Читать книгу A Study of Recent Earthquakes - Charles Davison - Страница 6

I propose in this book to describe a few of the more important earthquakes that have occurred during the last half century. In judging of importance, the standard which I have adopted is not that of intensity only, but rather of the scientific value of the results that have been achieved by the study of the shocks. Even with this reservation, the number of earthquakes that might be included is considerable; and I have therefore selected those which seem to illustrate best the different methods of investigation employed by seismologists, or which are of special interest owing to the unusual character of their phenomena or to the light cast by them on the nature and origin of earthquakes in general.

Thus, the Neapolitan earthquake possesses interest from a historical point of view; it is the first earthquake in the study of which modern scientific methods were employed. The Ischian earthquakes are described as examples of those connected with volcanic action; the Andalusian earthquake is chiefly remarkable for the recognition of the unfelt earth-waves; that of Charleston for the detection of the double epicentre and the calculation of the velocity with which the vibrations travelled. In the Riviera earthquake are combined the principal features of the last two shocks with several phenomena of miscellaneous interest, especially those connected with its submarine foci. The Japanese earthquake is distinguished from others by its extraordinary fault-scarp and the very numerous shocks that followed it. The Hereford earthquake is a typical example of a twin earthquake, and provided many observations on the sound phenomena; while the Inverness earthquakes are important on account of their connection with the growth of a well-known fault. The great Indian earthquake owns few, if any, rivals within historical times, whether we consider the intensity of the disturbance or the diversity and interest of the phenomena displayed by it—the widespread changes in the earth's crust, both superficial and deep-seated, and the tracking of the unfelt pulsations completely round the globe.