance in the number of particular seasons. In his opinion, probably 99 per cent, of the earthquakes which wo feel are due to faulting and sudden adjustments in the equilibrium of an internal fairly rigid magma. He reckoned that there is at least one earthquake daily in Japan, and probably twenty to fifty daily on the earth’s surface. QUESTION OF RIGIDITY. Cfommelin, in his work, ‘The Star World,’ cites proof's of the rigidity of the earth’s interior. He refers to one fact, discovered by Professor Chandler, that the poles of the earth oscillate in an oval curve some 60ft in length in a period of 427 days, approximately one .year and two months, the period giving a measure of the elasticity of the earth. From this Newcomb deduced that the earth must, as a whole, be more rigid than steel. Croraraelin points out that the same result has been found from a discussion of the tides; that even the solid earth has a measurable fide some inches high, and that calculations from the amount of this tide indicated the rigidity ’ of steel.

single living cell with a nucleus which will reproduce itself. FRANKENSTEIN. Mrs Shelley, the novelist, went beyond the wildest dreams of science in her creation of the monster of Frankenstein. In her story the studious scientist labors with tireless persistence night and day collecting bones, sinews, and muscles of animals and human beings and combining, uniting, and moulding them as a sculptor does his clay—until the scientist had. produced a creature counterfeiting all tho physical characteristics of a human being—but as lifeless as the sculptor’s marble. For five years he cuts loose _ completely from the society of his friends. He visits vivisection rooms and charnel houses to accumulate the human organs, sinews, and muscles with which to create his man-made man. He is profoundly dejected and disgusted with the nature of his labors, the sordid character of his materials. But. he is upheld by, the lure of his experiments, and is able to overcome his repugnance and proceed with his work until the lifeless cadaver, one night, stirs, opens his eyes, and gazes into the horrified face of his creator. Confronted by the monster ho created, Frankenstein beat his breast and screamed : CONSUMED IN FLAMES. “ Cursed be the day, abhorred devil, in which you first saw light! Cursed be the hands that formed you.” Frankenstein flees, collapses, and for weeks hovers between life and_ death in the illness brought on -by his protracted labors and the sight of his finished product. He perishes in a vain pursuit of the monster, , which * leads ‘over barren wastes to the north. When Frankenstein is dead, after months of suffering and ordeal,, his creation builds a pyre, leaps into it, andi.is consumed in the flames.

Flammarion has shown from the results of the observations by Haeckor at Potsdam from 1902 to 1905 that tie outer surface of the earth moved up ond down twice a day from Ift to 3ft. Sir George Darwin compared these movements of the earth to the breathing of an animal, the movements or tides being caused by the attraction of the moon and sun, just as ocean tides are produced by the same forces. In 1902 Sir Norman Lockyer drew attention to an apparent connection between the phenomena of sunspots and those of earthquakes. He stated: “ Because, he terrible catastrophes in Martinique and St. Vincent occurred'at a well-defined sunspot minimum, I was led to. inquire whether similar coincidences wore to be traced in the past. . . . I find it beyond question that the most disastrous volcanic eruptions and earthquakes generally occur, like the rain pulses in India, round the dates of the sun spot maxima and minima.' Tn 1867 Mauna Loa, South America. Formosa, and Vesuvius were among the regions involved; in the West Indies it was the turn of St. Thomas. The many announcements of earthquakes in the present year (1902), before the catastrophe of St. Pierre, will be in the recollection of everybody. In the maximum of 1871-72, to name only West Indian stations, Martinique first, and then St. Vincent followed suit; in, the next maximum of 1883 came Krakatoa. In Tobio. in a country where the most perfect seismological observatories exist, we find that_ at times near both sun spot maxima ."and minima the greatest number of disturbances have been recorded.” THE SUN'S ACTIVITY.

In liis work, ‘ The Astronomy of Today,’ published this year, the Abbe Moreux, director of the Observatory of Bourges, France, sums up the latest views on this phase of the matter. H« states that earthquakes take place especially at times when the sun’s activity is changing from an increasing to a decreasing process, or vice versa. He claims to Injve proved that it is at the end of the third year alter the_ maximum period of sun spots, and during the year which follows, that earthquakes occur most often and with the greatest intensity. And he asserts that it was by means of these laws that ho was enabled to predict, through the New York ‘Herald,’ the great earthquake at San Francisco - .1 those inoro recently which mine*. Messina and wasted Provence, as well as the terrible disaster of 1923, when Japan suffered so severely, and which he had predicted in the ‘Revue du Ciel* in January, 1923. _ He further states “ that an unimaginable number of particles must be ejected into space by the solar prominences, whose frequency is connected with that of sun spots. The corpuscles are the product of atomic disintegration, and so consist mainly of negatively electrified particles. On reaching the earth they impart that charge- to the Tariffed gases of the upper atmosphere; this charge, it might ho supposed, would continuously increase the potential liie of the atmospheric layer m the same sense, and to am extent to which no limit could be assigned. The’ electric charge of the atmosphere is itself a variable quantity, and it is a remarkable fact that of all the phenomena which agree most closely in, their variation _ with the periodic fluctuations of seismic activity the closest agreement is shown by a(moophcfli:'-iiicctrfoily. : Inis therefore it must he which acts .as the intermediary between the sun and our earthquakes, or which comes to,the same tiling, between the sun and the earth contractions.” He refers to the Leyden jar, and points out that ii the charge on the jar is altered its volume is also altered proportionately, and he then draws the analogy, “so in.the case of the earth the atmosphere plays the part of the tinfoil on the outside (of the jar); the crust of the earth being a had conductor, takes the place of the glass of the vessel, aaid the internal coating of the jar is very well represented by the liquid or gaseous core of the earth, which is composed of various metallic substances* If, then, the electric charge resident _in the atmosphere is by the sun’s action increased we shall have a tendency to expansion in the crust of the earth, the latteral pressures will be more pronounced. and the shell will tend to support itself instead of pressing down unon the interior mass, hence there will be a cessation of earthquakes.” This is exactly what has been found to be the case. Earthquakes are slight, or do not occui at all. in summer or in the afternoon, both of which are times when the electric charge has a high value. On the other hand, when the charge dwindles, as it does in winter or when in the latter part of the night the shell tends to contract, it is no longer independently supported, but weighs down upon the mass within: the consequemces of this is a process of settlement and collapse which involves earthquakes; It is thus not difficult to understand'that at certain times the gases enclosed within the crust try to escape in consequence of the pressure which it exerts upon them, a pressure which is itself due in part to the tendency to contract. The tension of the gases will go on increasing until the activity of the sun has reached a maximum, and in this way we have an explanation of these relations between the two sets of phenomena.

The dates of maximum and minimum sun spot periods from 1893 to date are: Maxima, 1893-1905 and 1916, the next will be'due about 1927; minima, 1901, 1911, and 1922, the next will be due about 1933. The period from maximum to maximum and that from minimum to minimum is. roughly speaking, about eleven years.