The northern two-thirds of Chile lie on top of the telluric Nazca Plate, which, moving eastward about ten centimeters a year, is forcing its way under the continental plate of South America.
This movement has resulted in the formation of the Peru-Chile Trench, which lies beyond a narrow band of coastal waters off the northern two-thirds of the country. The trench is about 150 km (93 mi) wide and averages about 5,000 m (16,404 ft) in depth. At its deepest point, just north of the port of Antofagasta, it plunges to 8,066 m (26,463 ft). Although the ocean’s surface obscures this fact, most of Chile lies at the edge of a profound precipice.
The same telluric displacements that created the Peru-Chile Trench make the country highly prone to earthquakes. During the twentieth century, Chile has been struck by twenty-eight major earthquakes, all with a force greater than 6.9 on the Richter scale.
The strongest of these occurred in 2010 (registering an estimated 8.8 on the Richter scale) and in Valdivia 1960 (reaching 9.5). This latter earthquake occurred on May 22, the day after another major quake measuring 7.25 on the Richter scale, and covered an extensive section of south-central Chile. It caused a tsunami that decimated several fishing villages in the south and raised or lowered sections of the coast as much as two meters.
The clash between the Earth’s surface plates has also generated the Andes, a geologically young mountain range that, in Chilean territory alone, includes about 620 volcanoes, many of them active. Almost sixty of these had erupted in the twentieth century by the early 1990s. More than half of Chile’s land surface is volcanic in origin.
About 80 percent of the land in Chile is made up of mountains of some form or other. Most Chileans live near or on these mountains.
The majestically snowcapped Andes and their precordillera elevations provide an ever-present backdrop to much of the scenery, but there are other, albeit less formidable, mountains as well. Although they seemingly can appear anywhere, the non-Andean mountains usually form part of transverse and coastal ranges.
The former, located most characteristically in the near north and the far north natural regions, extend with various shapes from the Andes to the ocean, creating valleys with an east-west direction. The latter are evident mainly in the center of the country and create what is commonly called the Central Valley (Valle Central) between them and the Andes.
In the far south, the Central Valley runs into the ocean’s waters. At this location, the higher elevations of the coastal range facing the Andes become a multiplicity of islands, forming an intricate labyrinth of channels and fjords that have been an enduring challenge to maritime navigators.
Much of Chile’s coastline is rugged, with surf that seems to explode against the rocks lying at the feet of high bluffs. This collision of land and sea gives way every so often to lovely beaches of various lengths, some of them encased by the bluffs.
The Humboldt Current, which originates northwest of the Antarctic Peninsula (which juts into the Bellingshausen Sea) and runs the full length of the Chilean coast, makes the water frigid. Swimming at Chile’s popular beaches in the central part of the country, where the water gets no warmer than 15 °C (59 °F) in the summer, requires more than a bit of fortitude.
Chilean territory extends as far west as Polynesia. The best known of Chile’s Pacific Islands is Easter Island (Isla de Pascua, also known by its Polynesian name of Rapa Nui), with a population of 2,800 people.
Located 3,600 km (2,237 mi) west of Chile’s mainland port of Caldera, just below the Tropic of Capricorn, Easter Island provides Chile a gateway to the Pacific. It is noted for its 867 monoliths (Moais), which are huge (up to twenty meters high) and mysterious, expressionless faces sculpted of volcanic stone.
The Juan Fernández Islands, located 587 km (365 mi) west of Valparaíso, are the locale of a small fishing settlement. They are famous for their lobster and the fact that one of the islands, Robinson Crusoe Island, is where Alexander Selkirk, the inspiration for Daniel Defoe’s novel, was marooned for about four years.