After three successive eruptions, and consequent accumulations, the island emerged from the ocean as an imposing triangular pyramid crowned by a volcano more than 2,000 metres high.
The initial crevices became channels for further lava flows which grew into three mountain ridges topped by numerous volcanic cones. While the magma cooled in these channels, it solidified into gigantic vertical basalt dykes, typical of the geological architecture of El Hierro.
The volcanic activity, principally at the convergence of the three ridges, resulted in the continual expansion of the island. A mere 50,000 years ago, as a result of seismic tremors which produced massive landslides, a giant piece of the island cracked off, crashed down into the ocean and scattered along the seabed.