Note 1 — Chapter II · EARTHQUAKES.
Reading edition
The views of Mr. R. Mallet, briefly stated, are somewhat as follows:—Owing to the secular cooling of the earth, and the consequent lateral crushing of the surface, this crushing from time to time overcomes the resistance; in which case shocks are experienced along the lines of fracture and faulting by which the crust is intersected. These shocks give rise to earthquake waves, and as the crushing of the walls of the fissure developes heat, we have here the vera causa both of volcanic eruptions and earthquake shocks—the former intensified into explosions by access of water through the fissures.—"On the Dynamics of Earthquakes," Trans. Roy. Irish Acad., vol. xxi.