Predicting Earthquakes.

New Zealand Graphic, Volume XLVIII, Issue 17, 23 October 1912, Page 58

Predicting Earthquakes.

Tliat excessive terror naturally produced by ithe shaking and sundering of the solid earth and the attendant downfall and ruin of substantial edifices has been increased a thousand-fold in earthquake zones by the apparent impossibility of foreseeing seismic disturbances long enough beforehand to take even elementary precautions against fatalities. A trained geo-physicist, M. Kocveslighety, lias Jong been working on this problem, and announces hisi belief that he has now partially solved it. lie considers that the primal cause of the earthquake is not external factor whether cosmic or meteorological. Sucli factors at most merely precipitate the shock, which is actually due to excessive tension alt some point. The essential thing, therefore, is to learn where such tension exists, and this he considers by no means impossible. The speed of propagation of seismic waves vwries according to the elasticity of the strata traversed, and this elustivity itself depends on the ten, sion. Consequently if this speed be measured at repeated times between two given points, it will be seen whether the tension varies. If this tension shows a tendency to increase, seismic shocks aro to be feared. In other words, the elastic.ty will reach a critical degree where a 'breaking of the strain may be occasioned by some exterior disturbance. In short the ease is analogous to that of an explosion produced by a spark in gunpowder. Hence it would be well in regions subject to seismic disturbances to take frequent measurements of the speed of earthwaves and estimate the corresponding variation in elasticity. Thus a probable rupture of tension might be predicted and even the time of its occurrence estimated. The method was tested w’tb favourable results in the vicinity of Wokio during the period from 1895 t> 1898. Further testing by exact observations on a large scale are advisable in such regions as Sicily, Calabria, and California, since the theory is quite logical, but needs empirical attestation to be generally aeeeptedi