The indistinct caldera at the right-center is the eroded Tambor Grande caldera, one of several areas of Quaternary volcanic rocks along the Atlantic coastal plain at the SE tip of Nicaragua. The Río San Juan forms the boundary between Costa Rica on the south and Nicaragua on the north. Tambor Grande has preserved its morphology despite its occurrence within an area of heavy rain forest precipitation.

Radar image, 1971 (courtesy of Jaime Incer).

This image is made available under the Creative Commons BY-NC 4.0 license terms.

Tambor Grande