Coatepeque Caldera
"The 7 x 10 km Coatepeque caldera, its eastern side filled by a caldera lake, was formed by collapse of a group of stratovolcanoes immediately east of Santa Ana volcano. The height of the caldera rim increases to 800 m on the west, where it partially truncates Santa Ana volcano. The caldera was formed during a series of major rhyolitic explosive eruptions between about 72,000 and 51,000 years ago. Post-caldera eruptions included the formation of basaltic cinder cones and lava flows near the western margin of the caldera and the extrusion of a half dozen rhyodacitic lava domes along a NE-SW line near the caldera lake margins. The highest of the domes forms the wooded island of Isla de Cabra, or Cerro Grande. The age of the domes is not known precisely, but the youngest dome, Cerro Pacho, was estimated to have formed less than 10,000 years ago. Hot springs occur near the lake margins, but no verified historical eruptions have occurred from Coatepeque."  -Smithsonian Volcano Archive
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