Cerro de la Calavera (also known as Mount Calavera) is an ancient

plug dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...

volcano that last erupted 22 million years ago during the

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

of the

Farallon Plate The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west c ...

. It is located within the city of

Carlsbad, California Carlsbad is a coastal city in the North County region of San Diego County, California, United States. The city is south of downtown Los Angeles and north of downtown San Diego. As of the 2020 census, the population of the city was 114,746. ...

in the United States. Cerro de la Calavera is only one of three volcanic plugs in Southern California and can easily be seen from either northbound Interstate 5 at Cannon Road or westbound on Lake Boulevard. Cerro de la Calavera is located within the Lake Calavera Preserve offering county maintained trails that lead directly into the ancient volcano, making for great hiking adventures. Lake Calavera and the dam that holds it lie in the shadow of the mountain.

References

Carlsbad, California Subduction volcanoes Miocene lava domes Volcanoes of California {{US-geology-stub