The Juan Fernández Ridge is a

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

island and

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

chain on the

Nazca plate The Nazca plate or Nasca plate, named after the Nazca region of southern Peru, is an oceanic list of tectonic plates, tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction, along the Peru– ...

. It runs for about in a west–east direction from the Juan Fernández hotspot to the Peru–Chile Trench between the latitudes of 32-34° S before subducting beneath the South American plate near

Valparaíso Valparaíso () is a major city, Communes of Chile, commune, Port, seaport, and naval base facility in the Valparaíso Region of Chile. Valparaíso was originally named after Valparaíso de Arriba, in Castilla–La Mancha, Castile-La Mancha, Spain ...

. The ridge forms a deep underwater corridor about below sea level, and was formed by upwelling of hot material from deep underground more than 22 million years ago. The ridge affects the geology of the region, and causes volcanic activity and earthquakes.

Location

Juan Fernández Ridge is a chain of

islands and

s on the

. It runs for about in a west–east direction from the Juan Fernández hotspot to the Peru–Chile Trench between the latitudes of 32-34° S before subducting beneath the South American plate near

Geology

The ridge was formed by upwelling of a deep plume of hot material from the mantle of the Earth. The ridge forms a deep underwater corridor about below sea level, and is made up of four island groups, with multiple summits. The ocean floor around the ridge is estimated to be 22 to 37 million years old. The Juan Fernández Ridge which normally runs east-west, bends northeast near the O'Higgins seamounts. This results in the ridge

subducting Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second pla ...

against the southern edge of the Valparaíso Basin, resulting in pushing the continental plate. The ridge acts like a wall trapping

sediments Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

behind it. On the upper side, the slope is worn away, while building up sediments further south, where the ridge hasn’t worn yet. These surface changes influence volcanic activity in the region and might be connected to earlier tectonic events that helped shape the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

mountains. Earthquake data from seismic studies have resulted in the discover of a double seismic zone inside the subducting Nazca Plate. The lower layer of earthquakes happens about below the upper layer, which starts about from the surface to meet the lower layer at a depth of . The stress is caused mainly by the collision of tectonic plates and the thickness of the continental crust. In the upper layers, it is squeezed horizontally, while in the lower layers, it is being stretched in the same direction as the plate movement due to the weight of the crust above it. The cold temperature and water released from minerals deep in the earth helps weaken the rock and allows earthquakes to happen, while the stress direction controls how those earthquakes rupture.

References

{{DEFAULTSORT:Juan Fernandez Ridge Juan Fernández Islands Underwater ridges of the Pacific Ocean Oceanography Hotspot tracks Volcanoes of Valparaíso Region