Thanks to the global news networks and their educational style of presentation there must be few who need an explication of the workings of the tectonic plaques which make up the earth's crust. In the same way it should not be necessary to give detailed explanations of the fact that the fault lines where these plates meet and exert tremendous forces are where the molten mass of the earth's core breaks out as volcanoes. Neither is it arcane knowledge that this same pressure along fault lines causes one plate to slide up over another or both to push upwards against each other, so forming hills and mountains. Should this process occur upon the sea-bed the tip of the mountain will appear above water as an island. Often both volcanic and upward pressure forcing occur together in the formation of such islands. Until recently the volcanic folding, which is particularly visible along the Santa Eulalia cliffs opposite the island of 'Tagomago' right along to the beach of Cala San Vicente, was ignored or explained away as conglomerate stratus forced into the undulating forms by lateral pressure when pushed up from ancient sea-beds in a malleable state. However, in the last decade a survey for the laying of a gas pipeline from the peninsular to Ibiza upset the academic status quo by revealing a large dormant volcano only 40 kilometers from the coast of San Antonio.
Another folkloric myth that could often be hear cited as scientific fact some thirty to forty years ago when the author arrived in Ibiza was that the Balearic islands were an extension of the Pyrenees mountain chain, including the myth of certain springs as arriving along the rock stratification's from these high mountains in the manner of subterranean aqueducts. The need to know just what is below a city and more so in the planning of a new one, gave rise to national surveys to discover just where the fault lines lay. The new science sprang from the destruction of San Francisco and the realization that it was built upon the vast system of fractures collectively known as the San Andres fault. In Spain such research in the 1970s revealed the extent of the Guadalquivir fault system, which is now known to run from just below Cadiz to the coast of Alicante and on into the sea embracing the Balearic islands. The cause of the mild earthquakes felt on the island every few years. Here the African plate meets the European and the elevation of our island is, therefore, part of the slow and vast process which gave rise to the Alps of southern Europe. However, the island building process did not occur in one dramatic geological incident. Rather, fossils in the various stratum which constructed the island indicate that no less than seven upheavals have occurred during the geological ages from the Triassic to the Miocene, with the islands only becoming separate entities during the Pliocene, each event piling another sedimentary layer upon the last. Moreover, all of these layers have been fractured and tilted by later earthquakes and volcanic activity so that the island resembles a seven layer cake that has been jumped upon and kicked from side to side. It is therefore vital to know these seemingly boring facts when contemplating building or drilling for water. The fact that a neighbor dug down to an even strata of hard calcite rock (the grey 'roca viva' or limestone) upon which to lay the foundations of his house in no way implies that this happy accident continues to the spot some three hundred meters away where you intend to build, even though the surface is now flattened by erosion. Sonic surveys and boreholes are vital on this island before buying building land in isolated spots. Previously to such services becoming available in the last twenty years it was all a matter of dousing and asking the areas eldest inhabitants of past disasters. One prime example being the fact that the church near the cliffs of 'Es Cubells' was built half upon a solid rock strata and half upon the loose clay and rock amalgam of the cliffs. The inevitable occurred and it cracked in half as it settled, now being propped up by massive and ugly buttresses. The fact that speculators were then recently allowed to build mansions upon these fragmented cliffs is another story to be explored later. Geological history may be a dry matter, but to ignore it is to find that the very wet matter of your having built your house at the end of a funnel valley where 'a once in a hundred year flood' explodes onto the plain! See Ibizaholidays.com for more history.
Another folkloric myth that could often be hear cited as scientific fact some thirty to forty years ago when the author arrived in Ibiza was that the Balearic islands were an extension of the Pyrenees mountain chain, including the myth of certain springs as arriving along the rock stratification's from these high mountains in the manner of subterranean aqueducts. The need to know just what is below a city and more so in the planning of a new one, gave rise to national surveys to discover just where the fault lines lay. The new science sprang from the destruction of San Francisco and the realization that it was built upon the vast system of fractures collectively known as the San Andres fault. In Spain such research in the 1970s revealed the extent of the Guadalquivir fault system, which is now known to run from just below Cadiz to the coast of Alicante and on into the sea embracing the Balearic islands. The cause of the mild earthquakes felt on the island every few years. Here the African plate meets the European and the elevation of our island is, therefore, part of the slow and vast process which gave rise to the Alps of southern Europe. However, the island building process did not occur in one dramatic geological incident. Rather, fossils in the various stratum which constructed the island indicate that no less than seven upheavals have occurred during the geological ages from the Triassic to the Miocene, with the islands only becoming separate entities during the Pliocene, each event piling another sedimentary layer upon the last. Moreover, all of these layers have been fractured and tilted by later earthquakes and volcanic activity so that the island resembles a seven layer cake that has been jumped upon and kicked from side to side. It is therefore vital to know these seemingly boring facts when contemplating building or drilling for water. The fact that a neighbor dug down to an even strata of hard calcite rock (the grey 'roca viva' or limestone) upon which to lay the foundations of his house in no way implies that this happy accident continues to the spot some three hundred meters away where you intend to build, even though the surface is now flattened by erosion. Sonic surveys and boreholes are vital on this island before buying building land in isolated spots. Previously to such services becoming available in the last twenty years it was all a matter of dousing and asking the areas eldest inhabitants of past disasters. One prime example being the fact that the church near the cliffs of 'Es Cubells' was built half upon a solid rock strata and half upon the loose clay and rock amalgam of the cliffs. The inevitable occurred and it cracked in half as it settled, now being propped up by massive and ugly buttresses. The fact that speculators were then recently allowed to build mansions upon these fragmented cliffs is another story to be explored later. Geological history may be a dry matter, but to ignore it is to find that the very wet matter of your having built your house at the end of a funnel valley where 'a once in a hundred year flood' explodes onto the plain! See Ibizaholidays.com for more history.
