The island of Tenerife is composed of three Miocene shields, which are centered by the Ca¿adas volcano since the Pliocene. Tenerife sits on more than 2 km thick oceanic sediments. Quaternary volcanism of the Ca¿adas series and giant landslides were principally confined to triaxial rift zones. The mechanism of triaxial rifting, however, has remained unclear. Physical analog models show that these rift zones may have formed by gravity-driven lateral escape of island segments, induced by loading of the deformable substratum. For experiments scaled to Tenerife, three adjacent sand cones were mounted onto viscous PDMS substratum. Gravitational spreading caused circumferential expansion of each cone, until a large edifice (Ca¿adas) was constructed in their center. The older cones now acted each as a buttress; radial fractures were overprinted by fractional spreading of the Ca¿adas edifice. This resulted in formation of three main extensional zones, resembling the triaxial rifting configuration of Tenerife.