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San Juan

Photo of this volcano
  • Mexico
  • Trans-Mexican Volcanic Belt
  • Composite | Stratovolcano(es)
  • Pleistocene
  • Country
  • Volcanic Province
  • Landform | Volc Type
  • Last Known Eruption
  • 21.47°N
  • 104.97°W

  • 2,240 m
    7,349 ft

  • 341810
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports available for San Juan.

The Global Volcanism Program has no Weekly Reports available for San Juan.

The Global Volcanism Program has no Bulletin Reports available for San Juan.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

The Global Volcanism Program is not aware of any Holocene eruptions from San Juan. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the San Juan page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

Deformation History

There is no Deformation History data available for San Juan.

Emission History

There is no Emissions History data available for San Juan.

Photo Gallery

The locally widespread Tepic Pumice is exposed in this quarry on the NW outskirts of the city of Tepic. The zoned rhyodacitic-andesitic pumice, forming the upper half of this exposure, was erupted about 15,000 years ago and resulted in the formation of a 4-km-wide caldera at the summit of San Juan volcano. The 5.6 cu km Tepic Pumice deposit underlies the city of Tepic, the captial city of Narayit state, to thickness of 2-9 m.

Photo by Jim Luhr, 1976 (Smithsonian Institution).
Following the eruption of the Tepic Pumice and the formation of an elongated caldera at the summit of San Juan volcano, a lava dome was constructed within the caldera. The dome forms the rounded forested area in front of the western caldera rim, which marks the horizon. The caldera is 4 km wide in the E-W direction of this photo and 1 km wide in a N-S direction. Andesitic lava flows (left center) erupted from the dome and flowed across the caldera floor to its eastern side.

Photo by Jim Luhr, 1979 (Smithsonian Institution).
Volcán San Juan, the NW-most major volcano of the Mexican Volcanic Belt, displays an irregular profile west of the city of Tepic. The northern wall of a 1 x 4 km wide, oval-shaped caldera that was created about 15,000 years ago forms the right-hand horizon. The rounded notched peak on the center horizon is an intracaldera lava dome that was constructed shortly thereafter. The flanks of Cerro Alto stratovolcano, the 2240 m high point of the San Juan volcanic complex, can be seen at the extreme left.

Photo by Jim Luhr, 1976 (Smithsonian Institution).
A composite aerial photo with north to the top shows the lighter-gray summit of San Juan volcano just left of the center of the photo. Cerro Alto, the highest peak of the San Juan complex, forms the dark area at the lower left. A dark shadow highlights a 5-km-long NE-trending ridge that marks an eruptive fissure of the cone-building stage of San Juan. Prominent leveed lava flows that reach the northern flank mark the latest eruptive products of San Juan. The cities of Tepic and Jalisco lie at the upper and lower right, respectively.

Photo courtesy of Jim Luhr (Smithsonian Institution).
GVP Map Holdings

Maps are not currently available due to technical issues.

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included.

Smithsonian Sample Collections Database

There are no samples for San Juan in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites